ersatztv/docs/decisions.md

Decisions — lifecycle log

Purpose: why the codebase does what it does, so agents don't "fix" an established convention or relitigate a settled call. Update this doc (or a topic file under docs/decisions/) in the same PR that changes any fact below (or that establishes a new convention worth recording).

Lifecycle, not append-only (ersatztv#521, supersedes the ersatztv#303 H9 append-only mechanic). A migrated record is an H2 whose first non-blank content line is a metadata block:

YYYY-MM-DD — Title … (#issue) `key: area.topic` · `status: active` · `since: YYYY-MM-DD` · `supersedes: none` · `superseded-by: none` Rule: one-line current rule. Signals: concept · paths: a/b.yml · issues: #issue Mechanics: docs/some-doc.md → section <rationale prose …>

(Blockquoted here so the illustrative key/heading don't parse as a real record; the ## 2026-07-17 — No persistent compiler servers … entry below is a live example.) Five metadata fields: key (dotted, e.g. ci.runner-placement), status, since, supersedes, superseded-by. The Signals: line is also required (validator-enforced, ersatztv#545): it is the keywords/paths MemPalace's recall matches on, so a record without it ingests with weak recall metadata and under-surfaces — pack it with synonyms, symbol names, paths:, and issue refs. status is one of:

• active — the current, authoritative record for its key. Exactly one active record per key.
• superseded — reversed by a newer record; relocated to docs/decisions/archive/ with superseded-by: <new key> pointing forward, and the successor's supersedes pointing back.
• retired — no longer applicable (not reversed, just obsolete); also lives in the archive.

(An H2 with no metadata block is legacy-unmigrated — not yet ported to this schema. The validator tolerates these and reports a count; they trend to zero over time, not required to hit zero at once.)

Supersession is same-PR, not a later consolidation pass: add the new active record, then relocate the predecessor's file (or section) into docs/decisions/archive/ with the metadata above rewritten to status: superseded (or retired) and the reciprocal supersedes/superseded-by links filled in on both records. Never silently rewrite a record's rationale prose in place.

Generated active catalog: docs/decisions/README.md is generated from every active record (this file + the topic files, excluding the archive) via scripts/build_decisions_catalog.py — run it after any status change; CI's decisions lifecycle job fails on drift (--check).

Enforcement: scripts/decisions_validate.py checks metadata well-formedness (including a required Signals: line), one-active-record-per-key, reciprocal links, that no record vanishes from the active set without an archive copy, that the active catalog is in sync, and an aggregate active-corpus line budget (replaces the old 1800-line floor on this single file). The Husky pre-commit hook runs the structural checks over the working tree; the CI decisions lifecycle job additionally runs the body-diff check with --base/--head.

[decisions-edit] is now narrow: it is required ONLY when a commit changes the rationale prose of a surviving or archived record — a factual correction to already-written history. Routine lifecycle writes (adding a new active record, relocating a superseded/retired record to the archive, updating metadata fields, regenerating the catalog) are token-free; the validator proves they're legitimate structurally instead of gating on the token.

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Index

Decisions are split between the chronological log in this file and four topic files under docs/decisions/ — large same-topic clusters extracted at the v26.9.0 consolidation (full rationale preserved). Check the relevant topic file below for its subject; otherwise scan the in-file entries.

Topic files:

• decisions/optimistic-concurrency.md — ETag / If-Match / Version optimistic concurrency (#253, #259, #265, #269). Mechanics: api-conventions.md §7a–§7c.
• decisions/api-auth-security.md — API/SPA auth & security posture (#197 bundles + #279 headers, #206, #283, #292, #295, #301, #319, #330).
• decisions/release-ci-governance.md — release / CI / merge governance (#303 H3/H4/H5/H6/H9/H10, #311, #314, #315, #335).
• decisions/spa-modularization.md — App.tsx screen/shell extraction epic #243 (#244, #245, #247).
• decisions/workflow-process.md — session workflow, CI-run triage, review routing, worktree/parallel-session hygiene and tooling gotchas (#542). Extracted from the kickoff handoff doc, which was their only copy.

In this file:

• 2026-06 — REST API wraps existing MediatR handlers 1:1, no service layer
• 2026-06 — UI rebuild is a React SPA (ChicoryTV) on the REST API, not a Blazor reskin
• 2026-07 — Response DTOs live in ErsatzTV.Core/Api, file-scoped #nullable enable
• 2026-07 — PUT-replace list endpoints derive Index from array order; alternate-schedules last row = catch-all default
• 2026-07 — Templates editor in the SPA is a table, not Blazor's drag-calendar
• 2026-07-07 — API artwork contract: rooted URLs produced server-side
• 2026-07-07 — Decode-style endpoints take a row id and look up server-side
• 2026-07-07 — Season/episode/music-video drill-in via parentId, not new child-listing endpoints
• 2026-07-07 — Convention docs read at session start, updated in-PR
• 2026-07-09 — Playback-troubleshooting completion feedback: poll status, no push channel
• 2026-07-09 — datetime-local instead of Chronic natural-language start parsing
• 2026-07-09 — SPA gates Download Media Sample while a session is active
• 2026-07-09 — OpenAPI spec mirrors the runtime Newtonsoft serializer (#198)
• 2026-07-09 — YAML playout validator: paste-textarea instead of a server file path
• 2026-07-09 — Channel numbers: prompt-driven sequential renumber instead of drag-to-reorder
• 2026-07-09 — "Table, not calendar" convention also covers the deco-templates editor
• 2026-07-11 — Trash "See all" reuses library-browse paging; search stays capped per kind (#213)
• 2026-07-11 — Logs page-size is a client-local preference, not a server ConfigElement
• 2026-07-11 — Logs column sorting: allow-listed sortField/sortDirection on GET /api/logs
• 2026-07-09 — Per-playout "Schedule reset" button dropped; Reset uses the server-default build mode
• 2026-07-09 — Collection custom order: move up/down buttons, any-kind collections
• 2026-07-10 — Shared "Add to…" layer lives in web/src/media/addTo/; select-mode is an explicit toggle
• 2026-07-10 — Schedule-item GET returns a flat, non-polymorphic DTO (ScheduleItemResponseModel)
• 2026-07-10 — Playout API mutations return 409 while the build lock is held (#215)
• 2026-07-11 — Schedules SPA editor: draft/explicit-Save over instant-persist; Copy includes multi/smart/rerun; shuffled-GET normalization preserved
• 2026-07-11 — Channel editor: bare-create entry point + external-logo mutual exclusion (#212)
• 2026-07-11 — EntityLocker: atomic flags + single-owner release discipline, no owner tokens (#231)
• 2026-07-11 — Media-source management REST write API + SPA (#202)
• 2026-07-11 — Legacy→SPA redirect matcher: exact map + ordered segment-template patterns (#204)
• 2026-07-11 — Pre-removal Blazor rollback tag blazor-final (#205)
• 2026-07-11 — Async-op API contract normalization + playout build observability + F9 scan endpoints (#235)
• 2026-07-11 — Post-commit side effects run on CancellationToken.None (generalized from #251 to #254)
• 2026-07-12 — External-collections scans get an authoritative status surface (#271); the SPA timeout is retired
• 2026-07-11 — Blazor Server UI removed (#91 phase b)
• 2026-07-12 — Live-E2E is a required step for API write-path handler changes (#303)
• 2026-07-12 — TopBar primary-action button: wire creates, drop the rest (#238)
• 2026-07-13 — API versioning: the whole /api surface is mounted at /api/v1, additive-only after freeze (#286)
• 2026-07-13 — Scheduling API hardening: null-name 500s, duplicate template items, unreachable 404 (#172)
• 2026-07-16 — Functional-E2E CI harness: advisory curl-contract job over an app booted from source (#299)
• 2026-07-16 — Optional advertised IPTV base URL (iptv.base_url) resolved centrally in the two generators (#340)
• 2026-07-16 — Auto-tuning enumerates via EF, persists via SmartCollection; additive coexistence (#69)
• 2026-07-16 — Per-playout reshuffle = scoped Reset build; seed surfaced (#71)
• 2026-07-17 — Clock-boundary schedule padding already exists (FillerMode.Pad); #77 verified, convenience toggle deferred
• 2026-07-17 — Shuffle-source construction extracted to ShuffleSourceBuilder; per-family seam, not a god-factory (#380)
• 2026-07-17 — Seasonal / date-conditional scheduling already exists (alternate schedules / playout templates); #73 closed as implemented
• 2026-07-17 — Auto-Tune DetailPanel member list = live search-index roll-up, not EF enumeration (#384)
• 2026-07-17 — No persistent compiler servers in CI; every services: container gets an explicit cap; #390's small-lane move reversed (#406)
• 2026-07-17 — Channel health on the API = the raw PlayoutCount fact on the list DTO, not a derived status enum (#72)
• 2026-07-17 — Weighted / fair-share distribution is a new WeightedShuffle order; ShuffleInOrder is anti-clumping, not fair-share (#70)
• 2026-07-17 — Auto-Tune per-channel overrides reuse the Channel Builder advanced-options DTO; weights + bug-colour logo split out to #425 (#385)
• 2026-07-17 — Health-check remediation is server-declared {Kind, Target} on an additive DTO; the SPA acts on it (#164)
• 2026-07-18 — Auto-Tune DetailPanel SPA: reusable SlideOver + shared advanced-options model; decorative panes dropped to match the backend (#386)
• 2026-07-18 — SmartCollection rule builder: compile-only closed subset, no stored AST, one-level nesting (#176)
• 2026-07-18 — Auto-Tune per-source weights ride #70's MultiCollection machinery; created at tune time, not a post-hoc PUT (#425)
• 2026-07-18 — Search all-items is paged to cap DoS exposure; SPA add-all pages to completeness (#293)
• 2026-07-18 — Unsupported PlaybackOrder is loud at build time; a declared support matrix and tripwire test make new orders safe by construction (#403)
• 2026-07-18 — CI build-once was measured and rejected; keep the #420 tree-skip
• 2026-07-18 — Never-scanned LastScan surfaces as null at the API boundary, not the 0001-01-01 MinValue sentinel (#409)
• 2026-07-19 — WeightedShuffle SPA: weights edited on the multi-collection, order offered only on classic MultiCollection schedule items; fair-share is a reset not a mode (#404)
• 2026-07-19 — Health-check results are TTL-cached; ?refresh=true forces a fresh run (#431)
• 2026-07-19 — CI test job reports a sampled true peak-anon, not cache-inflated memory.peak (#412)
• 2026-07-20 — External-URL channel logos pass through to the graphics engine; never File.Exists-gated, never ffmpeg-native (#502)
• 2026-07-20 — Remote graphics-engine images are fetched through a bounded, pooled IRemoteImageFetcher; re-fetched per element init, not cached (#511)
• 2026-07-21 — Decision records carry a lifecycle schema, validated by a script; append-only-by-diff is retired (#521)
• 2026-07-21 — Parallel orientation + selection is the startup protocol; #237 retired (#520)
• 2026-07-21 — External channel-logo URLs are downloaded and cached at save time; the render path never fetches a logo (#525)
• 2026-07-21 — Check the worked issue before the decision corpus; a closed tracker's comments need no retrofit (#524)
• 2026-07-21 — Work-ahead slots are claimed atomically by the caller, released by the transcode it hands them to (#536)
• 2026-07-21 — Session end fast-forwards the shared checkout; a stale tree serves stale FILES (#541)

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2026-06 — REST API wraps existing MediatR handlers 1:1, no service layer

key: api.mediatr-passthrough · status: active · since: 2026-06 · supersedes: none · superseded-by: none Rule: The REST API is thin controllers over existing MediatR handlers, with no new service/business-logic layer. Signals: CQRS passthrough, Either<BaseError, T> mapping, handler-level fixes not controller papering · paths: docs/rest-api.md, docs/api-conventions.md §3 · issues: #2, #172 Mechanics: docs/api-conventions.md §3

The REST API (#2, docs/rest-api.md) is thin controllers over the existing MediatR Create/Update/Delete handlers — no new service/business-logic layer was introduced, since nearly every handler already returns Either<BaseError, T>, which maps cleanly to HTTP status codes. Latent handler bugs (missing existence checks, KeyNotFoundException risk, etc.) are fixed at the handler, converting what would have 500'd into a proper 404/422 — not papered over in the controller. Established across the #2a–#2e gap-issue PRs. Deep FK ids nested inside item-list request bodies (e.g. a schedule item's CollectionId) are deliberately not existence-checked at that depth, to avoid N+1 validation queries — precedent set by the schedules endpoints (#172); see docs/api-conventions.md §3 for the up-to-date statement of this rule.

2026-06 — UI rebuild is a React SPA (ChicoryTV) on the REST API, not a Blazor reskin

key: spa.spa-rebuild-decision · status: active · since: 2026-06 · supersedes: none · superseded-by: none Rule: The UI is a full React SPA (ChicoryTV) rebuild over the REST API, not a Blazor Server reskin. Signals: Blazor removal phases (a)/(b), root-flip, legacy-route redirects · paths: ErsatzTV/LegacyUiRedirects.cs, docs/blazor-route-parity.md · issues: #59, #91, #148 Mechanics: docs/blazor-route-parity.md

#59 committed to a full SPA rebuild rather than reskinning Blazor Server pages. Blazor removal is split into two phases under #91: (a) root-flip (SPA becomes /) + legacy-route redirects — DONE, merged via PR #148 (ErsatzTV/LegacyUiRedirects.cs, feat/91-cutover → main). (b) full Blazor removal — gated on every route having an SPA equivalent; tracked route-by-route in docs/blazor-route-parity.md.

2026-07 — Response DTOs live in ErsatzTV.Core/Api, file-scoped #nullable enable

key: api.response-dtos · status: active · since: 2026-07 · supersedes: none · superseded-by: none Rule: New REST response DTOs live in ErsatzTV.Core/Api/<Domain>/*ResponseModel.cs with a file-scoped #nullable enable pragma; controllers never expose Application VM types directly. Signals: nullable-disabled Core project, ResponseModel mirroring ViewModel shape · paths: ErsatzTV.Core/Api, docs/api-conventions.md §2 · issues: none cited Mechanics: docs/api-conventions.md §2

New REST response DTOs go in ErsatzTV.Core/Api/<Domain>/*ResponseModel.cs and mirror the shape of the corresponding Application-layer ViewModel — controllers never expose VM types directly. Because ErsatzTV.Core.csproj sets <Nullable>disable</Nullable> project-wide, any response-model file with an optional member needs its own #nullable enable pragma at the top (most already have one). ErsatzTV.Application has no nullable context at all — do not add ? annotations to types living there; that's a Core/Api-layer-only convention. Full detail: docs/api-conventions.md §2.

2026-07 — PUT-replace list endpoints derive Index from array order; alternate-schedules last row = catch-all default

key: api.put-replace-index-order · status: active · since: 2026-07 · supersedes: none · superseded-by: none Rule: PUT-replace-the-whole-list endpoints derive each item's Index from its request-array position, never a client-supplied field; alternate-schedule/playout-template rows are evaluated in Index order with the least-conditional row placed last as the catch-all default. Signals: ReplaceScheduleItemsRequest.ToCommand, IAlternateScheduleItem, first-match-wins · paths: AlternateScheduleSelector.cs · issues: #179 Mechanics: PR #179, AlternateScheduleSelector.cs

For "replace the whole list" endpoints (PUT over a collection — schedule items, template items, etc.), the item's Index is derived from its position in the request array, not from a client-supplied index/order field — established by ReplaceScheduleItemsRequest.ToCommand (Items.Select((item, index) => item.ToReplaceCommand(index))). Separately, ProgramScheduleAlternate and PlayoutTemplate rows (both IAlternateScheduleItem) are evaluated in Index order, first-match-wins; the convention is to place the least-conditional (or unconditional) row last so it acts as the catch-all default. Established by the alternate-schedules work (PR #179, AlternateScheduleSelector.cs).

2026-07 — Templates editor in the SPA is a table, not Blazor's drag-calendar

key: spa.templates-editor-table · status: active · since: 2026-07 · supersedes: none · superseded-by: none Rule: The SPA templates editor renders day/block assignment as a table, not Blazor's drag-and-drop calendar grid — an accepted, deliberate parity deviation. Signals: TemplateEditor.razor vs table UI · paths: /app/templates/{id} · issues: #173 Mechanics: PR #173

The legacy Blazor TemplateEditor.razor used a drag-and-drop day-grid calendar UI. The SPA equivalent (/app/templates/{id}, PR #173) renders the same day/block assignment as a table instead. This is an accepted, deliberate parity deviation — don't "fix" it to match Blazor's interaction model without discussing it first.

2026-07-07 — API artwork contract: rooted URLs produced server-side

key: api.artwork-rooted-urls · status: active · since: 2026-07-07 · supersedes: none · superseded-by: none Rule: API response DTOs return artwork as rooted, directly-usable URLs (plus passthrough for absolute/proxy URLs), never relative Blazor-convention paths. Signals: no SPA <base href>, ApiArtwork helper · paths: ErsatzTV.Core/Api/ApiArtwork.cs, ErsatzTV.Application/LibraryBrowse/Queries/GetLibraryBrowseItemsHandler.cs · issues: none cited (PR #181, PR #183) Mechanics: ErsatzTV.Core/Api/ApiArtwork.cs

API response DTOs return artwork as rooted, directly-usable URLs (/artwork/posters/..., /artwork/thumbnails/..., /artwork/fanart/...), plus passthrough for absolute http(s):// URLs and Jellyfin/Emby proxy variants. Established by PR #181 (ErsatzTV.Application/LibraryBrowse/Queries/GetLibraryBrowseItemsHandler.cs, private Artwork(...) helper — comment: "Returns a rooted, directly-usable artwork URL for the SPA's <img src>... the SPA [needs it pre-rooted]"), then generalized into the reusable ApiArtwork helper (ErsatzTV.Core/Api/ApiArtwork.cs, PR #183). Root cause: the SPA has no <base href>, unlike Blazor, so relative artwork paths that worked for Blazor pages 404 in the SPA. Do not reuse the Application-layer Mappers used by Blazor (e.g. MediaCards/Television mappers) for new API DTOs — those still return old Blazor-convention relative paths; map from the domain/VM directly and root the path via ApiArtwork.

2026-07-07 — Decode-style endpoints take a row id and look up server-side

key: api.decode-by-id · status: active · since: 2026-07-07 · supersedes: none · superseded-by: none Rule: Endpoints that decode/expand opaque stored state accept a database row id and resolve it server-side rather than round-tripping client-supplied serialized state. Signals: PlayoutHistoryDetailsResponseModel · paths: PlayoutController.GetHistoryDetails · issues: none cited (PR #182) Mechanics: GET /api/playouts/history/{id}, PlayoutController.GetHistoryDetails

Endpoints that decode/expand opaque stored state accept a database row id and resolve server-side, rather than accepting client-supplied serialized state to decode. Established by GET /api/playouts/history/{id} (PlayoutController.GetHistoryDetails, PR #182) — the row's raw JSON (Key/Details) is decoded server-side into PlayoutHistoryDetailsResponseModel, the client never round-trips the raw payload itself.

2026-07-07 — Season/episode/music-video drill-in via parentId, not new child-listing endpoints

key: api.parentid-drillin · status: active · since: 2026-07-07 · supersedes: none · superseded-by: none Rule: Media drill-in (season/episode/artist/music-video) is served by an optional parentId query param on library-browse, not dedicated per-kind child-listing endpoints. Signals: library-picker season drill-in, media-detail browsing · paths: library-browse endpoint · issues: none cited (PRs #181/#183) Mechanics: library-browse endpoint parentId param

Rather than adding dedicated child-listing endpoints per media kind (e.g. "list episodes of a season"), the library-browse endpoint takes an optional parentId query param and the SPA drills in by re-querying with it. Established across PRs #181/#183 (library-picker season drill-in, then media-detail's season/episode/artist/music-video browsing). Avoids a combinatorial explosion of per-kind child endpoints.

2026-07-07 — Convention docs read at session start, updated in-PR

key: docs.convention-docs-session-start · status: active · since: 2026-07-07 · supersedes: none · superseded-by: none Rule: Docs-first, not source-first: conventions (api-conventions, spa-conventions, e2e-local, blazor-route-parity, domain-model, decisions, README) are read from docs, not reverse-engineered from code, via docs/README.md's task-signal map — only the sections it points to for the task at hand, not the whole set. Each doc is updated in the same PR that changes what it documents, replacing deferred/follow-up doc updates. Signals: docs/README.md index, ApiControllerSecurityTests drift · paths: docs/README.md, docs/api-conventions.md §6 · issues: #184, #185. Session-start reading order is now the task-signal map — see startup.parallel-orientation. Mechanics: docs/README.md

docs/api-conventions.md, docs/spa-conventions.md, docs/e2e-local.md, docs/blazor-route-parity.md, docs/domain-model.md, docs/decisions.md, and docs/README.md are the standing reference set every ChicoryTV session should read before starting work, and each one carries an explicit "update this doc in the same PR" rule rather than deferring doc updates to a follow-up. These docs replace per-session recon — an agent reads the index (docs/README.md) and the relevant convention doc instead of re-deriving conventions from the code each time it starts API/SPA/E2E/parity work. A testing map and a generated-endpoint index are tracked as still-to-come under #185. Drafting this doc set also surfaced a drift in ApiControllerSecurityTests.cs's hardcoded controller registry (several controllers under ErsatzTV/Controllers/Api/ are missing from it — see docs/api-conventions.md §6) — tracked as a follow-up under #184 rather than fixed inline, since it's a pre-existing gap, not something this doc-drafting pass caused.

2026-07-09 — Playback-troubleshooting completion feedback: poll status, no push channel

key: spa.playback-troubleshoot-poll · status: active · since: 2026-07-09 · supersedes: none · superseded-by: none Rule: The playback-troubleshooting screen reports FFmpeg completion by polling GET /api/troubleshoot/playback/status (~2s) rather than a server push channel. Signals: PlaybackTroubleshootingScreen.tsx, ICourier/ISnackbar parity · paths: web/src/screens/PlaybackTroubleshootingScreen.tsx · issues: #145 Mechanics: GET /api/troubleshoot/playback/status

The SPA playback-troubleshooting screen (PlaybackTroubleshootingScreen.tsx, #145) reports FFmpeg completion by polling GET /api/troubleshoot/playback/status every ~2s while a session is running (plus one poll on mount so a session started elsewhere still gates Play), rather than a server push. The status endpoint returns { state, exitCode, speed, logs }; the screen captures the running→completed/failed transition in local component state and surfaces a completion notice (success on exit 0, warning otherwise) — the SPA equivalent of the Blazor page's MediatR ICourier/ISnackbar PlaybackTroubleshootingCompletedNotification. Chosen over SignalR/SSE because the SPA has no push channel and troubleshooting sessions are short and user-initiated, so a lightweight poll (started on Play, stopped on settle/unmount) is simpler than standing up a new real-time transport. Speed thresholds and the "(Speed: Nx)" badge colors are copied verbatim from the Blazor GetSpeedClass (red <0.9, green >1.1, amber otherwise).

2026-07-09 — datetime-local instead of Chronic natural-language start parsing

key: spa.datetime-local-input · status: active · since: 2026-07-09 · supersedes: none · superseded-by: none Rule: The channel-mode date/time input uses a native <input type="datetime-local"> instead of free-text Chronic natural-language parsing. Signals: playback.m3u8 start param, ISO-8601 round-trip · paths: none beyond the screen itself · issues: none cited Mechanics: playback-troubleshooting screen, playback.m3u8 start param

The channel-mode "Date and Time" input in the SPA playback-troubleshooting screen uses a native <input type="datetime-local">, a deliberate deviation from the Blazor page, which parsed a free-text field with Chronic.Core.Parser (natural language like "yesterday at 8pm"). The SPA has no Chronic dependency and a picker is unambiguous; the selected local datetime is sent to playback.m3u8 as an ISO-8601 start param via new Date(value).toISOString(), which the controller binds to DateTimeOffset? exactly as the Blazor round-trip ("o") format did.

2026-07-09 — SPA gates Download Media Sample while a session is active

key: spa.download-sample-gate · status: active · since: 2026-07-09 · supersedes: none · superseded-by: none Rule: The SPA disables both Download Media Sample and Download Results while a troubleshooting session is starting/running (Blazor only gated Download Results). Signals: I/O contention with the live transcode · paths: none · issues: none cited Mechanics: playback-troubleshooting screen

Minor intentional deviation: the SPA playback-troubleshooting screen disables Download Media Sample (alongside Download Results) while a troubleshooting session is starting/running; Blazor only gated Download Results. Both downloads compete with the live transcode for I/O and the sample archiver reads the same media file, so gating both during a session is strictly safer and costs nothing (sessions are short).

2026-07-09 — OpenAPI spec mirrors the runtime Newtonsoft serializer (#198)

key: api.openapi-mirrors-runtime · status: active · since: 2026-07-09 · supersedes: none · superseded-by: none Rule: The generated OpenAPI spec is made to match the runtime Newtonsoft wire contract (via NewtonsoftSchemaNamingTransformer), not the reverse. Signals: CustomContractResolver, CustomNamingStrategy, System.Text.Json drift · paths: OpenApiSerializerContractTests · issues: #198 Mechanics: NewtonsoftSchemaNamingTransformer, OpenApiSerializerContractTests

The generated OpenAPI document is made to follow the runtime JSON contract, not the reverse. Runtime /api/* responses are serialized by Newtonsoft via CustomContractResolver/CustomNamingStrategy (camelCase + a FFmpegProfileId→ffmpegProfileId special case + [JsonProperty] overrides such as ChannelResponseModel.FFmpegProfile→ffmpegProfile), while Microsoft.AspNetCore.OpenApi generates the spec from System.Text.Json metadata, whose camelCase drifted (fFmpegProfileId, fFmpegProfile). That drift fed the SPA the wrong key. Rather than hand-patch the spec or change the wire format (breaking clients), we added NewtonsoftSchemaNamingTransformer — an OpenAPI schema transformer registered on all three documents that renames each schema property through the same Newtonsoft contract resolver the runtime uses, so the spec matches the wire format by construction. A contract test (OpenApiSerializerContractTests) serializes representative DTOs through the real runtime settings and pins the spec property sets to them. Decision: the wire format is the source of truth; the spec follows it via the real contract resolver. This also fixed a latent SPA bug (the channel-list "FFmpeg profile" column read fFmpegProfile and always showed "Unassigned"). Issue #198.

2026-07-09 — YAML playout validator: paste-textarea instead of a server file path

key: spa.yaml-validator-textarea · status: active · since: 2026-07-09 · supersedes: none · superseded-by: none Rule: The YAML playout validator takes pasted YAML via a <textarea>, not a server-side file path, since the SPA has no filesystem access. Signals: YamlValidatorScreen.tsx · paths: web/src/screens/YamlValidatorScreen.tsx · issues: none cited Mechanics: YamlValidatorScreen.tsx

The legacy Blazor YAML playout validator took a server-side file path (read directly off the container's filesystem). The SPA's YamlValidatorScreen.tsx instead uses a paste <textarea> — a deliberate deviation, not an oversight. The SPA runs entirely client-side against /api/* and has no access to the server's filesystem, so a file-path field would either need a new filesystem-browsing endpoint or silently fail; pasting the YAML directly is simpler and matches how every other SPA editor already round-trips content through the API instead of the disk.

2026-07-09 — Channel numbers: prompt-driven sequential renumber instead of drag-to-reorder

key: spa.channel-renumber-prompt · status: active · since: 2026-07-09 · supersedes: none · superseded-by: none Rule: Channel renumbering uses a sequential prompt()-driven "Renumber" action instead of drag-to-reorder. Signals: App.tsx Renumber action · paths: web/src/App.tsx · issues: none cited Mechanics: App.tsx Renumber action

The legacy Blazor channel list let you drag-and-drop rows to reorder channel numbers. The SPA (App.tsx) instead offers a "Renumber" action that walks the list and asks for each channel's new number via a sequence of native prompt() calls. Deliberate deviation: drag-to-reorder needs a dedicated drag library and a bespoke reorder-persistence endpoint; a sequential prompt reuses the existing per-channel update call and needs no new UI dependency. Revisit only if channel counts grow large enough that prompt-per-channel becomes tedious.

2026-07-09 — "Table, not calendar" convention also covers the deco-templates editor

key: spa.deco-templates-table · status: active · since: 2026-07-09 · supersedes: none · superseded-by: none Rule: The deco-templates editor also renders its day/deco assignment as a table, extending (not replacing) the templates-editor-table convention. Signals: DecoTemplatesScreen.tsx, same accepted-deviation status · paths: web/src/screens/DecoTemplatesScreen.tsx · issues: none cited Mechanics: DecoTemplatesScreen.tsx

Extends the 2026-07 "Templates editor in the SPA is a table, not Blazor's drag-calendar" entry above (not editing that entry — this generalizes it): the deco-templates editor (DecoTemplatesScreen.tsx) follows the same convention, rendering its day/deco assignment as a table rather than reproducing Blazor's drag-and-drop calendar grid. Same rationale, same accepted-deviation status — don't "fix" either editor to match Blazor's interaction model without discussing it first.

2026-07-11 — Trash "See all" reuses library-browse paging; search stays capped per kind (#213)

key: api.search-paging-cap · status: active · since: 2026-07-11 · supersedes: none · superseded-by: none Rule: Search stays capped at 100 items per media kind; an overflowing kind's "See all" reuses library-browse paging instead of adding new API surface. Signals: GetLibraryBrowseItems, state:FileNotFound query · paths: GET /api/v1/search, GET /api/v1/library/browse · issues: #213 Mechanics: GET /api/v1/library/browse

GET /api/v1/search still returns at most 100 items per media kind, which is the cheap first page for the common case. For an overflowing kind, the SPA's "See all N …" action pages GET /api/v1/library/browse with query=state:FileNotFound, mediaType, pageNum, and pageSize=100, then appends the results client-side. This reuses the same GetLibraryBrowseItems query behind search, adds no API surface, and only pays for follow-up requests when a kind exceeds the first-page cap.

2026-07-11 — Logs page-size is a client-local preference, not a server ConfigElement

key: spa.logs-page-size-local · status: active · since: 2026-07-11 · supersedes: none · superseded-by: none Rule: The Logs page rows-per-page preference is stored in window.localStorage (ctv-logs-page-size), not a server ConfigElement. Signals: LogsScreen.tsx, wrapped-Storage pattern, designSystem.ts/auth.ts precedent · paths: LogsScreen.tsx, designSystem.ts · issues: none cited Mechanics: LogsScreen.tsx localStorage key ctv-logs-page-size

The legacy Blazor Logs page persisted the user's chosen rows-per-page via ConfigElementKey.LogsPageSize (SaveConfigElementByKey/GetConfigElementByKey), a per-server-instance setting stored in the DB. LogsScreen.tsx instead persists it to window.localStorage under ctv-logs-page-size (same wrapped-Storage pattern as designSystem.ts's theme preference: try/catch getter, validated against the known option set, falls back to a default) and restores it on mount. Deliberate deviation: this is a per-browser UI preference, not server/business state — no other client should see or be affected by it, so there is no reason to round-trip it through the API and grow a new /api/* surface (or reuse the generic config-element endpoints) just to store a page-size number. Follows the existing SPA localStorage convention (designSystem.ts theme, auth.ts token) rather than introducing a new persistence mechanism.

2026-07-11 — Logs column sorting: allow-listed sortField/sortDirection on GET /api/logs

key: api.logs-sort-params · status: active · since: 2026-07-11 · supersedes: none · superseded-by: none Rule: GET /api/logs takes allow-listed sortField (timestamp|level) and sortDirection (asc|desc) query params, normalized (not rejected) on an unrecognized value. Signals: MudTableSortLabel parity, clamp-not-422 normalization · paths: LogsController.GetLogs, LogsScreen.tsx · issues: none cited Mechanics: LogsController.GetLogs

Parity for Logs.razor's MudTableSortLabel columns (Timestamp, Level — Message was never sortable in Blazor either). LogsController.GetLogs adds sortField (timestamp | level, default timestamp) and sortDirection (asc | desc, default desc) query params, normalized server-side the same way pageNum/pageSize are clamped rather than rejected with a 422: an unrecognized sortField silently falls back to timestamp, an unrecognized sortDirection falls back to desc — the pre-existing default behavior (newest-first) is unreachable to break via a bad query string. LogsScreen.tsx renders the two sortable headers as buttons with a chevron indicating the active field/direction; clicking the active column toggles direction, clicking the other column switches to it ascending.

2026-07-09 — Per-playout "Schedule reset" button dropped; Reset uses the server-default build mode

key: spa.playout-reset-button · status: active · since: 2026-07-09 · supersedes: none · superseded-by: none Rule: The SPA keeps a single Reset action (server picks the default build mode) and drops Blazor's separate "Schedule reset" button since its capability already exists via the playout's Edit-details flow. Signals: POST /api/channels/{channelNumber}/playout/reset, no mode param · paths: none · issues: #210 Mechanics: POST /api/channels/{channelNumber}/playout/reset

Blazor's playouts page had both a per-playout Reset and a separate Schedule Reset control (setting the daily rebuild time). The SPA keeps Reset — POST /api/channels/{channelNumber}/playout/reset with no mode param, so the server picks the same default Blazor used (Classic → Refresh, everything else → Reset) — but drops the dedicated "Schedule reset" button: the daily rebuild time is already editable through the playout's Edit-details flow, so a second entry point would duplicate an existing capability. Deliberate deviation, not a lost capability. Issue #210.

2026-07-09 — Collection custom order: move up/down buttons, any-kind collections

key: spa.collection-custom-order-ui · status: active · since: 2026-07-09 · supersedes: none · superseded-by: none Rule: Collection custom ordering uses per-row Move up/Move down buttons (not drag) and is offered for any manual collection with custom order enabled, not just movies-only. Signals: CollectionsScreen.tsx, PUT /api/collections/{id}/custom-order, CustomOrderCollectionEnumerator · paths: CollectionsScreen.tsx · issues: #211 Mechanics: PUT /api/collections/{id}/custom-order

Blazor reordered collection items with SortableJS drag-and-drop and only enabled custom ordering for movies-only collections. The SPA (CollectionsScreen.tsx) uses per-row Move up / Move down buttons in an explicit reorder mode instead of drag (no new drag dependency; the mode loads ALL items first because PUT /api/collections/{id}/custom-order replaces the whole order from array position — submitting a partial page would scramble the rest), and does not replicate the movies-only gate: the API and the playback-side CustomOrderCollectionEnumerator sort by CustomIndex regardless of item kind, so the SPA offers reorder for any manual collection with custom order enabled. Issue #211.

2026-07-10 — Shared "Add to…" layer lives in web/src/media/addTo/; select-mode is an explicit toggle

key: spa.add-to-layer · status: active · since: 2026-07-10 · supersedes: none · superseded-by: none Rule: All add-to-collection/playlist/schedule affordances share one component layer at web/src/media/addTo/; multi-select is an explicit screen-level toggle, and the per-card menu offers schedule only for the server-validated kinds. Signals: AddToCollectionDialog, AddToPlaylistDialog, AddToScheduleDialog, AddToMenu, ProgramScheduleItemCommandBase.CollectionTypeMustBeValid · paths: web/src/media/addTo/ · issues: #208, #209 Mechanics: web/src/media/addTo/

The media mutation surface (#208/#209) is built on one reusable component group, web/src/media/addTo/ (media-domain components, like MediaPosterCard — not generic components/): AddToCollectionDialog (existing-collection Select + inline "(New collection)" create, Blazor AddToCollectionDialog.razor parity), AddToPlaylistDialog (group → playlist Selects, no inline create), AddToScheduleDialog (schedule Select; payload replicates Blazor's AddProgramScheduleItem.ForMediaItem defaults — see addTo/scheduleItem.ts), SaveAsSmartCollectionDialog, and AddToMenu (the drop-in popover for cards/detail pages via MediaPosterCard's actions slot). New screens wanting add-to affordances use this layer — don't build screen-local pickers. Two deliberate deviations from Blazor, applied consistently on the search and browse screens: (1) multi-select is an explicit screen-level "Select" toggle (off = cards open, on = cards select) rather than Blazor's always-on corner-select, because MediaPosterCard's select handler takes over the card's single click gesture; (2) the per-card menu offers collection/playlist for a single item of any kind, plus schedule only for shows/seasons/artists — collection/playlist is a superset of Blazor's per-card collection-only menu, while the schedule target is gated to exactly the kinds Blazor's AddProgramScheduleItem.ForMediaItem call sites offer, because the server validator (ProgramScheduleItemCommandBase.CollectionTypeMustBeValid) accepts only the TelevisionShow/TelevisionSeason/Artist per-media-item CollectionTypes and 422s the rest. "Add All" (query-wide) mirrors Blazor's two-step: materialize ids via GET /api/search/all-items, then reuse the id-list add endpoints — no query-based add command exists server-side. Issues #208/#209.

2026-07-10 — Schedule-item GET returns a flat, non-polymorphic DTO (ScheduleItemResponseModel)

key: api.schedule-item-flat-dto · status: active · since: 2026-07-10 · supersedes: none · superseded-by: none Rule: Schedule-item GET/POST/PUT use a flat, non-polymorphic ScheduleItemResponseModel (every subtype field promoted to a nullable top-level member) instead of the polymorphic Application VM hierarchy, with mutation field names matching ScheduleItemRequest 1:1 for a lossless round-trip. Signals: ScheduleItemResponseMapper, ScheduleItemResponseRoundTripTests, EnforceProperties normalization · paths: ErsatzTV.Core/Api/Scheduling/ · issues: #126, #207, #212 Mechanics: ScheduleItemResponseRoundTripTests

GET/POST/PUT /api/schedules/{id}/items return ScheduleItemResponseModel / ScheduleItemsResponseModel (ErsatzTV.Core/Api/Scheduling/), not the Application-layer ProgramScheduleItemViewModel hierarchy (One/Flood/Multiple/Duration subtypes). The polymorphic VM only described its base shape in OpenAPI, so the SPA couldn't see the subtype fields (issue #126). The flat DTO promotes every subtype field to a nullable top-level member — multipleMode, multipleCount (renamed from the VM's Count), playoutDuration, tailMode, discardToFillAttempts — mapped by pattern-matching the concrete VM in ScheduleItemResponseMapper (ErsatzTV.Application/ProgramSchedules/). Its mutation fields are named 1:1 with ScheduleItemRequest so a GET maps losslessly back to a PUT/POST (ScheduleItemResponseRoundTripTests is the release gate proving the fixed point). It also carries picker-hydration fields the editor needs: collectionName/smartCollectionName/…/playlistName, playlistGroupId (to preselect the playlist's group), per-filler names, watermarks / graphicsElements as NamedIdResponseModel lists, the computed name, and durationEstimate. GetProgramScheduleItemsHandler.EnforceProperties still rewrites StartType→Dynamic, Flood→One and Playlist/Rerun→PlaybackOrder None when ShuffleScheduleItems is on — that lossy normalization is deliberate and lives on the read side (documented + tested). New shared NamedIdResponseModel (ErsatzTV.Core/Api/) is the generic {id, name} embed for API responses. Issues #126/#207/#212.

2026-07-10 — Playout API mutations return 409 while the build lock is held (#215)

key: api.playout-build-lock-409 · status: active · since: 2026-07-10 · supersedes: none · superseded-by: none Rule: Every id-keyed playout/channel mutation endpoint checks IEntityLocker.IsPlayoutLocked(id) and returns 409 Conflict while a build is in-flight, mirroring Blazor's disabled-buttons behavior; reset-all stays 202 and silently skips locked playouts. Signals: ApiResults.ConflictProblem, PlayoutListItemResponseModel.IsLocked, advisory check-then-act · paths: PlayoutController.cs, ChannelController.cs · issues: #215, adversarial-reviewer#18 Mechanics: ApiResults.ConflictProblem

Blazor disabled per-playout Reset/Erase/Delete/Edit while a BuildPlayout was in flight (EntityLocker.IsPlayoutLocked, Playouts.razor + per-kind editors); the REST API had no equivalent, so a client could race an in-flight build with a destructive ExecuteDelete and leave a half-built playout. Adversarial-reviewer#18 promoted this to a #91-phase-(b) removal gate: after Blazor is deleted the invariant would vanish entirely.

Decision: enforce the invariant server-side on the API rather than re-implementing a live push channel. PlayoutController and ChannelController inject IEntityLocker; every id-keyed mutation — PUT /api/playouts/{id}, .../deco, .../alternate-schedules, .../templates, POST .../erase-items, .../erase-items-and-history, DELETE /api/playouts/{id}, and POST /api/channels/{channelNumber}/playout/reset — checks IsPlayoutLocked(id) first and returns 409 Conflict (ApiResults.ConflictProblem, new shared helper mirroring NotFoundProblem) while the build lock is held. The PUTs are gated too (not just the destructive ops): the target invariant is "no mutation during a build", matching Blazor's edit-disable.

• The guard is advisory check-then-act, not mutual exclusion — same posture as Blazor's disabled buttons. A BuildPlayout already sitting in the worker queue can take the lock a few milliseconds after the check passes, so the original race is narrowed, not eliminated; consequences remain self-healing (the next rebuild corrects a half-mutated playout). True prevention — having each mutation acquire the playout lock for its duration — was deliberately not taken: LockPlayout publishes PlayoutUpdatedNotification (UI churn per mutation) and would make mutations block builds, a semantics change out of scope for restoring Blazor parity.

• reset-all is deliberately NOT gated — it stays 202. ResetAllPlayoutsHandler already silently skips locked playouts, which matches Blazor and the handler semantics; a fire-and-forget bulk enqueue always accepts.

• SPA mirrors the lock via data, not a push channel — PlayoutListItemResponseModel gains an IsLocked bool (set from IsPlayoutLocked in the controller's list projection). The playouts screen disables Reset/Erase/Erase-and-history/Delete for a locked row and shows a "Building…" Badge; on a 409 from any mutation it surfaces the error and calls query.refresh() so the row picks up the flag. No new polling was added (the existing 30s channel-state poll is unchanged).

Precedent for the 409 shape: TraktController (left as-is with its own private ConflictProblem() to keep the diff small). Convention recorded in api-conventions.md §3a.

2026-07-11 — Schedules SPA editor: draft/explicit-Save over instant-persist; Copy includes multi/smart/rerun; shuffled-GET normalization preserved

key: spa.schedules-editor-draft-save · status: active · since: 2026-07-11 · supersedes: none · superseded-by: none Rule: The schedules SPA editor mutates a local draft and flushes one explicit Save (PUT /api/schedules/{id}/items) instead of instant-persisting each action; Copy deep-copies all source references (fixing a Blazor omission); the shuffled-schedule GET's EnforceProperties lossy normalization is preserved and mirrored in the SPA's option lists. Signals: draft/dirty guard, navigationGuard.ts, copyDraftItem, EnforceProperties · paths: web/src/screens/SchedulesScreen.tsx, web/src/schedules/, docs/spa-conventions.md §8 · issues: #207 Mechanics: docs/spa-conventions.md §8

The ChicoryTV schedules editor (web/src/screens/SchedulesScreen.tsx + web/src/schedules/, issue #207) rebuilds the schedule-item lineup to full mutation parity with the legacy Blazor editor. Three deliberate decisions:

(a) Draft model with one explicit Save, replacing instant-persist. All add/edit/copy/remove/ reorder mutate a local draft list only; a single Save issues one PUT /api/schedules/{id}/items (the replace endpoint). This is intentional because that PUT is destructive server-side — it deletes and recreates every item row (new ids) and triggers playout rebuilds — so batching edits into one flush (vs. the old per-action POST/DELETE/PUT) minimizes churn and gives the user a Discard/dirty affordance. On 422/network error the draft is kept and the error surfaced; on success the draft is replaced with the server response. A Discard action and a dirty guard (native confirm() on schedule-switch + in-app nav via navigationGuard.ts, plus a beforeunload listener) protect the draft. See docs/spa-conventions.md §8. This retires the old inline ScheduleScreen in App.tsx and its instant-persist add/delete/reorder tests.

(b) Copy item deep-copies ALL source references, including multi/smart/rerun collections. Blazor's CopyItem omitted the multi-collection / smart-collection / rerun-collection references when duplicating an item (copying only the plain collection/media-item/playlist refs) — a latent bug. The SPA's copyDraftItem (web/src/schedules/itemRules.ts) copies every source field + display name, so copying a MultiCollection/SmartCollection/Rerun item preserves its source. Deliberate deviation fixing the Blazor omission.

(c) The shuffled-schedule GET normalization (EnforceProperties) is preserved lossiness, matching Blazor. When a schedule has ShuffleScheduleItems, GET .../items still rewrites startType→Dynamic, Flood→One, and Playlist/Rerun playbackOrder→None (and zeroes discardToFillAttempts for non-random Duration items). The SPA does not fight this — it hides the Fixed start type and Flood playout mode from the option lists (and disables the reorder arrows) for shuffled schedules, mirroring Blazor, so a GET→edit→PUT round-trip stays consistent with the server's read-side normalization. Issue #207.

2026-07-11 — Channel editor: bare-create entry point + external-logo mutual exclusion (#212)

key: spa.channel-editor-create-logo · status: active · since: 2026-07-11 · supersedes: none · superseded-by: none Rule: Bare-channel create is a "New blank channel" action on the channels list (reusing Blazor's add-mode defaults) that navigates into the full editor, and an external logo URL always wins over an uploaded logo, matching ChannelEditViewModel precedence. Signals: ChannelEditor.razor add-mode defaults, ArtworkContentTypeModel.isExternalUrl, EMPTY_LOGO · paths: web/src/App.tsx, ChannelEditScreen.tsx · issues: #212 Mechanics: ChannelEditScreen.tsx

Two Blazor-parity decisions closing the channel-editor gaps (ChannelEditor.razor + ChannelEditViewModel):

1. Bare-channel create lives on the channels list, not a form-first route. Blazor's /channels (no Id) is a full add form; the SPA instead adds a "New blank channel" action next to "Add Channel" on ChannelsScreen (web/src/App.tsx) that POSTs CreateChannelRequest with Blazor's computed add-mode defaults ((max existing int-parsed channel number) + 1, name: "New Channel", group: "ErsatzTV", ffmpegProfileId = GET /api/settings/ffmpeg's defaultFFmpegProfileId, streamingMode: "TransportStreamHybrid", isEnabled/showInEpg: true, every other field at its C# default(T) — see ChannelEditor.razor's else branch for the source of truth) directly, then navigates to /app/edit-channel/{id} for the rest of the fields. This is a deliberate equivalent, not a parity gap: it reuses the existing full editor instead of duplicating its ~20 fields into a second form. "Add Channel" (/app/new-channel, the library-to-lineup ChannelBuilder flow) is unrelated and untouched.
2. External logo URL wins over an uploaded logo, mirroring ChannelEditViewModel.ToUpdate/ToCreate. The channel's logo is ArtworkContentTypeModel { path, contentType, isExternalUrl }; on hydration, isExternalUrl: true populates a separate "External logo URL" field and the uploaded-logo draft state is treated as empty (EMPTY_LOGO = { path: '', contentType: '' } in ChannelEditScreen.tsx) so the two never disagree. On submit, a non-blank URL always wins: logo: { path: url, contentType: '' }, exactly matching ExternalLogoUrl's precedence in the C# view model. Uploading a file clears the URL field (the last-set field wins, Blazor parity via UploadLogo's _model.ExternalLogoUrl = null). The URL is validated as http(s) client-side before save is enabled (Blazor has no equivalent validation; added because the field is free text with no server-side format check surfaced to the SPA).

Also landed with #212: preferredAudioLanguageCode/preferredSubtitleLanguageCode, musicVideoCreditsTemplate, and streamSelector moved from free-text Inputs to Selects fed by GET /api/languages / /api/channels/music-video-credits-templates / /api/channels/stream-selectors. Each keeps the channel's currently-stored value selectable even if it's absent from the reference list (optionsKeepingCurrent in ChannelEditScreen.tsx) so loading an existing channel never silently changes the value out from under an unmanaged language code or a template/selector file removed from disk since save.

2026-07-11 — EntityLocker: atomic flags + single-owner release discipline, no owner tokens (#231)

key: locking.entitylocker-atomic-flags · status: active · since: 2026-07-11 · supersedes: none · superseded-by: none Rule: EntityLocker uses Interlocked.CompareExchange-guarded atomic flags plus a documented single-owner-release discipline (no owner tokens/leases); Unlock* on an already-unlocked slot returns false and logs a Warning rather than throwing. Signals: six bool→int flags, TraktController.EnqueueWithTraktLock, unlock: last tail pattern · paths: ErsatzTV.Infrastructure/Locking/EntityLocker.cs, IEntityLocker · issues: #231, #232, #234, adversarial-reviewer#20/F5 Mechanics: ErsatzTV.Infrastructure/Locking/EntityLocker.cs

EntityLocker (process-wide singleton, ErsatzTV.Infrastructure/Locking/EntityLocker.cs) is the advisory "operation on entity X is in progress" mutex layer. Adversarial review (#20/F5, →#231) found three defects: six plain-bool flags with a non-atomic check-then-set (two threads could both acquire and both return true), tokenless Unlock* letting any caller release another owner's lock (e.g. BuildPlayoutHandler ignored LockPlayout's return then unconditionally unlocked in finally), and one batch taking a single LockLibrary released after the first of two enqueued scan units (so the second ran unlocked).

Model chosen: tokenless atomic flag + documented single-owner release discipline. The six bools became ints guarded by Interlocked.CompareExchange (0/1), so Lock*'s bool return is now a reliable "this call won the transition" signal and the change event fires exactly once per transition. The contract (XML-doc'd on IEntityLocker): a true from Lock* confers ownership of exactly one release — performed either in the acquiring scope (finally, gated on the captured bool) or by the single designated releaser the acquirer hands off to (the consumer of the message enqueued while holding the lock, with a compensating unlock if the enqueue throws — the established TraktController.EnqueueWithTraktLock / scheduler unlock: last tail pattern). Callers must never release a lock they did not acquire. Unlock* on an already-unlocked slot returns false, fires no event, and logs a Warning — the loud tripwire for double-release bugs; it does not throw or Debug.Assert, because an advisory flag must stay safe to release in finally paths. The three ConcurrentDictionary-backed kinds (Library/Playout/RemoteMediaSource) were already atomic (TryAdd/TryRemove) and kept their semantics (the redundant ContainsKey pre-checks were dropped as tidy-up); the interface signature is unchanged across its ~40 call sites.

Rejected: owner tokens/leases — the acquirer and releaser for Library/Trakt/Plex/Collections locks are different code correlated only by entity id across in-memory Channel<T> queues, so a token would have to travel inside ~8 background-request message types for a defect that discipline plus the now-trustworthy atomic return value already prevents. Counted/reentrant locks — wrong semantics: these are exclusive in-progress flags; two holders is the failure mode, not a feature. Call-site fixes this model prescribes land separately: #232 (scan lifecycle — enqueue only after a successful lock, compensating unlock on enqueue failure, one release per acquisition in batches) and #234 (BuildPlayout/subtitles gate their finally unlock on the captured acquire result).

2026-07-11 — Media-source management REST write API + SPA (#202)

key: media.source-mgmt-write-api · status: active · since: 2026-07-11 · supersedes: none · superseded-by: none Rule: Media-source management (local/Plex/Jellyfin/Emby) is a REST write API + SPA under /app/libraries/*, wrapping existing MediatR commands 1:1 with no new commands or DB migration; connection GETs never leak a stored apiKey, and each PUT-replace family's identity contract is documented per-family (not assumed uniform). Signals: RemoteConnectionResponseModel {hasApiKey}, per-family identity contracts, Plex pin-flow polling, EntityLocker non-owner-token discipline · paths: LocalLibrariesController, Plex|Jellyfin|EmbyMediaSourcesController · issues: #202, #197, #231 Mechanics: docs/handoffs/ session record, issue #202

Replaced the Blazor /media/sources/{local,plex,jellyfin,emby}/... pages (14 routes) with SPA screens under /app/libraries/* over new write controllers (LocalLibrariesController, Plex|Jellyfin|EmbyMediaSourcesController), wrapping existing MediatR commands 1:1 (no new commands, no DB migration). Full design + adversarial-review reconciliation: docs/handoffs/ session record and issue #202. The design surfaced and fixed several pre-existing Application/Infrastructure bugs newly reachable from a programmatic client; each is recorded here because it changes documented behavior, not just adds a route.

Secure apiKey contract (Jellyfin/Emby connection). The connection GET (RemoteConnectionResponseModel) returns { address, hasApiKey } — the stored key never leaves the server, closing a leak where the old design would have served the raw key from an unauthenticated GET under any-origin CORS. On the connection PUT, a blank/omitted apiKey means retain the existing key; a non-blank value sets a new one; the key is required on first connect (no existing secret) → 422. Rationale: GETs aren't behind X-Api-Key (ApiKeyAuthorizationFilter only guards mutating verbs), so a secret-bearing GET is a real exposure regardless of how obscure the route is. Stated explicitly as an input to #197 (the planned read-side-auth review for secret-bearing GETs) — #197 should treat "does any GET return a credential" as one of its checks, not just this one instance.

Three list-replace identity contracts, not one uniform one. An earlier draft assumed a single "Id<1=add / missing=delete / id-preserved" contract across all three PUT-replace families; source inspection proved that false for two of them:

• Remote library sync preferences (PUT .../{id}/libraries) — the command carries no source id and the handler toggles only the ids present in the body; a row absent from the request is left untouched, not deleted (libraries are sync-discovered, never created via this PUT, so there are no Id=0 adds either). The controller validates the submitted id set against Get{Family}LibrariesBySourceId(id) (422 on any id not owned by the route's source — closes a cross-source hole). Identity is not stable across a disable: Disable{Family}LibrarySync removes and re-adds the row with a fresh id, so the SPA keys its draft to (name, mediaKind), never to Id, and refetches after every save (the PUT returns the reloaded list).
• Path replacements (PUT .../{id}/path-replacements) — id-based (existing Id=update, Id<1=add, absent=delete) as documented, but the repo UPDATE SQL had no source-id predicate (WHERE Id = @id, no AND {Family}MediaSourceId = @id), so a PUT to source A could silently overwrite source B's row with the same numeric id. Fixed with a handler-level ownership guard (reject any incoming positive id not in this source's current set → 422, no partial mutation) and the repo SQL predicate itself (defense-in-depth for any other caller of that repo method).
• Local library paths (PUT /api/libraries/local/{id}) — identity is the normalized path string (full path, trailing-separator/case-insensitive), not Id; Id in the request is advisory. Renaming a path is delete-old+add-new under the hood (its LibraryPath.Id changes). Kept as-is (matches the entrenched, tested Blazor behavior and how the SPA edits by value); not rewritten to id-based identity, which would be a bigger, riskier change out of #202's scope.

Plex pin-flow as REST: poll until the lock releases, exception-safe non-handoff unlock. The SPA polls GET /api/media-sources/plex rather than a per-pin status resource (no pin-addressable server state exists to expose; SSE/push was already rejected, 2026-07-09). Polling contract is isLocked && !isAuthorized = waiting on the user; isLocked && isAuthorized = finalizing (discovering servers — do not stop here, the server list is still empty); !isLocked && isAuthorized = success; !isLocked && !isAuthorized = timed out/abandoned. This required fixing a latent lock-leak bug: TryCompletePlexPinFlowHandler threw OperationCanceledException on its 2-minute timeout instead of returning false, and nothing unlocked on that path — an abandoned sign-in wedged the Plex lock until restart or manual sign-out. Fix releases UnlockPlex() on the timeout-throw, a poll-exception, and an enqueue-exception — but deliberately not in an unconditional finally: on success the lock is handed off to SynchronizePlexMediaSources, the sole releaser after server discovery; a blanket finally would double-release and release before discovery completes, re-opening the same race the fix closes. This is the same non-owner-token discipline as the #231 EntityLocker model (2026-07-11 entry above), applied to the pin-flow's handoff-vs-terminal distinction specifically.

404 comes from the controller pre-check, not the handler. Apply/ToEitherAsync both .Join() errors, which flattens any NotFoundError inside a joined Validation down to a plain 422. So every id-taking endpoint's real 404 is a controller-side pre-check (Get...ById(id)-is-None → ApiResults.NotFoundProblem, the TemplateController.DeleteGroup pattern), not a handler-level conversion — converting the joined validators to NotFoundError would be dead code, since the join discards the distinction anyway. This is check-then-act (a delete racing between the pre-check and the command falls through to the handler's own 422, not a 404); accepted and tested against the actual runtime error type rather than a hoped-for handler 404.

"Scan All" dropped, not implemented. The disabled SPA header button on the libraries hub was speculative UI with no Blazor equivalent (Libraries.razor only ever supported per-library scan). Removed rather than backed with a new bulk-scan endpoint; per-library scan (#232) and the new per-source refresh-libraries endpoints (P8/J9/E9) cover the real capability set.

App-owned popstate for guarded sub-path routes. LocalLibraryEditScreen and the other /app/libraries/* editors are the first screens to both register a dirty-navigation guard and track their own sub-path pathname — the combination spa-conventions.md §8 had flagged as unvalidated. React commits child passive effects before parent ones, so a sub-path wrapper that self-registers popstate would fire (and switch sub-screen) before App's guard-restore listener could veto. Resolution: App owns popstate centrally for the libraries route and only pushes an approved sub-path down to the wrapper (which no longer self-registers popstate); on a vetoed pop App re-pushes the pre-pop URL and the wrapper never sees the rejected path. This is scoped to the libraries route only (gated on activeRoute === 'libraries') so unguarded sub-path routes (Playouts, Media) stay byte-identical. See spa-conventions.md §2/§8 for the updated exemplar list and the resolved caveat text.

2026-07-11 — Legacy→SPA redirect matcher: exact map + ordered segment-template patterns (#204)

key: spa.legacy-redirect-matcher · status: active · since: 2026-07-11 · supersedes: none · superseded-by: none Rule: LegacyUiRedirects.TryGetRedirect is a two-tier matcher — an exact OrdinalIgnoreCase Map (Tier 1) then an ordered segment-template pattern list (Tier 2, first-match-wins) — collision-free by construction, with a guard invariant that no rule may prefix-match /api, /artwork, /docs, /openapi, /iptv, /app, or /media/sources. Signals: {id} strict-positive-integer token, {any} token, AppendQueryString merge · paths: ErsatzTV/LegacyUiRedirects.cs · issues: #204 Mechanics: LegacyUiRedirects.TryGetRedirect, AppendQueryString

LegacyUiRedirects.TryGetRedirect grew from a single exact-path dictionary to a two-tier matcher behind the unchanged (PathString, out string) signature. Tier 1 is the existing OrdinalIgnoreCase Map (now 52 entries — the parameterless (A)/(B) routes plus the (E-base) browse roots whose targets carry ?kind=…). Tier 2 is an ordered IReadOnlyList<PatternRule> of 36 segment-template rules ((C)/(C2)/(D)/(E-page)), consulted only on a Tier-1 miss; declaration order is match order (first-match-wins).

Template tokens are minimal: {id} matches a strict positive integer (int.TryParse(seg, NumberStyles.None, InvariantCulture, out id) && id > 0 — rejects signs, whitespace, separators, 0, negatives, and overflow like 999999999999; the raw segment text, e.g. 007, is substituted, not re-formatted); {any} matches any non-empty segment and is dropped (only /playouts/add/{any}); everything else is a literal compared OrdinalIgnoreCase. The request path is split with StringSplitOptions.None and empty segments are rejected (load-bearing: so /channels//5 cannot match /channels/{id}); templates themselves use RemoveEmptyEntries. The existing single-trailing-slash normalization runs before both tiers, so /channels/5/ matches.

The set is collision-free by construction — exact-before-pattern plus strict numeric {id} means no two tiers/rules can match the same path. Guard invariant (comment + Map-keys meta-test): no Tier-1 key or Tier-2 template may begin with /api, /artwork, /docs, /openapi, /iptv, /app, or /media/sources; rules are always full, specific templates — never prefix wildcards (a bare /media/{any} rule is forbidden). The blazor branch does not prefix-guard /api|/artwork|/docs| /openapi, so the matcher's specificity is part of their protection.

Query-string merge: the incoming request query is now merged into the target via a new public AppendQueryString(target, QueryString) helper (one-line Startup change: context.Request.PathBase + LegacyUiRedirects.AppendQueryString(target, context.Request.QueryString)). A target that already carries ? (the ?kind=… browse roots) is &-joined instead of producing a malformed double ?; plain targets keep verbatim-append behavior byte-for-byte. A duplicated key after a merge (?kind=movies + incoming ?kind=shows) is first-wins in the SPA (URLSearchParams.get returns the first value) — acceptable. Extracting the merge into LegacyUiRedirects keeps it unit-testable without a TestServer while preserving the PathBase re-application invariant the Startup source-text test protects.

Rejected: regex pairs (harder to audit for the /api//artwork greediness invariant, noisier tests, no benefit — every parameterized route here is "fixed segments + one variable segment"); ASP.NET TemplateMatcher/RouteMatcher (pulls routing machinery into a static helper for 36 rules); a single unified rule list (loses the O(1) dictionary hit for the ~52 exact routes that dominate real traffic). No /api change, no OpenAPI regen, no SPA change.

2026-07-11 — Pre-removal Blazor rollback tag blazor-final (#205)

key: blazor.rollback-tag · status: active · since: 2026-07-11 · supersedes: none · superseded-by: none Rule: The commit immediately preceding the Blazor-removal merge is tagged blazor-final (not a v* tag, so it doesn't trigger a prod release build) as the documented rollback/restore path. Signals: git tag -a blazor-final, ersatztv:blazor-final test-image restore path · paths: none · issues: #205 Mechanics: git tag blazor-final

Removal-gate item #205: the removal PR deletes both the Blazor reference implementation and the /system/health escape hatch, so a post-deletion parity gap would otherwise be an archaeology exercise (guessing which release tag still matches main minus Blazor). Decision + procedure, to run as the first action of the Step 2 deletion PR merge (not before — main moves until then):

1. On the main commit immediately preceding the removal merge (the last commit that still contains ErsatzTV/Pages/**), cut an annotated tag and push it: git tag -a blazor-final -m "Last commit with the legacy Blazor Server UI (pre-#91-phase-b removal)" then git push origin blazor-final. The tag name is blazor-final (not v*) so it does not trigger the v* prod-release build in .gitea/workflows/docker-build.yml.
2. Restore path (if a gap surfaces post-removal): git checkout blazor-final → docker build -f docker/Dockerfile -t ersatztv:blazor-final . → pin the test container to that image while the gap is fixed forward on main. Alternatively git revert the single deletion merge commit (keep the deletion as one squash/merge commit specifically to make this a one-liner).
3. Document the tag + restore path in the removal PR body; update this entry with the tag's commit sha when cut.

Not cut this session — main still carries Blazor and will advance before the removal PR.

2026-07-11 — Async-op API contract normalization + playout build observability + F9 scan endpoints (#235)

key: api.async-op-contract · status: active · since: 2026-07-11 · supersedes: none · superseded-by: none Rule: Queue-triggering /api/* endpoints normalize onto one contract — 202 Accepted (queued), 404 (missing entity), 409 (lock held), 422 (domain precondition) — with Trakt as the reference implementation; playout list/detail GETs also carry an isLocked observability flag as the HTTP-observable substitute for a live push channel. Signals: QueueShowScanResult, ResetAllPlayoutsResponseModel, MaintenanceController.EmptyTrash/CleanArtwork · paths: LibrariesController.ScanShow, ChannelController.ResetPlayout, PlayoutController.ResetAll · issues: #235, adversarial-reviewer#20 F7/F8/F9, #232, #215 Mechanics: docs/api-conventions.md §3a/§3b

Reviewer#20 F7/F8/F9. Normalizes the queue-triggering /api/* endpoints onto one contract, closes the two F9 Libraries.razor parity gaps, and hardens the Trakt batch-lock lifecycle. Much of the F8 surface was already normalized by #232 (library scan → QueueLibraryScanResult 202/404/409/422) and #215 (per-id playout mutations + reset → 409 lock guard) — this issue finished the remaining outliers.

Normalized async-op contract (queue-triggering endpoints): 202 Accepted = work queued; 404 ProblemDetails = entity missing (controller pre-check); 409 ProblemDetails = lock held (the running job, or a mutation racing it — §3a/§3b); 422 ProblemDetails = domain precondition (sync disabled / unsupported / start failed). Trakt was the reference implementation. Changes made:

• MaintenanceController.EmptyTrash — error path 500 text/plain → 404/422 ProblemDetails (ToErrorResult).
• MaintenanceController.CleanArtwork — silent 200 → 202 (fire-and-forget enqueue). No SPA consumer.
• LibrariesController.ScanShow — conflated 400 {error} → 202/404/409/422 via a new QueueShowScanResult enum (6 outcomes incl. an honest ScanFailed→422, distinct from Unsupported).
• ChannelController.ResetPlayout — 200 → 202 (queue-triggering; 404/409 unchanged).
• PlayoutController.ResetAll — 202 (no body) → 202 + ResetAllPlayoutsResponseModel reporting queuedPlayoutIds / skippedLocked / skippedUnsupported (replaces the silent skip; still 202, still skips locked/ExternalJson by design per §3a — now it reports what it skipped).
• TroubleshootController.TroubleshootPlayback — bare body-less NotFound() → 404/422 ProblemDetails with distinguishing detail. Status codes the SPA HLS player depends on were preserved — verified HlsPlayer.tsx never branches on this endpoint's status (playback state comes from the separate /api/troubleshoot/playback/status poll); only the error body was enriched.

Playout build observability: the list endpoint (GET /api/playouts) already stamped isLocked + BuildStatus on PlayoutListItemResponseModel (#215); this issue adds isLocked to the single-playout GET /api/playouts/{id} (PlayoutResponseModel), so the detail poll surface carries the §3a lock flag too. No dedicated GET /api/playouts/{id}/status push channel was added — the flag on the existing GETs is the HTTP-observable substitute for Blazor's live lock event, matching the GET /api/trakt/status precedent.

F9 parity endpoints (the Libraries.razor deletion gate — #202 did NOT close these):

• Deep scan: POST /api/libraries/{id}/scan gains ?deep=false, threaded through QueueLibraryScanByLibraryId(LibraryId, DeepScan=false) into ForceSynchronize{Plex,Jellyfin,Emby}LibraryById(id, deep) (was hardcoded false). Non-breaking: existing callers omit it.
• External-collections scan: new POST /api/media-sources/{plex|jellyfin|emby}/{id}/scan-collections?deep=false on the three #202 media-source controllers, dispatching Synchronize{X}Collections(id, ForceScan:true, deep). Each pre-checks source existence (404), acquires the per-source collections lock (Lock{X}Collections() — the lock is the running scan, so a false = 409), then enqueues and returns 202; the controller compensating-unlocks in a catch if the enqueue throws (§3b), and ScannerService releases in its finally. Thin SPA clients shipped (scanLibrary(id, deep), scanCollections); the SPA deep-scan / collections buttons are the removal PR's remaining parity work (parity doc §5).

F7 Trakt batch-lock leak fix: the global Trakt lock was released only when the terminal batch message (Unlock: true) was processed; a WorkerService shutdown/cancellation before that message leaked the lock permanently (subsequent Trakt ops 409 until restart — same class as #231/#233/#234). Fix: WorkerService now releases the Trakt lock in a finally on read-loop exit if still held. Non-vacuous regression test proven against an inverted-condition control.

Accepted-by-design (per the issue's decision-record ask): the worker's channels are unbounded and there is no shutdown drain — messages still queued at process exit are dropped. This is acceptable because the entity locks are in-memory singletons that die with the process, so a dropped message can't strand a lock across restarts (the F7 finally covers the within-process shutdown-break leak, which is the only way a lock outlives its batch while the process keeps running). Adding a bounded-channel backpressure / graceful drain is out of scope and would not fix a correctness bug.

2026-07-11 — Post-commit side effects run on CancellationToken.None (generalized from #251 to #254)

key: api.postcommit-cancellation-none · status: active · since: 2026-07-11 · supersedes: none · superseded-by: none Rule: Once a mutation commits, its entire compensating side effect (enqueues, publishes, reindexes, cache refresh, and any post-commit lookup gating one of those) runs on CancellationToken.None so a late client disconnect can't half-abort an already-committed change. Signals: WriteAsync enqueue, mediator.Publish, search-index reindex · paths: docs/api-conventions.md §7b, MediaCollections/, ProgramSchedules/, Playouts/, Channels/ handlers · issues: #251, #254, adversarial-reviewer#22 Mechanics: docs/api-conventions.md §7b

Audit #22 (adversarial-reviewer) found ~20 command handlers threading the request cancellationToken into work that runs after SaveChangesAsync commits — the post-commit WriteAsync enqueue that rebuilds/refreshes the affected entity, mediator.Publish, search-index reindex, cache refresh. A late HTTP-client disconnect cancels that token, so the already-committed mutation throws on the way out and silently drops its side effect (the playout rebuild is never queued → the persisted edit never takes visible effect until a manual Reset). #251 fixed this for the deco handlers; #254 generalizes the policy across the codebase.

Decision. Once a mutation has committed, the entire compensating side effect — enqueues, publishes, reindexes, cache refreshes, and any post-commit lookup that gates one of those enqueues — runs on CancellationToken.None. The commit is the point of no return; past it the side effect must not be half-abortable. Full convention + the two boundaries in docs/api-conventions.md §7b.

Scope of the #254 sweep (this PR). Swept the single-SaveChanges handlers under MediaCollections/, ProgramSchedules/, Playouts/, Channels/ (20 handlers). Deliberately excluded:

• BuildPlayoutHandler — a background/worker handler; its token is the worker shutdown token, not a client-disconnect token, so its downstream enqueues correctly honor cancellation.
• UpdateFFmpegSettingsHandler + the two Configuration/ settings handlers — they commit via several sequential IConfigElementRepository.Upsert calls with an interleaved enqueue; "when is it committed" is a partial-commit-under-cancellation question broader than the clean single-SaveChanges F4 pattern. Left for a separate follow-up.
• Response-projection reloads (ReplaceProgramScheduleItemsHandler / AddProgramScheduleItemHandler post-commit graph reload that builds the returned view model) keep the request token — a cancelled response after a durable commit + None-enqueue loses nothing.
• Handlers a no-token WriteAsync() already makes behaviorally correct (default == None) were left alone (explicit-None there is cosmetic).

Also folded in the two other #254 items on the same handlers: the channel-guide {number}.xml delete in DeleteChannelHandler/DeletePlayoutHandler now routes through IFileSystem.File.Delete (observable under MockFileSystem) before the commit (a post-commit delete orphans the xml on a crash; the guide xml is regenerable on demand, so a pre-commit delete is the safe ordering), and ReplacePlayoutAlternateScheduleItemsHandler now rejects an empty item list in the handler (not only at the controller pre-guard) so a direct caller can't trip the Max()-on-empty crash.

Coordination note for #253 PR2–PR4. Those PRs add Version++ (pre-commit) to the mutating handlers of the versioned aggregates — several of which this sweep also touched (post-commit token, a different line region). Low git-conflict risk, but merge main in and expect to see the CancellationToken.None convention already present on the post-commit enqueues.

2026-07-12 — External-collections scans get an authoritative status surface (#271); the SPA timeout is retired

key: scan.collections-scan-status · status: active · since: 2026-07-12 · supersedes: none · superseded-by: none Rule: GET /api/v1/media-sources/collections-scan-status reports a family-global (not per-source), boolean-only active-scan set read from IEntityLocker; the SPA reconciles authoritatively against it (with a grace-tick helper) instead of a fixed client-side timeout. Signals: CollectionsScanStatusResponseModel, useCollectionsScan, pruneGraceExpiredPending, COLLECTIONS_PENDING_TIMEOUT_MS removed · paths: MediaSourcesController.GetCollectionsScanStatus · issues: #271 Mechanics: GET /api/v1/media-sources/collections-scan-status

External Collections rows stay client-derived. The SPA derives them from GET /api/v1/media-sources: remote sources expose only sync-enabled libraries, so a non-empty libraries list is equivalent to Blazor's Libraries.Any(ShouldSyncItems) filter. No second listing endpoint or fetch is needed.

The first scan-button implementation used a bounded optimistic timeout because collections locks had no HTTP mirror. #271 replaces that temporary ceiling with the authoritative status contract below.

Decision 1 — one family-global status endpoint, reading IEntityLocker. New GET /api/v1/media-sources/collections-scan-status (MediaSourcesController → GetCollectionsScanStatus handler) returns one CollectionsScanStatusResponseModel { family } entry per media-source family (plex/jellyfin/emby) whose collections lock is currently held, and only for active ones — the direct counterpart to GET /api/v1/libraries/scan-status. It reads IEntityLocker.Are{X}CollectionsLocked() (the lock is the running scan — the scan-collections controllers acquire it before enqueueing and the scanner releases it on completion), analogous to how the library endpoint reads IScannerProxyService.GetActiveScans(). Two deliberate shape differences from libraries: (a) family-global, not per-source — the collections lock takes no source id (LockPlexCollections()), so an entry means every source of that family is scanning, matching Blazor's all-rows-disabled behavior (per the PR #272 review note); (b) no percent — collections scans expose only a boolean lock, not progress.

Decision 2 — the SPA reconciles authoritatively; the fixed timeout is removed. useCollectionsScan now polls the new endpoint (seeding on mount, so a scan already running when the screen opens disables the buttons immediately — the old timeout couldn't) and reconciles optimistic pending against the active-family set using the same pruneGraceExpiredPending grace-tick helper the library hook uses (now generic over the pending key type). A row shows "Scanning" when its family is in the active set or it has a still-in-grace optimistic pending key. The grace window is kept (not the old wholesale timeout) to absorb the click→observed-active lag and the fast-scan-between-polls race — the same bounded-pending discipline #232/#230 established for library scans. COLLECTIONS_PENDING_TIMEOUT_MS is gone.

2026-07-11 — Blazor Server UI removed (#91 phase b)

key: blazor.ui-removed · status: active · since: 2026-07-11 · supersedes: none · superseded-by: none Rule: The legacy Blazor Server UI (Pages/, Shared/, ViewModels/, Validators/, MudBlazor + 8 other packages, Blazor Startup wiring) is fully deleted now that the SPA has parity; the legacy MapWhen branch is kept only for controllers/docs/OpenAPI/LegacyUiRedirects, and the catch-all fallback 302s any unmatched non-api/artwork/docs/openapi path to /app. Signals: blazor-final rollback tag, #206 auth-posture sign-off, forbidden-prefix guard lifted for /media/sources · paths: ErsatzTV/Pages/**, ErsatzTV/Shared/**, ErsatzTV/ViewModels/**, ErsatzTV/Validators/** · issues: #91, #145, #151, #152, #153, #155, #202, #207, #212, #213, #235, #204, #206, #25 Mechanics: Startup.cs MapFallback, LegacyUiRedirects.cs

The #91 phase (b) removal PR deletes the legacy Blazor Server UI now that the ChicoryTV SPA has parity (all gates cleared: #145, #151/#152/#153/#155, #202, #207, #212/#213, #235 F9). The SPA is the only UI.

Deleted. ErsatzTV/Pages/** (all .razor, incl. _Host.cshtml, FragmentNavigationBase.cs, MultiSelectBase.cs), ErsatzTV/Shared/** (all .razor + _Favicons.cshtml), ErsatzTV/ViewModels/** (39 Blazor edit-form VMs), ErsatzTV/Validators/** (10 Blazor edit-VM FluentValidation validators), App.razor, _Imports.razor, ErsatzTV/Locals/Shared/** + ErsatzTV/Locals/Pages/** (Blazor localization resx — ErsatzTV/Locals/Resources.* is KEPT), ErsatzTV/wwwroot/css/** (site.css), ErsatzTV/wwwroot/lib/** (jquery, jqueryui, sortablejs, hls, media-chrome, roboto), libman.json, and ErsatzTV.Tests/Pages/MultiSelectBaseTests.cs.

9 packages pruned (from both Directory.Packages.props and ErsatzTV/ErsatzTV.csproj; each verified to have zero remaining consumers after the Blazor deletion): MudBlazor, Heron.MudCalendar, Blazored.FluentValidation, BlazorSortable — unambiguous Blazor UI; MediatR.Courier.DependencyInjection — ICourier was consumed only by the deleted pages, and the app's mediator.Publish notification path is plain MediatR (unaffected by the AddCourier removal); Markdig, HtmlSanitizer, Chronic.Core, NaturalSort.Extension — verified zero non-Blazor consumers post-deletion.

Startup surgical reduction. Removed AddRazorPages (+AuthorizeFolder("/")), AddServerSideBlazor, AddMudServices, AddSortable, AddCourier, the Blazor-attached UseAuthentication/UseAuthorization, MapBlazorHub, and MapFallbackToPage("/_Host"). The former "blazor" MapWhen branch (lambda param renamed blazor→legacy) is KEPT — it still co-hosts MapControllers(), /docs (Scalar), dev MapOpenApi(), and the LegacyUiRedirects middleware. MapFallbackToPage("/_Host") is REPLACED by a catch-all endpoints.MapFallback(...) that 302-redirects any unmatched path to PathBase + "/app" EXCEPT paths under /api, /artwork, /docs, /openapi (those get a genuine 404, per #204's design). KEPT (not removed): the OIDC/JWT/API-key SERVICE registrations (inert unless configured; real auth is #197), ConditionalIptvAuthorizeFilter (/iptv/*), and ApiKeyAuthorizationFilter (mutating /api/*) — per the #206 auth-posture sign-off (deleting the Blazor page challenged nothing beyond phase (a)).

LegacyUiRedirects. Added redirects for all 14 /media/sources/* routes → their /app/libraries/* SPA screens (7 Tier-1 exact + 7 Tier-2 {id} patterns; the last Section-2 rows in blazor-route-parity.md), and LIFTED the #204-era /media/sources forbidden-prefix guard (its Blazor pages were replaced by #202's SPA screens). The forbidden-prefix guard now covers only /api, /artwork, /docs, /openapi, /iptv, /app.

Also removed the now-dead ersatztv#25 razor-Sonar <NoWarn>S6966;S3267;…</NoWarn> line from ErsatzTV.csproj — those Sonar rules only needed suppression in .razor @code; on .cs they run at suggestion via .editorconfig, so removal is safe (closes part of #25's burn-down).

Rollback. The tag blazor-final was cut on the pre-removal main commit as the first step (see the 2026-07-11 "Pre-removal Blazor rollback tag blazor-final (#205)" entry above for the exact command + restore path). Not a v* tag → no prod release build.

2026-07-12 — Live-E2E is a required step for API write-path handler changes (#303)

key: release.live-e2e-required · status: active · since: 2026-07-12 · supersedes: none · superseded-by: none Rule: A PR that changes an API write-path handler must include a live-E2E pass (driving the real endpoint/screen and confirming the round-trip through a subsequent read), not only unit/characterization tests, and must state whether live-E2E ran or wasn't required. Signals: lazy LanguageExt Map blind spot, #229 finding · paths: docs/e2e-local.md, docs/api-conventions.md §7 · issues: #303, #229 Mechanics: docs/e2e-local.md

A PR that changes an API write-path handler (a POST/PUT/DELETE /api/* command that mutates state and reloads it through the read path) MUST include a live-E2E pass — driving the real endpoint or its SPA screen and confirming the mutation round-trips through a subsequent read — not only unit / characterization tests. Rationale: this class has a correlated blind spot unit and characterization tests share. A green fixed-point test passed while the write-path returned a production 500 because the handler returned a lazy LanguageExt Map the test never enumerated (#229; reload-through-read-path mechanics in api-conventions.md §7); the failure surfaces only when the result is materialised, which the SPA does and the test did not. Live driving is the only reliable net for it.

Non-write-path (pure-SPA/read-only) and docs PRs don't need it. The requirement is auditable, not silent: the PR/close comment states that live-E2E ran, or — for a non-write-path change — that it wasn't required (the same stated-exemption discipline as the review skip rubric). Recipe + "When live-E2E is required": docs/e2e-local.md. This formalizes the #229 lore bullet ("live E2E remains the only net for this class") into a standing convention.

2026-07-12 — TopBar primary-action button: wire creates, drop the rest (#238)

key: spa.topbar-primary-action · status: active · since: 2026-07-12 · supersedes: none · superseded-by: none Rule: The TopBar's primary-action "+" button renders only when the active route declares a non-empty primaryAction, is wired (via a shared usePrimaryAction hook) only on single-unambiguous-create-flow list screens, and is dropped everywhere else rather than left as a dead/no-op button. Signals: usePrimaryAction hook, ctv:primary-action event, dead-button class · paths: web/src/primaryAction.ts, docs/spa-conventions.md §10 · issues: #238, #229, #247, #295 Mechanics: web/src/primaryAction.ts, docs/spa-conventions.md §10

The shell TopBar rendered a prominent top-right primary-action button (Plus icon) for every screen, but only SchedulesScreen had ever subscribed to its ctv:primary-action event — so on every other screen the button was dead (either a labelled no-op like "Save Changes"/"Add Channel", or, for the ~10 routes whose primaryAction was '', a bare labelless "+"; the button rendered unconditionally). Issue #238 (from a #229 live-E2E finding, pre-existing since the TopBar's introduction).

Decision — the Plus-icon button is a "create new item" affordance; keep+wire it only where that fits:

• TopBar renders the button only when the active route declares a non-empty primaryAction (was: unconditional). This alone removes every empty-'' dead "+".
• WIRE (8 list screens with a single unambiguous create flow) via a shared usePrimaryAction(routeId, handler) hook (web/src/primaryAction.ts), each delegating to the same top-level create handler its in-body control uses (navigateToPath('/app/new-channel'), setEditing({kind:'new'}), navigateToPath('…/add'), etc.): channels, schedules (refactored onto the hook), multiCollections, rerunCollections, traktLists, fillerPresets, ffmpegProfiles, watermarks.
• DROP (primaryAction: '', no button) everywhere else, for one of four reasons: (1) the action isn't a create so the "+" is wrong and a correct in-body control already exists — editChannel (savebar), settings (savebar), guide (Jump to now), playouts (Reset all), logs/troubleshooting/blockPlayoutTroubleshooting (Refresh), playbackTroubleshooting (Play), yamlValidator (Validate); (2) ambiguous — collections (two create types behind tabs); (3) a silent no-op — builder ("Create Channel" is disabled until the form is valid), playlists (needs a group first); (4) semantically misplaced — dashboard (status page), libraries ("Scan" is per-library-row, no global target).

Why not wire everything (the SchedulesScreen precedent): the recon found every screen already carries a correct, disabled-state-aware, context-aware in-body control, and several banner actions are unreachable without refactoring handlers out from under early returns, or would render a silent no-op — reintroducing the very dead-button class #238 fixes. Wiring only the single-create-flow screens gives one explainable rule ("primary button = create a new item on a list screen") and needs no risky refactors.

Also fixed here: the apiKey route's primaryAction: 'Save key' + its description/comment were stale post-#295 (the screen displays the machine key + changes the local password; there is nothing to "save") — relabelled to reflect the #295 reality. Convention + hook documented in spa-conventions.md §10. The implicit route-label ⟺ screen-subscription coupling is the kind of thing #247 (shell extraction) will formalize; #238 keeps it a documented convention guarded by a data-driven App.test.tsx test over the URL-navigating create screens (a typo'd route id → the banner navigates nowhere → red). Refs #238 #247.

2026-07-13 — API versioning: the whole /api surface is mounted at /api/v1, additive-only after freeze (#286)

key: api.versioning-v1 · status: active · since: 2026-07-13 · supersedes: none · superseded-by: none Rule: The entire /api surface is versioned to /api/v1 uniformly (no unversioned corner); legacy unversioned callers are rewritten in-pipeline (not redirected) with Deprecation/Link/Sunset headers, and post-freeze /api/v1 is additive-only — a breaking change requires /api/v2. Signals: ApiVersionRewriteMiddleware, ApiRouteVersioningTests, RFC 8594 Deprecation header · paths: docs/api-conventions.md §1/§9 · issues: #286, #197 Mechanics: ApiRouteVersioningTests, docs/api-conventions.md §1/§9

The #197 cold review's C1 BLOCKER: /api/* was entirely unversioned (info.version was cosmetic), so the first breaking change would silently break the SPA and any external/MCP client with no negotiation path. This is the Phase-2 contract-freeze gate — versioning can't be added compatibly after the contract ossifies, so it lands before freeze.

What changed. Every route under /api was swept to /api/v1 — all 251 controller route attributes, the ~24 Location-header literals, the scanner callback URL (CallLibraryScannerHandler.GetBaseUrl), and the Startup request-log path literal. This is uniform: the machine JSON API, the browser-session auth surface (/api/v1/auth/*, still IgnoreApi), the internal loopback callbacks (/api/v1/scan/*) and the scripted-build surface (/api/v1/scripted/*) are all versioned, so there is no unversioned corner and the compat rewrite needs no exclusion list. The OpenAPI v1.json (160 paths), endpoint-index.md, and the SPA (945 request literals + its test mocks, incl. regex/positional URL parsers) were regenerated/swept in lockstep. No wire-DTO or status-code change — only the path prefix moved.

Legacy compat = an in-pipeline rewrite, NOT a redirect (ApiVersionRewriteMiddleware, sequenced before UseRouting in the API branch). A legacy caller hitting an unversioned /api/foo has its request path rewritten to /api/v1/foo and continues in-pipeline — method, body, auth headers and query string all survive, so curl / the future MCP server / bookmarked URLs keep working with no round-trip (a 307/308 redirect would have been fragile for non-GET + custom-header clients). Rewritten (legacy) responses carry RFC 8594 Deprecation: true

• Link: </docs>; rel="deprecation", and a Sunset header when Api:LegacyRoutesSunset is configured. An already-versioned path (/api/v1/*) passes through untouched; a future /api/v2/* is not forced back to v1 (the middleware only fills in a missing version).

Freeze semantics (owner decisions): once shipped, /api/v1 is additive-only — new endpoints/optional fields are fine; renaming/removing/retyping an existing one requires a new /api/v2, never an in-place break. The legacy-rewrite compat shim has a 2-release sunset window (owner-chosen) before removal; the actual removal is a tracked Phase-3 follow-up, not this PR. Existing pre-freeze warts (e.g. channel {id} vs {channelNumber}, the synthesized negative-id "(none)" group rows) are frozen as-is per their own prior decisions.

Route-convention standardization (#286, owner-requested). The leading-slash inconsistency (238 absolute "/api/…" method routes vs 13 relative "api/…") is resolved: the standard is a leading-slash absolute route on each method's [Http*] attribute, no class-level [Route] — except the two controllers where many actions share a parametrized prefix (ScannerController {scanId}, ScriptedScheduleController {buildId}, ~40 methods), which keep a leading-slash absolute class [Route("/api/v1/…")] with relative method segments (the right tool for a shared prefix). Enforced by ApiRouteVersioningTests: it reflects over every [ApiController] in Controllers.Api, computes each action's effective route (ASP.NET's class+method combination rule), and asserts it matches ^/api/v\d+/ — so a new controller that drifts (relative or unversioned) fails CI, the "fix-it-while-you're-in-the-file" gate the dotnet format rules use. Browser-nav endpoints deliberately outside /api (e.g. GET /auth/oidc/login) are out of scope for the test. Docs: api-conventions.md §1/§9. Refs #286 #197.

2026-07-13 — Scheduling API hardening: null-name 500s, duplicate template items, unreachable 404 (#172)

key: api.scheduling-hardening · status: active · since: 2026-07-13 · supersedes: none · superseded-by: none Rule: Create/Replace handlers guard against null/whitespace name (IsNullOrWhiteSpace, not just Length) to prevent NRE-500s, template-item overlap validation compares by index (not record value-equality) to catch exact-duplicate items, and unreachable 404 ProducesResponseType attributes on create-only actions are trimmed. Signals: BlockTemplateItem record value-equality bypass, api-conventions.md §3b handler-hardening checklist · paths: ReplaceTemplateItemsHandler, api-conventions.md §3b · issues: #172, #144 Mechanics: docs/api-conventions.md §3b

Cleared the still-live findings from issue #172 (consolidated non-blocking nits from the #144 S1/S2 reviews). Most of the 2026-07-07 list had already been ratified deliberate (§8 "(none)" synthesized rows; §3b deep-FK non-existence-check) or fixed since (the unauthenticated /api/logs + /api/troubleshoot/info GETs now carry [RequiresAuthentication] per §9; the Trakt matched-items link points at the live /app/search; GET /api/search already fans out via Task.WhenAll). Three were genuinely live:

• Null/empty name → 500 (10 handlers). Create + Replace/Update handlers for Block, Template, DecoTemplate, Deco (8, all genuine 500s), plus UpdateFFmpegProfile (genuine 500; CreateFFmpegProfile was already guarded) and CreatePlaylist (its DTO coalesces null→"", so an empty-name persist, not a 500) all did if (request.Name.Length > 50) on a client-nullable string Name → unhandled NullReferenceException. Fixed to if (string.IsNullOrWhiteSpace(request.Name) || request.Name.Length > 50) — kills the NRE, and also rejects empty/whitespace names (matching the group-create handlers' NotEmpty behavior, closing a latent "block/template named ''" gap). Chose the one-line guard over refactoring each handler onto the NotEmpty/NotLongerThan combinator to keep the blast radius tiny and preserve each handler's existing error message + 422 mapping. Convention captured in api-conventions.md §3b handler-hardening checklist.
• Exact-duplicate template items bypassed overlap validation. ReplaceTemplateItemsHandler's O(n²) overlap loop skipped on item == otherItem, but BlockTemplateItem is a record, so two value-identical items (same BlockId + StartTime → same computed EndTime) were value-equal and skipped — both persisted unvalidated. Switched to index-based iteration (i != j) so identical items at distinct positions are compared and register as a (self-)intersection → rejected 422. (The SPA's index-based check already caught this client-side; it was an API-only gap.)
• Unreachable 404 on create-group actions. POST /api/blocks/groups and POST /api/templates/groups declared [ProducesResponseType(ProblemDetails, 404)] copied from precedent, but a create has no parent lookup that can 404 (only 201/422). Trimmed — OpenAPI spec regenerated.

Deliberately not fixed (documented as accepted): the §8 "(none)" synthetic rows, the §3b deep-FK non-existence-check, and the missing Name= on PlayoutController Create/Delete/Update (moot — the "v1"-doc OperationIdOpenApiTransformer (#197 Bundle C) already synthesizes stable operationIds for Name=-less ops, and adding Name= would risk renaming generated SPA client methods). Refs #172 #197.

2026-07-16 — Functional-E2E CI harness: advisory curl-contract job over an app booted from source (#299)

key: ci.functional-e2e-harness · status: active · since: 2026-07-16 · supersedes: none · superseded-by: none Rule: The functional-e2e CI job boots the PR's own code from source via dotnet run (scripts/e2e-local.sh) and runs curl-only, deterministic assertions (scripts/e2e-functional.sh) as an advisory (non-blocking) job, not a build dependency or required check. Signals: staged rollout precedent (migrations job), racy/interactive flows deferred · paths: scripts/e2e-local.sh, scripts/e2e-functional.sh · issues: #299 Mechanics: scripts/e2e-functional.sh

The manual live-E2E curl flows sessions had been re-running by hand (and leaving only as PR/issue comments) are now a CI regression net. Two decisions shaped it:

Boot from source + dotnet run, not the built image. The only "E2E" in CI before this was the smoke test in the build job, which runs against the pushed image — so it exists only on main/v* (the image isn't built on PRs) and would test a stale image, not the PR's code. To gate PRs on the PR's own code, the functional-e2e job builds the SPA + solution and launches dotnet ErsatzTV.dll via the same scripts/e2e-local.sh used locally (parameterized with ETV_BUILD_CONFIG=Release). The assertions live in scripts/e2e-functional.sh, so the identical harness runs by hand and in CI — which is the point of the issue (stop re-deriving the flows each session).

Advisory, not blocking — separate job, not a build dependency, not a required check. Per the issue's "a functional-E2E flake must not block the unit-test gate." A boot-the-app job has more moving parts (background process, port, readiness wait) than a pure unit test, so it starts advisory and gets promoted to a required check / build dependency once proven reliable — the same staged rollout the migrations job used. SQLite is the default provider, so it needs no DB service container.

Scope is curl-only and deterministic; the racy/interactive flows are explicitly deferred. The first cut asserts the legacy→SPA redirect sweep (+ /api//artwork never-redirect exemption), the auth/CSRF/security-stamp flow, the library-scan status contract (404/202/scan-status), and the If-Match/412 round-trip — all exercisable without seeded media, ffmpeg-transcode, or a browser (an empty local library still enqueues 202; an empty collection drives the concurrency editor). The 409 "already-scanning" re-trigger (needs a long-running scan to be non-racy), the playout-build lock 409, and the genuinely UI-interactive Playwright flows are deferred as #299 follow-ups rather than shipped flaky. Assertions were written against a real running instance, not the source — which caught that /artwork/* returns 400 (not the 404 a static read suggested); extend the harness the same way.

2026-07-16 — Optional advertised IPTV base URL (iptv.base_url) resolved centrally in the two generators (#340)

key: iptv.base-url · status: active · since: 2026-07-16 · supersedes: none · superseded-by: none Rule: An optional advertised base URL (iptv.base_url) is resolved centrally via a pure Core helper (AdvertisedBaseUrl) inside the two IPTV generation handlers (M3U + XMLTV); unset/malformed values fall back byte-identical to the request-derived host, and it's a new iptv settings group distinct from ETV_BASE_URL and out of scope for HDHomeRun. Signals: AdvertisedBaseUrl.TryParse/Resolve, ConfigElementKey.IptvBaseUrl, request-derived-host symptom (Gitea #1) · paths: ErsatzTV.Core/Iptv/AdvertisedBaseUrl.cs, docs/m3u-xmltv.md · issues: #340 Mechanics: ErsatzTV.Core/Iptv/AdvertisedBaseUrl.cs, GET/PUT /api/v1/settings/iptv

ErsatzTV's absolute IPTV URLs (M3U stream/logo/guide URLs, XMLTV <icon>/artwork) were always derived from the incoming request's Scheme/Host/PathBase, so any client that fetched with a host downstream consumers can't resolve (the historical Gitea #1 localhost:8409 symptom) baked that host into the output. #340 adds an optional advertised base URL to pin those URLs to a fixed public origin. Several deliberate decisions shaped it:

(a) Resolve the override centrally in the two generation handlers, via a pure Core helper — not in the controller. A new ErsatzTV.Core/Iptv/AdvertisedBaseUrl.cs exposes TryParse(string) → Option<(scheme, host, baseUrl)> and Resolve(configured, requestScheme, requestHost, requestBaseUrl). GetChannelPlaylistHandler (M3U, via ChannelPlaylist) and GetChannelGuideHandler (both XMLTV {RequestBase} substitution sites) call Resolve and use its result instead of the raw request values. Keeping the logic in a pure, allocation-free Core helper (not the thin controller) keeps controllers dumb, makes the parse/validate/resolve rules unit-testable in isolation, and — because the fallback path returns the exact request-derived values — leaves the M3U/XMLTV golden tests (ChannelPlaylistGoldenTests, ChannelGuideGoldenTests) untouched.

(b) Validation rules, with blank/invalid → request-derived so "unset" is byte-identical. TryParse accepts only an absolute http(s) URL with no credentials, query, or fragment; it preserves the port and any path prefix and normalizes a trailing slash off. Anything failing these rules → None, and Resolve then falls back to the request-derived scheme/host/base. So an unset or malformed value produces output byte-for-byte identical to today's request-derived behaviour — the override is strictly opt-in and can never silently corrupt the default path.

(c) A NEW iptv settings group, not folded under xmltv. The base URL affects both the M3U playlist and the XMLTV guide, so it does not belong under the existing XMLTV-only settings. GET/PUT /api/v1/settings/iptv on SettingsController (tier [RequiresAuthentication]) with body { baseUrl }, backed by GetIptvSettings/UpdateIptvSettings handlers + IptvSettingsViewModel / IptvSettingsResponseModel / UpdateIptvSettingsRequest, and a new "IPTV" section on the SPA Settings screen. Follows the existing settings GET/PUT pattern — no new API convention.

(d) Blank clears the key; non-blank malformed → 422. A blank/whitespace baseUrl on PUT deletes the ConfigElement (reverting to request-derived); a non-blank value that fails AdvertisedBaseUrl.TryParse is rejected with 422 rather than being silently stored and ignored at generation time — the error surfaces at the point of configuration.

(e) Scoped to M3U + XMLTV, deliberately NOT HDHomeRun. #340 covers only the M3U playlist and XMLTV guide generators. The HDHomeRun lineup URLs still echo the request host; extending the override there was explicitly out of scope.

(f) Distinct from ETV_BASE_URL. The ETV_BASE_URL environment variable only sets the ASP.NET Core PathBase (request routing/prefix); it does not advertise a scheme+host. iptv.base_url is the separate, DB-stored (ConfigElementKey.IptvBaseUrl, no EF migration) advertised origin for IPTV output. See docs/m3u-xmltv.md → "IPTV base URL (#340)".

2026-07-16 — Auto-tuning enumerates via EF, persists via SmartCollection; additive coexistence (#69)

key: sched.auto-tune-foundation · status: active · since: 2026-07-16 · supersedes: none · superseded-by: none Rule: Auto-tune preview enumeration uses EF distinct+count queries for exact counts, while each created channel is persisted as a live SmartCollection; coexistence with existing channels/numbers is additive-only, never mutating. Signals: auto-tuning, SmartCollection, additive coexistence, channel numbering · paths: CreateChannelFromLineup · issues: #69, #63 Mechanics: PreviewAutoTuneChannelsHandler, AutoTuneAxisMap, ISender-based CreateChannelFromLineup primitive

Auto-tuning (#69) generates channels from library metadata (TV Show / TV Genre / Movie Genre). Enumeration for the preview uses EF distinct+count queries (exact counts drive the min-items threshold and preview display); each created channel is backed by a newly-created SmartCollection (live Lucene query) so channels keep tracking the library as it grows. Query authorship is server-side only — the client passes {axis, value}, never a Lucene string. Coexistence is additive: the batch gets a reserved starting channel number (skipping taken numbers), a proposed channel whose name already exists is flagged and de-selected by default, and existing channels are never mutated. Bulk create loops the #63 CreateChannelFromLineup primitive via ISender and returns a per-channel Created/Skipped/Failed outcome. Known MVP limitation: the generated SmartCollection is named after the channel; a name collision with an existing SmartCollection surfaces as a per-channel Failed outcome.

2026-07-16 — Per-playout reshuffle = scoped Reset build; seed surfaced (#71)

key: sched.reshuffle-scoped-reset · status: active · since: 2026-07-16 · supersedes: none · superseded-by: none Rule: POST /api/v1/playouts/{id}/reshuffle runs ErasePlayoutHistory (reseeds Playout.Seed + clears anchors/rerun-history) then enqueues a scoped Reset build, so reshuffle always reseeds — even for the non-Classic kinds Reset alone wouldn't reseed; Playout.Seed is surfaced on list/detail DTOs as visible confirmation. Signals: reshuffle, Playout.Seed, ErasePlayoutHistory, CollectionEnumeratorState · paths: PlayoutBuilder · issues: #71 Mechanics: POST /api/v1/playouts/{id}/reshuffle; ErasePlayoutHistory; PlayoutBuildMode.Reset

• The shuffle seed (Playout.Seed) + per-collection CollectionEnumeratorState already persist a stable shuffled order across rebuilds. #71's real gap was a user-triggered per-playout reshuffle (a Classic playout's seed is otherwise only reseeded by a full Reset, and reset-all uses Refresh for Classic, so it never reseeds Classic) plus visibility.
• POST /api/v1/playouts/{id}/reshuffle first runs ErasePlayoutHistory (reseeds Playout.Seed + clears anchors/rerun-history) and then enqueues BuildPlayout(id, PlayoutBuildMode.Reset) to rebuild. Reset alone only reseeds the seed for Classic playouts (PlayoutBuilder); Block/Sequential/Scripted rebuild deterministically from the existing seed, so ErasePlayoutHistory is the one primitive that reseeds + clears the derived per-collection enumerator state for all four resettable kinds — reshuffle runs it first so the reshuffle is never a no-op for non-Classic playouts. Named /reshuffle (not /reset) to (a) match user intent and (b) avoid the "reset-one reseeds Classic while reset-all refreshes Classic" naming clash. It is deliberately more aggressive than reset-all for Classic: an explicit single-channel action rolls a new order; the bulk action stays non-disruptive.
• Playout.Seed is surfaced on the playout list + detail DTOs so the SPA can show it — its purpose is visible confirmation (the seed changes after a reshuffle).

2026-07-17 — Clock-boundary schedule padding already exists (FillerMode.Pad); #77 verified, convenience toggle deferred

key: sched.clock-padding-existing · status: active · since: 2026-07-17 · supersedes: none · superseded-by: none Rule: Clock-boundary padding already exists via FillerPreset's FillerMode.Pad (Classic) and pad_to_next/pad_until (Sequential/YAML); #77 is closed as verified+documented, not built new, with a one-click per-channel toggle deferred behind the #388 design-system epic. Signals: clock padding, FillerMode.Pad, pad_to_next, EPG guide-stop coalescing · paths: PlayoutModeSchedulerBase.AddFiller, ChannelGuideProjector.ProjectFlood, /app/filler-presets · issues: #77, #388 Mechanics: PlayoutBuildGoldenTests.Classic_clock_padded, ChannelGuideProjectorClockPadTests

#77 asked to "pad/snap channel schedules to clock boundaries (:00/:15/:30) using filler" — a Tunarr "Pad Times" analogue for broadcast-looking guides. Investigation found the core is already implemented (upstream ErsatzTV machinery carried into the fork), so #77 was scoped to verification + documentation rather than a new feature:

• Classic playouts: a FillerPreset with FillerMode.Pad + PadToNearestMinute = N snaps each content item up to the next N-minute clock mark, filling the gap with the preset's filler collection (falling back to the item/channel fallback filler). The boundary math is a ceiling-to-the-next-multiple on the local minute with seconds zeroed (PlayoutModeSchedulerBase.AddFiller, the FillerMode.Pad block). Live SPA editor at /app/filler-presets (increment options 5/10/15/30).
• Sequential (YAML) playouts: the pad_to_next: N and pad_until: "HH:mm" instructions do the same, reusing the identical boundary formula.
• Block playouts: no per-item Pad, and none is needed — Block is inherently clock-anchored (each Block starts at a fixed TemplateItem.StartTime), so it already yields clean guide times.
• EPG reflects the padding with no extra code: ChannelGuideProjector.ProjectFlood coalesces trailing PostRoll/Tail/GuideMode/Fallback/DecoDefault filler into the programme window, so a programme's Stop is the padded boundary (the filler run's finish), not the raw content finish.

What this decision fixes in the record: the issue's premise ("reverses an earlier not-adopting call") predates the machinery; do not re-implement pad-to-boundary from scratch. Two deterministic tests lock the behaviour end-to-end (chosen over a one-off live-E2E because #77 changed no production code, so the live-E2E's write-path/500 justification does not apply): PlayoutBuildGoldenTests.Classic_clock_padded (schedule → PlayoutItems land on :15 through the real PlayoutBuilder) and ChannelGuideProjectorClockPadTests (those items → guide programmes stop on :15).

Deferred (UI-gated): the only real residual is convenience — there is no one-click per-channel / per-schedule "clock-align this whole channel" toggle; today you hand-build a Pad FillerPreset and wire it into a schedule item's roll slot. That toggle is mostly SPA work and is deferred to a follow-up blocked on the #388 design-system sync epic (all UI work is currently gated on #388), which also covers adding a 60-minute increment to the filler-preset editor's options (the backend already accepts any integer).

2026-07-17 — Shuffle-source construction extracted to ShuffleSourceBuilder; per-family seam, not a god-factory (#380)

key: sched.shuffle-source-builder · status: active · since: 2026-07-17 · supersedes: none · superseded-by: none Rule: Shuffle-source construction moves to a static, DI-free ShuffleSourceBuilder (a shared seam, not a service) so Classic and Playlist stop cross-engine reaching into PlayoutBuilder statics; a unified Classic+Playlist enumerator factory is explicitly rejected as a god-factory. Block/Scripted/YAML duplication is left alone, deferred to a follow-up gated on #381. Signals: ShuffleSourceBuilder, PlaybackOrder, cross-engine reach-in, god-factory rejection · paths: ErsatzTV.Core/Scheduling/ShuffleSourceBuilder.cs, PlayoutBuilder, PlaylistEnumerator · issues: #380, #163, #176, #70, #381 Mechanics: ShuffleSourceBuilder.GetGroupedMediaItemsForShuffle/GetCollectionItemsForShuffleInOrder; classic-shuffle golden in PlayoutBuildGoldenTests

PlaybackOrder is turned into an enumerator at five independent sites (one per schedule kind, dispatched by BuildPlayoutHandler on ScheduleKind): Classic (PlayoutBuilder), Block (BlockPlayoutBuilder, PlayoutHistory rotation), Scripted (SchedulingEngine.EnumeratorForContent), Sequential/YAML (EnumeratorCache), and the Playlist leaf (PlaylistEnumerator.Create, consumed by the others). These are not accidental duplication — they map the same enum to different enumerator families keyed on different state models (Block's history cursor vs the stateless-index CollectionEnumeratorState enumerators). The real smell was one cross-engine reach-in: PlaylistEnumerator called PlayoutBuilder.GetGroupedMediaItemsForShuffle / GetCollectionItemsForShuffleInOrder as statics — one engine reaching into another engine's class.

• Fix (a) shipped, not (b). The two shuffle-source helpers moved verbatim to a new public static class ShuffleSourceBuilder in ErsatzTV.Core/Scheduling (sibling to the also-static MultiCollectionGrouper / MultiPartEpisodeGrouper; dependencies passed as parameters, not a DI service — PlaylistEnumerator.Create is itself a static factory). Both Classic and Playlist now consume it, so the reach-in is gone and shuffle-source construction lives in one directly-unit-tested place.
• One intentional signature change. GetGroupedMediaItemsForShuffle now takes bool keepMultiPartEpisodesTogether, bool treatCollectionsAsShows instead of a ProgramSchedule (verified those are the only two properties it read). This deletes PlaylistEnumerator's fake new ProgramSchedule { KeepMultiPartEpisodesTogether = false } (its TODO becomes an honest false, false) and gives future callers with no ProgramSchedule (#176 PseudoTV, #70 distribution) a schedule-entity-free entry point. Behavior is unchanged.
• Rejected: a unified Classic+Playlist enumerator factory (b). That would be the god-factory the issue forbids — three concrete hazards: Classic's Marathon arm produces a PlaylistEnumerator (a factory consumed by PlaylistEnumerator.Create that also builds one is a dependency cycle); Playlist hardcodes KeepMultiPartEpisodesTogether=false/randomStartPoint=false where Classic reads schedule flags (a merge silently changes behavior); and Classic's CustomOrder/Rerun/MultiEpisodeShuffle-template arms gate on instance deps Playlist doesn't have. Engine separation is deliberately preserved.
• Block / Scripted / YAML left alone. Block is a distinct family; the Scripted≡YAML construction duplication (EnumeratorForContent ≡ EnumeratorCache.GetEnumerator, both using the different BlockPlayoutShuffledMediaCollectionEnumerator for shuffle) is a real but separate cleanup — deferred to a follow-up gated on #381 (those paths have no golden coverage yet).
• Net first, because #163's was too narrow. PlayoutBuildGoldenTests only pinned PlaybackOrder.Chronological; the moved shuffle paths (incl. the entire Playlist reach-in) were uncovered, so "goldens green" would have been a false signal. The PR adds a classic-shuffle golden (pinned Playout.Seed + Continue build, since Reset randomizes the seed) and a PlaylistEnumerator.Create reach-in characterization (Shuffle + ShuffleInOrder items) before the move, plus direct ShuffleSourceBuilder unit tests for the branches goldens don't reach (multi-collection vs fake-multi-collection lookup; multi-part grouping on/off).

2026-07-17 — Seasonal / date-conditional scheduling already exists (alternate schedules / playout templates); #73 closed as implemented

key: sched.seasonal-scheduling-existing · status: active · since: 2026-07-17 · supersedes: none · superseded-by: none Rule: Seasonal/date-conditional scheduling already ships first-class via IAlternateScheduleItem (Classic ProgramScheduleAlternate, Block PlayoutTemplate) evaluated by AlternateScheduleSelector.GetScheduleForDate (first match in Index order, catch-all last); #73 is closed as already-implemented with a docs-only "seasonal/holiday" recipe added, not new code. Signals: alternate schedules, playout templates, date-conditional, catch-all-last evaluation · paths: AlternateScheduleSelector.cs, PlayoutBuilder, EffectiveBlock, DecoSelector, PlayoutScheduleEditors.tsx · issues: #73, #70 Mechanics: AlternateScheduleSelectorTests, playoutTemplateCalendar.test.ts; channels.md "Recipe: seasonal / holiday programming"

#73 asked for "seasonal / date-conditional channels & schedule rules" — a PseudoTV holiday-channel analogue — on the stated premise that "ErsatzTV has no native date-conditional scheduling today; you'd hand-build it seasonally." That premise is false. The feature is first-class, shipped, SPA-reachable, unit-tested and already documented (upstream machinery carried into the fork). #73 is closed as already-implemented; the only deliverable was the docs recipe below.

• The predicate: IAlternateScheduleItem (DaysOfWeek, DaysOfMonth, MonthsOfYear, LimitToDateRange, StartMonth/StartDay/StartYear?, EndMonth/EndDay/EndYear?), implemented by ProgramScheduleAlternate (Classic — picks the ProgramSchedule for a date) and Scheduling/PlayoutTemplate (Block — picks the Template + optional DecoTemplate for a date).
• The evaluator: AlternateScheduleSelector.GetScheduleForDate — first match in Index order, broadest/unconditional row last = catch-all. Wired into PlayoutBuilder (:572, :956), EffectiveBlock, BlockPlayoutFillerBuilder, and DecoSelector. Wrap-around (Nov→Feb) and invalid/leap dates (Feb 31 clamped) are already handled; AlternateScheduleSelectorTests + playoutTemplateCalendar.test.ts pin it.
• SPA: PlayoutScheduleEditors.tsx ships the "Limit to date range" control for both editors, with a per-date calendar preview (playoutTemplateCalendar.ts).
• Nullable years are the seasonal switch (AlternateScheduleSelector.cs:32-40): years default to the queried date's year, so blank years = repeats every year. The override branch requires both StartYear and EndYear (only one → silently still yearly), and explicit years force reverse = false, disabling wrap-around. This was the single most load-bearing undocumented behaviour and is now in the docs.
• Correcting the issue's Deco hypothesis: the issue proposed "a Deco-like modifier". Decos carry no dates — DecoTemplateItem.StartTime/EndTime are time-of-day. The date dimension lives exclusively on the PlayoutTemplate / ProgramScheduleAlternate join row. Composition is PlayoutTemplate (date range) → Template (time-of-day grid) → Block (content).

Why closed rather than #77-style "re-scope to verify + document": #77 had two real gaps (undocumented AND untested). #73 has neither — tests and docs both already existed on main — so even the #77 re-scope target was already met. Under the close-don't-park convention (same date), holding #73 open for a hypothetical future build is precisely the parking that convention forbids.

Rejected asks, and why:

• Per-schedule-item date predicate (the issue's literal ask; shipped design swaps the whole schedule per date instead). Rejected as-designed: functionally equivalent for every seasonal use case — clone a schedule, date-gate it, order it above the catch-all — at a cost of "clone a schedule". Moving the predicate onto ProgramScheduleItem rows would touch the classic playout builder's core loop for zero new expressible behaviour, carrying regression risk in the exact engine #163/#380 just built golden nets around.
• "Prioritize collection X during a date range" — routed to #70, not built here. The ask decomposes as date scoping (shipped) × soft prioritization (the weighting primitive #70 is actively building across the PlaybackOrder switch sites). Once #70 lands, this is pure composition with no date-aware code in the weighting path. Building a second weighting primitive under #73 while #70 was mid-flight would have been a direct collision in the same milestone.
• Date-gating a playout's default Playout.DecoId — rejected: the gated path already exists (PlayoutTemplate.DecoTemplateId), and a date-conditional fallback is a contradiction in terms.
• UI rename of "Alternate Schedules" / "Playout Templates" to something that reads as "seasonal" — rejected: inherited upstream vocabulary baked into routes, API paths and parity docs; churn for marginal gain. The discoverability gap is addressed with docs instead.

Known non-goal: the issue's "optionally, auto-surface a seasonal channel in the lineup during its window" is genuinely absent — M3U/XMLTV lineup visibility is not date-conditional. It was speculative, has no concrete use case (the practical equivalent: air a date-gated schedule year-round, or toggle ShowInEpg), and per close-don't-park no placeholder issue was filed. Refile if a real need appears.

The real gap was discoverability, and it was a docs gap. The mechanism was documented as a mechanism ("Alternate Schedules… useful for seasonal programming") but never as a task — a user thinking "holiday channel" has no reason to look under "Alternate Schedules", and on finding that line gets no worked steps. Fixed with a task-shaped "Recipe: seasonal / holiday programming" section in channels.md (both engines, plus the gotchas above) and a domain-model.md glossary row. No production code changed, so no live-E2E (same reasoning as #77).

2026-07-17 — Auto-Tune DetailPanel member list = live search-index roll-up, not EF enumeration (#384)

key: sched.autotune-detailpanel-members · status: active · since: 2026-07-17 · supersedes: none · superseded-by: none Rule: The Auto-Tune DetailPanel's per-channel content-source list is a live ISearchIndex.Search roll-up through the server-owned AutoTuneAxisMap.GenerateQuery, not an EF distinct+count query, so the preview matches exactly what the built channel's SmartCollection will contain. Signals: Auto-Tune DetailPanel, search-index roll-up, SmartCollection fidelity · paths: GET /api/v1/channels/auto-tune/members, MediaCollectionRepository.GetSmartCollectionItems · issues: #384, #383, #69, #385, #386 Mechanics: AutoTuneAxisMap.GenerateQuery; LibraryBrowseItemMapper.GetShows/GetMovies; PagedLibraryBrowseItemsResponseModel

The Auto-Tune DetailPanel (#383) shows, per proposed channel, the distinct content sources its generated SmartCollection resolves to (a genre channel's shows/movies), each weightable in the #385 write path. GET /api/v1/channels/auto-tune/members?axis=&value= backs that list.

Why the search index, not an EF distinct+count query — even though #69's preview enumeration uses EF (PreviewAutoTuneChannelsHandler.EnumerateTvShows/…). The created channel's playout is built from a SmartCollection whose members come from ISearchIndex.Search (MediaCollectionRepository.GetSmartCollectionItems). For the DetailPanel to faithfully preview what the built channel will actually contain, the member list must run the same query through the same index — so the handler calls the server-owned AutoTuneAxisMap.GenerateQuery(axis, value) (client never sends Lucene, per #69 PR1) and rolls the matching leaf items up to their distinct parents. #69's preview is a different granularity (enumerating candidate axis values with EF exact counts to drive the min-items threshold); this is enumerating the members of one value, where index-fidelity matters more than count-exactness. The two coexist deliberately.

Roll-up + shape. Episode axes (TvShow/TvGenre) → distinct parent shows (Episode→Season→ShowId), with ItemCount = the query-matching episode count, not the show's total (a show contributes only its matching episodes to a genre channel). Movie-genre axis → the matching movies are themselves the sources. Both reuse the existing PagedLibraryBrowseItemsResponseModel / LibraryBrowseItemResponseModel DTOs and LibraryBrowseItemMapper.GetShows/GetMovies (no new schema), ordered by title then id, paged in memory (the distinct-source set is bounded — dozens for a genre). Search pulls up to the 10k cap GetSmartCollectionItems already uses; a value resolving to >10k leaf items could under-report sources past the cap — the same staleness bound the smart-collection path accepts. Read-only, catalog-read tier (no [RequiresAuthentication]), so a cold review sufficed. Sibling backend child #385 (write-path overrides + weights) and SPA child #386 remain open under the #383 milestone.

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2026-07-17 — No persistent compiler servers in CI; every services: container gets an explicit cap; #390's small-lane move reversed (#406)

key: ci.runner-placement · status: active · since: 2026-07-17 · supersedes: none · superseded-by: none Rule: No persistent Roslyn compiler server survives a CI build (UseSharedCompilation=false etc., runner env + Dockerfile ENV); every services: container gets its own explicit --memory/--memory-swap/--cpus cap (it does not inherit the job container's). Signals: CI memory/swap thrash · paths: .gitea/workflows/*.yml, docker/Dockerfile · issues: #406, #390 (prose-reversed, no standalone record), server-management#604, server-management#570 Mechanics: docs/ci-cd.md → CI build memory; scripts/ci-peak-anon.sh

Three CI changes, all downstream of one incident: on 2026-07-17 bumblebee (the prod media Docker host, 25 GiB / 12 cores) hit load 340 with 21 GiB swapped and ~238 MiB free, taking prod ersatztv/jellyfin down until reboot. Prod ersatztv itself was healthy at 168 MiB throughout — the thrash was CI-induced, triggered by a burst of parallel merges to main. Infra sizing is server-management#604's boundary; these three levers live in this repo and each does more than any capacity knob.

1. No persistent compiler servers. VBCSCompiler is a persistent Roslyn server: it outlives the dotnet build that started it and holds its heap for the next one. Measured at 7.8 GB RSS live on bumblebee — the single largest consumer on the box, and the actual reason each job needed a 10 GiB cap. In CI it buys nothing: each job container is torn down at the end of the run, so there is never a "next build" to warm. The workflow's top-level env: now sets UseSharedCompilation=false, DOTNET_CLI_USE_MSBUILD_SERVER=0, MSBUILDDISABLENODEREUSE=1 — MSBuild properties set as env vars so they apply to every dotnet call without touching each call site (MSBuild surfaces env vars as properties; UseSharedCompilation only defaults to true when empty, so the env var wins). Verified locally: a default build leaves 1 VBCSCompiler alive, the same build under these vars leaves 0, and ErsatzTV.sln still builds clean (0 errors).

Why the Dockerfile also sets them — and this is the part the issue's suggestion would have missed: the workflow env: reaches the runner-side dotnet jobs only. The build job compiles inside docker build, where it does not propagate, so the SDK stage of docker/Dockerfile sets the same three as ENV. That is precisely the job server-management#570 measured pegging 5.999/6 GiB — the one that most needs it. Build-stage only; the final image is FROM runtime-base, so nothing lands in the shipped image or affects runtime.

Trade-off accepted: without the shared server each project's csc is a fresh process, which costs some build time. Worth it — the memory spike is what takes prod down, and the cap sizing that spike forces is what starves the lanes.

2. services: containers do not inherit the runner's cap. A runner's container.options (--cpus=4 --memory=10g) applies to the job container only. Verified by inspecting a live migrations job: the job container reported HostConfig.Memory=10737418240, its mysql:8.4 service reported mem=0 nanocpus=0 — unbounded. Every migrations run was adding an uncapped MySQL to an already-tight host. Now --memory=2g --memory-swap=2g --cpus=2.

Why --memory-swap is not redundant (cold-review catch, and the sharpest thing in this change): Docker defaults an unset --memory-swap to twice --memory, so --memory=2g alone grants 2g RAM plus 2g of swap — verified live: --memory=2g → memory.max=2147483648 and memory.swap.max=2147483648; --memory=2g --memory-swap=2g → memory.swap.max=0. Capping RAM while silently permitting swap is close to the worst outcome on the host whose swap thrash is the entire reason for the cap, and a swapping mysqld mid-DDL is exactly the pathology behind the known Command Timeout expired migrations flake — i.e. the naive cap could have made that flake worse. Standing rule: prefer a loud OOM over silent swapping. An OOM is an unambiguous "raise the cap" signal; swapping just degrades everything and blames something else.

The same 2× applies to the runners' 10g job slots — each is really 10 GiB RAM plus 10 GiB swap, so the "60 GiB promise on a 25 GiB host" understates by 2× and is a plausible direct mechanism for the incident's 21 GiB swapped. That is server-management#604's boundary; reported there.

On 2g, honestly: 543 MiB is init+idle, not the 787-migration replay (which grows caches idle never touches), so 2g is a measured floor plus headroom, not a measured ceiling — the migrations job going green is what validates it. --cpus=2 has no measurement behind it at all; 787 sequential DDL statements on one connection are ~1-core-bound, so it is judgement. Recording that rather than dressing a guess as measurement — the same failure this entry criticises below.

Standing rule: any new services: container needs its own explicit cap — it will not inherit one, and --memory without --memory-swap silently grants 2× in swap.

3. #390's small-lane move for api-docs/format reversed. #390 moved them to dodge a ~29 min ubuntu-latest queue. The queue was real, but the lane was the wrong fix, and #390's own comment flagged why: "on an API-touching PR this job does a full dotnet build, so it is not always a 'small' job; capacity 4 absorbs that." "Capacity 4 absorbs that" held only because nothing enforces the sum of the lanes' caps — 6 slots × 10 GiB on a 25 GiB host is a 60 GiB promise. These are not small jobs: a live docker stats caught the format job container at 3.95 GiB, which #604's re-sized 2 GiB small lane would OOM-kill outright. #604 grows ubuntu-latest to 5 slots (48 GiB ci-runner at capacity 4 + a bumblebee overflow slot) and fixes the queue at the source. This one is order-coupled with #604: the small lane's caps can't tighten until it lands.

Measurement is now continuous, not a one-off. The test job's last step reports the cgroup's memory.peak plus an anon/file breakdown (continue-on-error, tolerates absence). #604 sizes both runners' caps on that number, and until now it was inherited rather than measured — the 10g cap traces back to #570 observing a different job entirely. Two things that look like details but are the whole point: it must run last (memory.peak read at step N reports the peak only up to N, so an earlier placement silently excludes the job's later workload), and continue-on-error — not if: always() — is what makes it advisory (always() controls whether a step runs, not whether its failure fails the job, and defaults.run.shell: bash means -e is on).

And then the instrument taught us the lesson twice, both times at our own expense. The first reading came back peak 8305 MiB. memory.peak is the high-water mark of memory.current, which charges page cache as well as anonymous memory — proven: a container with anon=0 that merely reads an 800 MB file reports memory.peak=826 MiB, file=800 MiB. Page cache is reclaimed under a tighter cap, not OOM-killed, so a large peak that is mostly file is not evidence a cap must stay high. anon is what forces an OOM; size caps on it. The step now prints the split (end-of-job, so indicative rather than peak-instant); a true peak-anon sample is #412.

Then we made the same mistake in the opposite direction. Having established that peak overstates, the docs (and a report to #604) leaned to "so this number is probably mostly cache." That was a guess about magnitude dressed in a verified fact about mechanism — and an independent probe killed it: a full solution build in the CI image with shared compilation off measured peak 9457 MiB / anon 7134 MiB / file 421 MiB. Anon dominated. So a 6g cap looks unsafe, #570's "6g proved too tight" is the rule rather than an outlier, and #406's premise ("if this brings peak RSS well under 6 GiB, the whole budget loosens") is looking dead — the 7134 MiB was measured with shared compilation already off. The switches are still right (no persistent 7.8 GB server between builds); the looser budget they were supposed to buy is not.

What is NOT established: there is still no pre-change baseline from this instrument — the 7.8 GB VBCSCompiler figure was measured host-wide across concurrent jobs, not inside one job container — and the anon figure above is one probe, not the test job. #412 covers the real A/B. What is established: no persistent compiler server survives a build, and migrations is green with mysql capped at 2g with swap disabled.

The lesson generalizes, and note it bit this change twice — once in the issue's premise and once in our own instrument: this repo's CI perf work keeps stating numbers from plausibility rather than measurement (see #390's "2–4min" apt-ffmpeg estimate; real 110s, and not load-bearing). Measuring the wrong quantity precisely is the same failure wearing a lab coat.

What this does NOT shrink: format. dotnet format loads Roslyn in-process via MSBuildWorkspace and never spawns csc, so its measured 3.95 GiB is untouched by any of this. Do not size the small lane expecting otherwise.

Not addressed here: the 12–35 min queue waits (server-management#604) and the redundant triple-build (#398).

2026-07-17 — Channel health on the API = the raw PlayoutCount fact on the list DTO, not a derived status enum (#72)

key: api.channel-health-signal · status: active · since: 2026-07-17 · supersedes: none · superseded-by: none Rule: Channel health rides ChannelResponseModel/ChannelListItem DTOs as a raw int PlayoutCount fact (free — GetAll already Includes Playouts), not a new endpoint, not /channels/state (runtime-liveness cadence), and not a derived ChannelHealth enum (would freeze policy before the #383/#384 auto-tune status taxonomy lands). Signals: channel health, PlayoutCount, config-derived vs runtime-liveness cadence, frozen /api/v1 · paths: ChannelRepository.GetChannel, Mapper.GetPlayoutsCount, api-conventions.md §3a · issues: #72, #383, #384, #401 Mechanics: api-conventions.md §3a (precedent: IsLocked on PlayoutListItemResponseModel); ChannelResponseModel.PlayoutCount

#72 asks for per-channel status in the Channels list, "especially channels that will fail to play".

Where it lives: ChannelResponseModel (the lean list DTO), not a new endpoint and not /channels/state. Channel health is config-derived — it changes when someone edits a playout, not tick to tick — whereas /channels/state is the fast-poll runtime-liveness feed (OnAir = someone is streaming right now). Folding health into the polled feed would recompute rarely-changing data every tick and mix two cadences in one DTO; a third endpoint is over-engineering for one derived integer on a list whose consumer already reads it. Precedent: api-conventions.md §3a stamps the server-derived IsLocked onto PlayoutListItemResponseModel for exactly this reason. It is also free: GetAll already Includes Playouts and MirrorSourceChannel.Playouts and was discarding them, so no extra query and no N+1 on a large lineup.

A raw fact (int PlayoutCount), not a ChannelHealth enum. v1 has exactly one trustworthy negative signal, and the auto-tune arc (#383/#384) is about to churn the status taxonomy (origin, auto-tune outcomes) — freezing a server-side enum now guarantees a breaking rev of a frozen-additive /api/v1 surface. PlayoutCount mirrors the long-standing ChannelViewModel.PlayoutCount 1:1, is a fact rather than a policy, and leaves the SPA to derive 0 ⇒ "No playout" in one predicate.

What v1 deliberately does NOT compute — each was considered and ruled out, so don't "finish" them without reading this:

• Empty schedule behind an existing playout. EmptyScheduleHealthCheck only understands Classic ProgramSchedule playouts. Block, Sequential, Scripted and ExternalJson channels have no ProgramSchedule at all, so a badge driven off that query would be silently absent or wrong for four of the five schedule kinds — the #71 "verify a shared primitive covers ALL variants" trap. Needs a per-kind emptiness notion first.
• Broken / missing source. FileNotFound/Unavailable are server-wide media-item counts with no channel attribution; mapping media → collection → schedule → channel is a project, not a field.
• User-defined vs auto-generated origin (#72 scope item a). No honest signal exists: Channel has no origin column, and ChannelPlayoutSource.Generated is a playout-strategy value that SPA-created blank channels also carry, so it would mislabel them. Requires a new column + a dual-provider migration, and provenance belongs to the auto-tune arc that stamps it at creation. A join through the "Channel Lineups" system playlist group was rejected: it is a heuristic that breaks the moment a user edits the channel. Deferred to a follow-up blocked on the auto-tune backend.

Keeping all three out held #72 to a read-path-only change: no migration, no write-handler live-E2E.

Corrected in passing: ChannelRepository.GetChannel never included Playouts, so GET /api/v1/channels/{id} reported playoutCount: 0 for every channel, which silently disabled the channel editor's playout-source guard. Both call sites now share Mapper.GetPlayoutsCount (Mirror-aware). The related silent server-side coercion of Mirror→Generated (a 200 that discards the caller's intent, against the §3 "surface it, don't silently filter" rule) is filed as #401, not fixed here.

2026-07-17 — Weighted / fair-share distribution is a new WeightedShuffle order; ShuffleInOrder is anti-clumping, not fair-share (#70)

key: sched.weighted-shuffle · status: active · since: 2026-07-17 · supersedes: none · superseded-by: none Rule: Fair-share/weighted airtime distribution ships as one new PlaybackOrder.WeightedShuffle = 9 order (equal weights = fair-share), not a retrofit of ShuffleInOrder (which only anti-clumps, since its padding spacers emit nothing) and not a separate orthogonal "distribution" setting; weights live on MultiCollectionItem/MultiCollectionSmartItem (DB default 1, dual-provider migration), bounded at write (1..1000) and clamped again in the enumerator, and the write path rejects WeightedShuffle at every dispatch site that doesn't handle it rather than let it silently degrade to unweighted random. Signals: WeightedShuffle, fair-share, ShuffleInOrder anti-clumping, MultiCollectionItem.Weight, write-path validation · paths: WeightedShuffleCollectionEnumerator, MultiCollectionGrouper, ShuffleSourceBuilder.GetCollectionItemsForShuffleInOrder, AddMultiCollectionItemWeight migration · issues: #70, #380, #403, #385, #386 Mechanics: CollectionWithItems.Weight; ReplacePlaylistItems/CreateChannelFromLineup write-path gates; EffectiveWeight clamp

PlaybackOrder.WeightedShuffle = 9 ships the two behaviors #70 asked for — "air Show A 70% / Show B 30%" and "no single show dominates" — as one order, because fair-share is the equal-weights case of weighted.

• ShuffleInOrder does NOT already do fair-share, despite looking like it. Its balanced shuffle (keyj) pads every source to the longest with Option<MediaItem>.None spacers — but spacers emit nothing (ShuffleInOrderCollectionEnumerator.cs, result.AddRange(maybeItem) over an Option). One cycle therefore plays every item exactly once, so a 200-episode show still takes 10× the airtime of a 20-episode one. What it buys is anti-clumping: the small show is spread evenly instead of arriving in bursts, and each show plays chronologically. That is a different product from "airs as often". Recorded because the padding reads as equalization and this was misread once during #70's own design pass — the distinction is the entire justification for the issue.
• Plain Shuffle is already implicitly weighted by collection size (Fisher–Yates over flattened items), which is why "just use Shuffle" isn't fair-share either.
• One new enum value, not two, and not a separate setting. Fair-share = WeightedShuffle with weights left at their default of 1, so the UI's "fair-share toggle" needs no second mechanism. A separate non-enum "distribution" setting was rejected: it would add an orthogonal axis every PlaybackOrder dispatch site must also consult, multiplying the blast radius below. Retrofitting weights onto ShuffleInOrder was rejected: it would silently change shipped users' output.
• Weights live on MultiCollectionItem AND MultiCollectionSmartItem (int Weight, DB default 1, dual-provider migration AddMultiCollectionItemWeight). The mirror is mandatory — omitting the smart item un-weights smart-collection members silently. The DB default must be 1, not 0: a 0 backfill would hand every pre-existing member to the rotation carrying a weight that means nothing on a share-of-airtime scale. (The enumerator clamps such rows to the floor so they rotate fair-share rather than vanish — but the backfill should be right at the source.) Rejected carriers: PlaylistItem (sequential engine; its Count/PlayAll already mean "how much of this source", and drain-N-consecutively A A A B is a different product from smooth interleave A A B A); CollectionItem (wrong grain — per media item, and the largest table).
• Applied on the ShuffleInOrder-shaped path only, because that is where source identity survives. MultiCollectionGrouper collapses sources into GroupedMediaItem + .Distinct(), so by the time the Shuffle path has its list, which source an item came from is gone. CollectionWithItems gains int Weight = 1; WeightedShuffleCollectionEnumerator consumes ShuffleSourceBuilder.GetCollectionItemsForShuffleInOrder unchanged — the schedule-entity-free entry point #380 reserved for this issue (no signature change, no god-factory, engines stay separate).
• Stateless. Smooth weighted round-robin (acc += weight; richest wins; pays the total) is a pure function of (Seed, Index), so it restores by replay like its siblings and needs no per-source counters (CollectionEnumeratorState has nowhere to put them). A rotation is sized so the source needing the most picks works through all its items at its share; smaller sources loop inside it — that looping is what makes equal weights mean equal airtime. Weight ratios are data, not state: a Reset build re-randomizes Playout.Seed (fresh within-source shuffle and start point) but the ratios hold identically.
• Ties break to the earliest source in list order (strict >), keeping the sequence deterministic.
• ScheduleAsGroup is not read by this order, unlike ShuffleInOrder, which merges every non-ScheduleAsGroup collection into ONE source. Here each CollectionWithItems is its own weighted source, which is the entire point — per-source weights are meaningless if sources are merged. Recorded because it means a persisted per-item flag quietly has no effect under this order.
• Within-source order is shuffled, not chronological (custom-ordered collections are still honored). Chronological inner order would make every rotation byte-identical, since source selection is deterministic — the reseed on wrap would change nothing and the avoid-an-immediate-repeat retry could never succeed. "Weighted in order" would be a separate order if wanted.
• Cross-engine exposure is closed by write-path validation, not by touching the silent fallbacks. An unhandled PlaybackOrder fails silently at five of six dispatch sites: Classic substitutes RandomizedMediaCollectionEnumerator (PlayoutBuilder's default:, // TODO: handle this error case differently?); PlaylistEnumerator has no default: arm, so the enumerator stays null and the item is dropped from the playlist (and null is legitimate there for SeasonEpisode with Count == 0, so nothing flags it); BlockPlayoutBuilder filters block items against an allow-list and continues past the rest; YAML/Scripted return Option.None, which their callers read as "no content". Only MultiCollectionGroup throws. A weighted order degrading to unweighted random is the worst case, because the output is supposed to look arbitrary. So the write path rejects WeightedShuffle everywhere it isn't handled — if it can't be persisted where it isn't handled, the silent sites never see it — and YAML/Scripted (which address orders by name, so Enum.Parse accepts it regardless) log a warning when an order falls through unhandled. Making those pre-existing fallbacks loud is a real but separate defect class: #403, an explicit non-goal here.
  • Exactly two writers persist a CALLER-SUPPLIED PlaylistItem.PlaybackOrder, and the second is not obvious. ReplacePlaylistItems is the expected one; CreateChannelFromLineup is the other — a lineup of 2+ entries is stored as a Playlist, and its own guard only covered MultiCollection entries, so a multi-entry lineup of plain collections slipped WeightedShuffle straight through to PlaylistEnumerator's null-drop. Both are gated. The full writer set, since "persisting writer" alone is the wrong axis: Add*ToPlaylist and TraktCommandBase do persist the field but hardcode it (Shuffle/Chronological), so no caller value reaches them; ReplaceBlockItems writes the different field BlockItem.PlaybackOrder (also gated); and PreviewPlaylistPlayout, PreviewBlockPlayout and Engine/PlaylistHelper build in memory without persisting. This bullet has now been wrong three times, each time in the same shape: it recorded the perimeter as complete when the gate covered only the writers already in hand (missing CreateChannelFromLineup); the first correction miscounted by conflating PlaylistItem with BlockItem; the second said "two persisting writers" when the true predicate is two writers that persist a caller-supplied order. The failure is always enumerating from a list instead of re-deriving from a grep — which is also how the "0-weight is filtered out" claims survived their own correction. Before trusting any "this order can't reach that engine" claim, grep every writer of each field separately and classify each as persists-caller-value / persists-hardcoded / in-memory. The non-obvious composite handler is the one that gets missed.
  • Weight is bounded at the write path (MultiCollectionItemWeight, 1..1000) and clamped again in the enumerator (EffectiveWeight). They do different jobs, which is why both stay: EF's HasDefaultValue(1) substitutes 1 for a 0 on INSERT (0 reads as "not set") but an UPDATE writes the 0 through, so create and update disagreed on the same input — the gate makes them agree and refuses values that mean nothing on a share-of-airtime scale (0, negative, or absurdly large). The clamp is what makes the rotation arithmetic safe for rows that predate the gate: it bounds every weight before the sum, so Sum(weights) cannot overflow regardless of what is stored. Historical note: an earlier revision of this PR filtered Weight > 0 instead of clamping, which silently deleted a 0-weight source from the channel; the clamp replaced it, and any comment still describing that filter is stale.
• Weight is returned on the multi-collection GET, not just accepted on write. The update replaces the item list, so a client that reads, edits a name, and writes back would silently reset every weight to the default if the read didn't carry it. Edits ride the existing Version token (If-Match/412, §7a).
• Scope: Classic engine only; no SPA (the schedule-editor weight UI is gated on #388). Plain single/smart collections (the GroupIntoFakeCollections path) carry no persisted weights — fair-share applies there by construction, and per-source weighting requires a multi collection. Auto-tune's per-member weights (#385/#386) need their own carrier: an auto-tuned channel is backed by one live SmartCollection, so its "sources" are members of a single collection, and a PlaylistItem cannot even reference a search query. Nothing here forecloses it — the enumerator reads weights off CollectionWithItems source-agnostically.

2026-07-17 — Docs-only CI skip gates STEPS in always-running required jobs, never if:-skips them (#416)

key: ci.docs-only-skip-steps · status: active · since: 2026-07-17 · supersedes: none · superseded-by: none Rule: A docs-only change must still run every required job (test, migrations) so their commit-status contexts always report; each heavy job runs scripts/ci-detect-docs-only.sh first and gates its real STEPS on if: steps.detect.outputs.docs_only != 'true', never if:-skips the whole job (an if:-skipped job reports skipped, not success, which branch protection may never unblock on). Detection biases toward running more on any doubt. Signals: docs-only CI skip, required-context branch protection, step-level gating vs job-level if: · paths: .gitea/workflows/docker-build.yml, scripts/ci-detect-docs-only.sh · issues: #416, #418, #420, #398 Mechanics: docs/ci-cd.md → "Docs-only skip"

A change touching only docs/** or *.md ran the entire docker-build.yml matrix (test, migrations incl. its mysql:8.4 service, functional-e2e, format, api-docs) — ~9 min of warm CI to validate Markdown. docker-build.yml had no path filtering.

Why not paths-ignore / an if:-skipped job — the trap. main's branch protection requires two contexts by name (Build & test (.NET), EF migration integrity (SQLite + MySql)). If a docs-only PR produced no run for them, those contexts never report and the PR can never merge — the naive fix bricks docs PRs instead of speeding them. A probe (throwaway PR #418) confirmed that on Gitea 1.25.4 an if:-skipped job reports commit-status state skipped (a distinct state, not success); how branch protection treats a skipped required context is not something we rely on.

The decision. Each heavy job (test, migrations, functional-e2e, build) runs scripts/ci-detect-docs-only.sh as its first post-checkout step (id: detect) and gates every real step on if: steps.detect.outputs.docs_only != 'true'. The job always runs and reports success in seconds on docs-only — so the two required contexts report unconditionally (safe by construction). Non-required jobs may skip freely (production proves a skipped non-required context doesn't block merge — build is skipped on every PR), so build skips its image steps on a docs-only push to main (docs aren't in the image); tag builds force docs_only=false so a release is never skipped. api-docs/format already self-short-circuit; docs-reminder/ decisions-guard/ci-image-pin keep running.

Detection biases toward running MORE. docs_only=true only when every changed path is docs; any code path, a tag build, a non-merge push, or an undeterminable diff → false (run everything). A false true would skip real tests on a code change (a correctness bug); a false false merely wastes CI. Trade-off accepted: migrations' mysql service still starts on a docs-only run (a services: container starts with the job regardless of step if:), but the 787-migration replay — the expensive part — is skipped.

Two adjacent redundancies are deliberately out of scope: the whole matrix re-running on a PR and again on the merge-to-main over identical code (#420), and the within-run triple dotnet build (#398). Full mechanism in ci-cd.md → "Docs-only skip".

2026-07-17 — Docs-only detect must be shallow-checkout safe: FETCH_HEAD + two-dot, not origin/main + three-dot (#416 follow-up)

key: ci.docs-only-detect-shallow-safe · status: active · since: 2026-07-17 · supersedes: none · superseded-by: none Rule: The docs-only detect script must diff against FETCH_HEAD (always resolves after git fetch, even shallow) using a two-dot tree diff — not origin/<base> with three-dot — because a fetch-depth: 1 shallow clone has no remote-tracking ref and no merge-base, which silently fails the original detect into docs_only=false (full matrix, no functional error). A CI-behavior change must be verified by measuring the effect (job durations), not just a green check. Signals: shallow clone, FETCH_HEAD, two-dot vs three-dot diff, fetch-depth 1 · paths: scripts/ci-detect-docs-only.sh · issues: #416, #422 Mechanics: docs/ci-cd.md → "Docs-only skip"; verified via a real shallow file:// clone reproduction

The #416 docs-only skip shipped (#422) safe but ineffective: every docs-only PR still ran the full matrix. Root cause — test/migrations check out fetch-depth: 1, and in a shallow clone origin/<base> has no remote-tracking ref and there is no merge-base, so the detect script's three-dot git diff origin/main...HEAD errored → || true → empty diff → the fail-safe returned docs_only=false → full matrix. Confirmed in a real shallow file:// clone (origin/main did not resolve; three-dot errored; git diff FETCH_HEAD HEAD returned the changed files correctly).

Decision: the detect diffs against FETCH_HEAD (always written by git fetch, resolves in a shallow clone) with a two-dot tree diff (no merge-base). api-docs/format were unaffected only because they use fetch-depth: 0 — a difference the first cut missed. Meta-lesson reinforced: a CI gating change can pass every local test and merge green while being a complete no-op in CI; only real-PR verification that measures the effect (job durations, not just a green check) catches it — which is exactly what #416's Done-when demanded. Fixed in the #416 follow-up PR.

2026-07-17 — Pre-push guard: don't push a file whose working-tree copy is uncommitted (H13, #416 session)

key: release.prepush-clean-worktree-guard · status: active · since: 2026-07-17 · supersedes: none · superseded-by: none Rule: A fail-open pre-push hook blocks a push when any file in the branch's diff vs origin/main also has uncommitted working-tree or index changes, since a stale-index commit (e.g. git reset --soft + git add over an edited-but-unstaged fix) can silently push, CI-test, and get reviewed a different tree than the one on disk. Scope is precise to pushed-diff files; escape hatch ETV_ALLOW_DIRTY_PUSH=1. Signals: working-tree vs committed-tree mismatch, stale index, pre-push hook, H13 · paths: .claude/hooks/prepush-clean-worktree-check.sh, .husky/pre-push · issues: #416 Mechanics: wired after the H11 rebase check in .husky/pre-push; same hook family as H11/H12 (#303)

A review fix (--no-renames) was edited into the working file and empirically verified there, but a git reset --soft + git add then committed the stale index, leaving the fix as an uncommitted working-tree diff. The push, the CI run, and a cold reviewer each saw a different tree: CI/push had the OLD code; the reviewer read the working file and "confirmed" a fix that never shipped. A PR went out still carrying the bug the review had cleared. Root cause: local build/test/review all operate on the working tree, but what ships is the committed tree — nothing enforced that they match.

Decision: a fail-open pre-push hook (.claude/hooks/prepush-clean-worktree-check.sh, wired into .husky/pre-push after the H11 rebase check) blocks a push when a file that is part of the branch's diff vs origin/main also has uncommitted working-tree or index changes. Scope is deliberately precise — only files in the pushed diff, so unrelated uncommitted scratch (or untracked files) never false-block. Fail-open on anything undecidable (not a repo, offline, no origin/main); deliberate escape ETV_ALLOW_DIRTY_PUSH=1. This is the mechanized half of the working-tree-vs-committed lesson; the review-process half (point reviewers at git show <sha>:<file>, never the bare working file) stays guidance. Same hook family as H11 (rebase-not-merge) / H12 (issue-qualification), same "#303 make the rule a hook, not prose to remember" throughline. Verified: dirty PR-file → block; clean tree → allow; dirty non-PR file → allow; escape hatch → allow.

2026-07-17 — Auto-Tune per-channel overrides reuse the Channel Builder advanced-options DTO; weights + bug-colour logo split out to #425 (#385)

key: sched.autotune-per-channel-overrides · status: active · since: 2026-07-17 · supersedes: none · superseded-by: none Rule: Auto-Tune per-channel overrides reuse the Channel Builder's advanced-options DTO verbatim; per-source weights and bug-colour logo are deferred to #425. Signals: Auto-Tune, per-channel overrides, advanced-options DTO reuse · paths: CreateAutoTunedChannelsHandler, POST /api/v1/channels/auto-tune · issues: #385, #383, #425, #283 Mechanics: CreateAutoTunedChannelsHandler.CreateOne; CreateChannelFromLineupAdvancedOptionsRequest

The Auto-Tune DetailPanel (#383) makes each proposed channel individually editable before bulk-create. The backend for that (#385) split cleanly along a "structural cost" line, and only the additive half shipped here; the rest is deliberately deferred rather than forced.

• Shipped now (additive, over the frozen /api/v1): POST /api/v1/channels/auto-tune's AutoTunedChannelRequest gained three optional per-channel fields — templateId, advanced, and an uploaded logo image. Omitting each keeps PR1 behavior exactly (batch template, axis-derived playback order, on-the-fly fallback logo), so the change is backward-compatible and the older positional {axis, value, name, number} form still binds.

  • advanced reuses the manual Channel Builder's CreateChannelFromLineupAdvancedOptionsRequest verbatim — the same 24-field override set, the same ToCommand(), and the same advanced.X ?? template.X stamp-at-create contract that POST /api/v1/channels/from-lineup already honors. Auto-tune is now just a second caller of that wire contract; we did not mint a parallel 24-field DTO. The one auto-tune-specific rule: the axis default (SeasonEpisode for a single show, Shuffle for a genre) fills PlaybackOrder only when the caller left it null, so an explicit per-channel order wins but an unset one is never dropped.
  • logo is the uploaded channel image, forwarded to CreateChannelFromLineup.Logo (persisted as an ArtworkKind.Logo artwork) and run through ArtworkContentTypeModel.Sanitized() at the request boundary — the same stored-XSS defense (#283) the Channel Builder uses; a hostile content type never reaches the command.
  • Per-channel independence is preserved: templateId/advanced/logo are resolved per channel inside CreateAutoTunedChannelsHandler.CreateOne, so one channel's bad override still yields a per-channel Failed/Skipped outcome without aborting the batch.

• Deferred to #425 — per-source rotation weights + query corrections (exclude / add-untagged). This is a structural redesign, not effort: #70's WeightedShuffle reads weights only off MultiCollectionItem/MultiCollectionSmartItem rows, but an auto-tuned channel is backed by a single SmartCollection (→ GetFakeMultiCollectionCollections, every fake group forced to Weight = 1), which gives fair-share but cannot express differing per-source weights. Honoring them requires auto-tune to build a MultiCollection of per-source SmartCollections (one query per weighted source), which contradicts the documented "one live query per channel" design and lands new structure in the scheduling subsystem. That is the [PLAN-MODE] design call the #385 body flagged; it belongs in its own issue with a recorded design decision, so it moved to #425 (consumed by the SPA #386).

• Deferred — bug initials + fallback colour generated logo. The generated logo (/iptv/logos/gen) is a stateless on-the-fly render used by both the XMLTV <icon> and the FFmpeg WatermarkSelector bug, with no persisted bug-initials/colour state on Channel. Making it configurable needs either new Channel columns (a dual-provider migration) wired through the watermark pipeline, or create-time artwork-file materialization — neither is the additive plumbing this slice was scoped to, and it is a channel-wide capability rather than an auto-tune concern. Left for its own issue / the SPA branding work; the uploaded logo above already covers the on-screen bug for channels that supply an image.

2026-07-17 — Health-check remediation is server-declared {Kind, Target} on an additive DTO; the SPA acts on it (#164)

key: api.healthcheck-remediation-dto · status: active · since: 2026-07-17 · supersedes: none · superseded-by: none Rule: Health-check remediation is server-declared {Kind, Target} metadata on an additive DTO field; the SPA renders/acts on it, it doesn't derive labels itself. Signals: health checks, remediation, AppRoute/ExternalDoc · paths: HealthCheckResponseModel, HealthCheckLink · issues: #164, #286, #108 Mechanics: HealthCheckResponseModel.Remediation; Application Mapper.GetStatus

#164 asked to make the ~14 health checks actionable — the Dashboard health panel showed problems with no way to investigate or fix them. Two structural decisions came out of it.

Remediation is server-declared metadata, not SPA-derived. Each check that has a fix knows where the fix lives, so the check declares it. The domain HealthCheckLink grew from (string Link) to (string Target, HealthCheckLinkKind Kind) with Kind ∈ {ExternalDoc, AppRoute} and two factories (HealthCheckLink.ExternalDoc(url) / HealthCheckLink.AppRoute("/app/...")). Only the 4 checks that built links and the API mapper touched .Link, so the widening was local. The SPA then acts on the kind: AppRoute → client-side navigateToPath(target) button; ExternalDoc → new-tab anchor. The human label is derived SPA-side from the route (a small lookup + prettified fallback) rather than sent over the wire — keeping the DTO minimal.

The DTO evolved additively (/api/v1 is frozen-additive, #286). HealthCheckResponseModel kept its existing Detail and gained Brief (← the domain BriefMessage the old mapper silently dropped) and Remediation { Kind, Target } (a nested HealthCheckRemediationResponseModel). The old flat string? Link is kept and still populated (mirrors Remediation.Target) but documented deprecated — we don't remove a frozen field, and existing consumers keep working. Remediation.Kind is a plain string ("ExternalDoc"/"AppRoute") mapped in the Application Mapper exactly like Status ("pass"/"fail"/…), not a wire enum — matching the established pattern for that DTO.

Three defects the audit surfaced, fixed here. (1) The Application Mapper.GetStatus threw ArgumentOutOfRangeException on NotApplicable; the handler filters NotApplicable before mapping so it was latent, but the mapper is now total (defense-in-depth — a future caller that skips the filter can't 500 the endpoint). InternalsVisibleTo("ErsatzTV.Tests") was added to the Application assembly (mirroring Core's precedent) to unit-test that totality directly. (2) Two checks linked to stale Blazor routes (media/trash, search?query=…) — repointed to the SPA /app/trash and /app/search?query=… as AppRoutes. (3) A dead Open Classic UI → /system/health link lingered in SettingsScreen (a #91b leftover that just 302'd to /app); removed (see blazor-route-parity.md Section 4 correction).

Actionable checks that had no link gained an AppRoute (metadata → /app/libraries, empty schedules → /app/schedules, HW-accel / VAAPI → /app/ffmpeg-profiles, FFmpeg reports → /app/settings). Pure-noise / no-clean-action checks (UnifiedDocker, MacOsConfigFolder, FFmpegCapabilities, the Info-tier nags) were left untouched — semantic-tier changes (e.g. adding a Pass path, demoting a nag) were deliberately not bundled into a remediation-UX PR.

Deferred (own issue): a TTL cache for PerformHealthChecks (#108 — every GET /api/v1/health re-runs all 14 checks, 4 shelling out to ffmpeg, and the existing summary cache is write-only dead code). Orthogonal to the UX; filed separately so a SPA-polled health panel gets a cache before it polls.

2026-07-18 — Auto-Tune DetailPanel SPA: reusable SlideOver + shared advanced-options model; decorative panes dropped to match the backend (#386)

key: spa.autotune-detailpanel-slideover · status: active · since: 2026-07-18 · supersedes: none · superseded-by: none Rule: The Auto-Tune DetailPanel SPA is a reusable SlideOver primitive sharing useOverlayBehavior with Dialog, plus a shared advanced-options model extracted from ChannelBuilder; decorative panes without backend support are dropped. Signals: Auto-Tune DetailPanel, SlideOver, shared advanced-options hook · paths: web/src/components/overlay.tsx, web/src/builder/advancedOptions.tsx · issues: #386, #384, #385, #425, #135 Mechanics: spa-conventions.md §11; useAdvancedOverrides hook

The SPA half of the Auto-Tune per-channel editor. It builds only what the shipped /api/v1 surface (#384 members read, #385 per-channel templateId/logo/advanced) can actually carry, so the panel never presents a control with nowhere to send its value.

• New reusable primitive SlideOver (web/src/components/overlay.tsx), sharing one useOverlayBehavior hook with Dialog (focus/scroll-lock/Escape/scrim). Right-edge panels are a recurring need; this is the seam, not a screen-local drawer. See spa-conventions §11.
• Advanced-options logic is shared, not re-implemented — the AdvancedPanel internals in the 84 KB ChannelBuilder.tsx were extracted to web/src/builder/advancedOptions.tsx (enum catalogs, ADVANCED_KEYS, effectiveValue, and the INHERIT/omit useAdvancedOverrides hook). ChannelBuilder now imports them with zero behavioral change (its test suite passes byte-for-byte); the DetailPanel writes its own field JSX over the same hook. The #135 "inherit = omit, no None option" contract therefore has a single implementation. Field layout stays per-screen (presentation, not logic) — the deliberate, stated deviation from full component reuse.
• Shipped panes: identity (name/number + uploadArtwork(_, 'logo') dropzone), Playback (Shuffle → advanced.playbackOrder, Always-playing → advanced.playoutMode, merged into advanced only when diverged from the template), per-channel template picker, the Advanced disclosure, a lean read-only Query&size (order-from-axis + est items + effective streaming mode), and a read-only Content-sources member list via GET /members.
• Dropped as backend-less decoration (the prototype had them; the wire contract does not): the MiniEpg "example schedule", the bug-initials/colour generator, and the "generated smart-collection query" text — the proposal DTO carries no query string, so rendering one would be fabricated. Deferred to #425 (its own end-to-end slice): the per-source rotation-weight steppers and exclude/add-untagged corrections; the Content-sources pane shows a "#425" hint so its read-only state reads as intentional.
• Unsaved-changes guard is screen-scoped (spa-conventions §8/§11): per-channel edits live in AutoTuneScreen draft state until bulk-create, so closing the panel keeps them (an "Edited" row badge makes that visible) and only screen navigation / full-page unload with uncommitted edits confirms.

2026-07-18 — SmartCollection rule builder: compile-only closed subset, no stored AST, one-level nesting (#176)

key: spa.smartcollection-rule-builder · status: active · since: 2026-07-18 · supersedes: none · superseded-by: none Rule: The SmartCollection visual rule builder compiles to/from a closed subset of the Lucene grammar over the existing stored query string — no new AST, one level of group nesting. Signals: SmartCollection, rule builder, Lucene compile/parse · paths: web/src/builder/rules/, compile.ts, parse.ts, roundtrip.test.ts · issues: #176, #69 Mechanics: GET /api/v1/search/fields; api-conventions.md; spa-conventions.md §12

The SmartCollection create/edit dialog gained a visual rule builder (web/src/builder/rules/) alongside the existing raw-Lucene textarea. The SmartCollection still stores a plain Lucene query string — no new stored rule AST, no schema change. The builder compiles its in-memory rule tree into a closed subset of the Lucene grammar (compile.ts) and parses exactly that subset back out (parse.ts, the exact inverse — returns null, not a best-effort guess, for anything outside the subset); escaping is total, so any builder-authored query round-trips losslessly, proven by a 500-tree property test (roundtrip.test.ts, including Lucene special characters). Opening an existing SmartCollection tries the parse first and falls back to raw-text mode on null (fuzzy queries, boosts, mixed AND/OR at one nesting level, or nesting deeper than one level).

Why compile-only over persisting an authoritative rule AST: an AST would still need a Lucene→rules parser to open every pre-existing free-text query — including every query the Auto-Tune feature (#69) generates — so the AST would buy almost nothing (it still can't represent arbitrary hand-written Lucene) while costing a dual-provider EF migration and a second source of truth to keep in sync with the Lucene grammar. Compile-only keeps the query string as the single source of truth and treats the builder as a structured editor over it, not a new storage model.

One-level-nesting "Kodi" model. types.ts defines a top Group (match: all|any) over Rules and/or one level of sub-Groups — enough to express type:movie AND (genre:Horror OR genre:Thriller), which covers the smart-playlist patterns Kodi-style rule builders are known for. Arbitrary/recursive nesting was scoped out as YAGNI; revisit only if a real query needs it.

Field vocabulary comes from a new catalog endpoint, not a hardcoded list. GET /api/v1/search/fields (read-only, MCP-introspectable; see api-conventions.md) returns the curated, typed, labeled field set derived from LuceneSearchIndex — name/label/type/group/values — and is the single source of truth the builder's field pickers (fieldCatalog.ts's useSearchFields hook) and operator/value-input choices are driven from, so the builder's vocabulary can't drift from what the index actually supports.

Deferred as separate follow-up issues (explicitly out of scope for #176): facet-value typeahead for value inputs, relative-date operators, nesting deeper than one level, and inline adoption of RuleBuilder by ChannelBuilder / Auto-Tune (it was built reusable for exactly that reuse — see spa-conventions.md §12).

2026-07-18 — Auto-Tune per-source weights ride #70's MultiCollection machinery; created at tune time, not a post-hoc PUT (#425)

key: sched.autotune-per-source-weights · status: active · since: 2026-07-18 · supersedes: none · superseded-by: none Rule: Auto-Tune per-source rotation weights and query corrections are supplied at bulk-create time via #70's MultiCollection/SmartCollection machinery, not a post-hoc PUT. Signals: Auto-Tune, per-source weights, MultiCollection, WeightedShuffle · paths: AutoTunedChannelRequest, OwnedByChannelId migration · issues: #425, #70, #383, #386, #385 Mechanics: AddCollectionOwnedByChannelId migration; WeightedShuffleCollectionEnumerator

Per-source rotation weights (3× Show A, 1× Show B) and query corrections (exclude / add-untagged) for an auto-tune channel are supplied at bulk-create time — an optional sources: [{sourceId, weight, excluded}] list on each AutoTunedChannelRequest (the same DetailPanel-wizard surface #385 added its per-channel advanced/templateId/logo to). There is no post-hoc PUT .../weights, no lazy upgrade/downgrade, and no idempotent desired-state handler: the auto-tune DetailPanel (#383/#386) is a create-wizard, and #425's Done-when is "create → built playout". (An earlier plan draft assumed a PUT on an existing channel; the shipped flow is create-time, matching #385.)

Structure — Option A (reuse #70), not a new fake-collection weight path. When any source is customized (a non-default weight, an exclusion, or an added out-of-axis id), the channel is backed by a system-owned MultiCollection of per-source SmartCollections, weights on MultiCollectionSmartItem.Weight, and its single-item lineup points at the MultiCollectionId with PlaybackOrder.WeightedShuffle — the exact path WeightedShuffleCollectionEnumerator already consumes (GetMultiCollectionCollections forwards the per-row weight). Rejected: threading a weight map through GroupIntoFakeCollections (the fake-collection path a lone SmartCollection takes, which hardcodes weight 1) — it derives its group keys at runtime, is shared with the unrelated FillWithGroupMode, and would need a parallel weight-persistence home. When no source is customized (all weights 1, nothing excluded/added) the channel keeps the #69 single-SmartCollection fair-share shape — cheaper, and identical output for TV since the fake path already groups per show.

Discriminators. A source's member query is discriminator-only (membership is fixed at tune time): TV uses type:episode AND show_title:"X" (episode docs carry no parent-show id in the index — show_title is the only per-show field, the same one #69's TvShow axis already uses; a post-create rename empties the member until re-tuned), and movies use the stable, rename-proof type:movie AND id:{mediaItemId} (a movie is the played item). The remainder is ({base}) AND NOT ({d1} OR {d2} …) over every materialized ∪ excluded discriminator — a partition of the base set, so no item is counted twice or dropped. Exclude = omit the member and keep it in the NOT-list (else its items leak back through the remainder); add-untagged = an ordinary member whose id isn't in the base set (no genre clause, so it just airs).

Materialization bound is axis-dependent — "weight N" means N× each other source. TV materializes every base show as its own member (un-weighted shows keep per-show fair-share; a single merged remainder would regress them to item-proportional, so a 200-episode show would swamp a 20-episode one) plus one live remainder at weight 1 for shows/episodes added after tune-in (empty at create → harmlessly skipped by WeightedShuffleCollectionEnumerator's ActiveSources filter). MovieGenre materializes only the touched movies (weighted or added) and leaves every un-touched base movie in ONE remainder whose weight = its member count — exactly equivalent to materializing each movie individually, because the fake path already pools movies uniformly, without hundreds of rows. Cost note: a large TV genre materializes one SmartCollection per show (dozens–hundreds), each a cheap stored term query; a future optimization could cap/warn.

Ownership + lifecycle. The MultiCollection and its member/remainder SmartCollections carry a nullable OwnedByChannelId (dual-provider migration AddCollectionOwnedByChannelId, indexed). Owned rows are hidden from the user-facing collection lists and cascade-cleaned when the channel is deleted (the ProgramScheduleItem → MultiCollection cascade removes the dangling flood item). Names embed a per-create token (at-mc:{token}, at:{token}:{n}) because both names are unique varchar(50) and the channel id isn't known until CreateChannelFromLineup runs; ownership is stamped immediately after. Non-weighted (#69) channels set no ownership, so their pre-existing orphan-on-delete behavior is unchanged. The create is non-atomic across the two handlers (mirrors #69) with best-effort rollback of the artifacts on channel-create failure.

2026-07-18 — Search all-items is paged to cap DoS exposure; SPA add-all pages to completeness (#293)

key: api.search-allitems-paging · status: active · since: 2026-07-18 · supersedes: none · superseded-by: none Rule: GET /api/v1/search/all-items is paginated (capped page size, Totals field) to bound DoS exposure; the SPA add-all flow pages to completeness instead of relying on an unbounded response. Signals: search all-items, pagination, DoS hardening · paths: SearchController.SearchAllItems, LuceneSearchIndex, web/src/api/search.ts · issues: #293, #285, #308, #384 Mechanics: MaxAllItemsPageSize/DefaultAllItemsPageSize clamps; getAllSearchItemIds

GET /api/v1/search/all-items (SearchController.SearchAllItems → QuerySearchIndexAllItemsHandler) fired ten index searches with limit: 0 (= "return every hit", LuceneSearchIndex line ~244), so a single broad query (e.g. one matching the whole library) materialized every matching doc across all ten media kinds into ten List<int> buckets and serialized them in one response — unbounded work per request. #285 closed the original unauthenticated exposure (the endpoint is now behind Api:RequireKeyForReads, default true); the residual was DoS-hardening against an authenticated caller with a very broad query. Deferred from #285 because the SPA "add all to collection/playlist" flow materializes the full id set before the add POST, so a naive hard cap would silently truncate "add all".

Decision (issue option (a), operator-confirmed): paginate the endpoint and teach the SPA add-all flow to page to completeness — rather than option (b) (a generous cap + truncation signal). Chosen because "add all" must stay complete for real use, and it matches the sibling GET /api/v1/search / GET /api/v1/channels/auto-tune/members (#384) paging convention already in the codebase.

• Endpoint (additive). SearchAllItems gains optional pageNum (0-based) + pageSize, clamped exactly like the §1 Logs / sibling Search precedent: pageSize = Math.Clamp(pageSize, 1, MaxAllItemsPageSize) with MaxAllItemsPageSize = 1000, DefaultAllItemsPageSize = 500. pageNum is clamped Math.Clamp(pageNum, 0, MaxAllItemsPageNum) with MaxAllItemsPageNum = 2_000_000 — the upper bound keeps pageNum * pageSize (the search skip) inside int range so an absurd page number can't overflow to a 500 (the sibling Search only floors at 0; the all-items endpoint hardens the upper bound too since this is a DoS-hardening change). The clamp is applied per media kind (a page returns ≤ pageSize ids of each of the ten kinds), so one response is bounded to ≤ 10 × pageSize ids. QuerySearchIndexAllItems carries PageNum/PageSize; the handler passes skip = PageNum × PageSize, limit = PageSize into ISearchIndex.Search (native skip/limit) and reads SearchResult.TotalCount (the true total, free) per kind.
• Response (additive, frozen-v1-safe). The ten …Ids buckets are unchanged; a new non-null nested Totals (SearchResultAllItemsTotalsResponseModel, ten …Count ints) is added so a client knows how many ids exist per kind and can page to completeness. Nothing is removed or retyped (#286 additive-only holds).
• Deliberate default-behavior change. A caller that sends no pageSize now gets one page (default 500 / kind) plus Totals, not the entire id set. This is the security change the issue asks for; it is safe here because the only in-repo consumer is the SPA (updated in the same PR) and any external/MCP caller can read Totals and page. Recorded as intentional, not a regression.
• SPA pages to completeness. web/src/api/search.ts getSearchAllItems(query, pageNum, pageSize) gains the params; a new getAllSearchItemIds(query) loops pages (requesting pageSize = 1000, the server max), accumulating every bucket until each kind has collected its Totals count (with an empty-page safety break against total-count drift), and returns the merged SearchAllItemIds. SearchScreen.addAll calls it instead of the single-shot fetch; the #221 stale-query guard and the single add POST are unchanged.
• Out of scope (unchanged): the add POST itself still accepts the full merged id set in one request body — bounding that surface is a separate concern (see #308 for the add path); #293 is the GET.

2026-07-18 — Collapsible sidebar + nav-group accordions: two ctv-sidebar-* localStorage keys, labeled groups default-collapsed (#396)

key: spa.sidebar-collapsible-accordions · status: active · since: 2026-07-18 · supersedes: none · superseded-by: none Rule: The shell sidebar's collapse + nav-group-accordion state persists under two hyphenated ctv-sidebar-* localStorage keys (matching the repo's ctv- convention, not the prototype's dotted names); labeled groups default-collapsed. Signals: sidebar, collapsible nav groups, localStorage keys · paths: web/src/app/AppShell.tsx, web/src/app/sidebarState.ts · issues: #396 Mechanics: spa-conventions.md §5d; ctv-sidebar-collapsed / ctv-sidebar-groups keys

The shell sidebar (web/src/app/AppShell.tsx) gained (a) a header toggle that collapses it to a 60px icon rail and (b) collapsible accordions per labeled nav group (Media, System); the unlabeled Primary group is always open. Mirrors the Claude Design prototype's updated Sidebar.

• State lives in a small hook, not App. web/src/app/sidebarState.ts useSidebarState() owns both pieces of state + persistence; AppShell consumes it (nothing else needs it) and stamps ctv-app-shell-collapsed on the shell root so the collapse is CSS-driven from one class.
• Persistence keys use the established ctv- hyphen convention, NOT the prototype's dotted names. The issue quoted ctv.sidebar.collapsed / ctv.sidebar.groups, but every existing client-local pref is hyphenated (ctv-theme, ctv-logs-page-size — spa-conventions §5d), so we use ctv-sidebar-collapsed ("1"/"0") and ctv-sidebar-groups (JSON {groupKey: boolean}, boolean = collapsed). Deliberate deviation from the issue's literal key text in favour of the repo convention the issue itself points to; helpers validate/parse defensively (bad JSON / non-boolean values → default).
• Labeled groups default to COLLAPSED (absent ctv-sidebar-groups entry ⇒ collapsed), so a fresh load shows only Primary — matching the prototype ("default-collapsed, leaving only Primary visible"). A behavior change for existing users; App.test.tsx's shell/nav suite seeds the two groups open because it clicks Media/System nav links directly (the accordion behavior is covered in its own describe).
• Accordions apply only in the expanded sidebar. In the rail, group-collapse is ignored — every item renders as an icon (label kept in the a11y tree via an sr-only span so the accessible name/tests survive; surfaced as a native title tooltip), groups separated by a hairline divider, numeric badges shown as a corner dot. The active-route indicator (left rail bar + active background) works in both states.
• Group keys are explicit + stable (SidebarNavGroupDefinition.key: 'media', 'system') rather than derived from the label, so renaming a label doesn't silently orphan persisted state.
• No route/screen was added or redirected (shell-chrome only), so no blazor-route-parity.md change.

2026-07-18 — Unsupported PlaybackOrder is loud at build time; a declared support matrix and tripwire test make new orders safe by construction (#403)

key: sched.playbackorder-support-matrix · status: active · since: 2026-07-18 · supersedes: none · superseded-by: none Rule: Every build-time dispatch site logs a loud (non-fatal) warning on an unsupported PlaybackOrder, and a declared PlaybackOrderSupport matrix + partition tripwire test makes adding a new order safe by construction. Signals: PlaybackOrder, support matrix, build-time dispatch · paths: ErsatzTV.Core/Scheduling/PlaybackOrderSupport, PlaylistEnumerator.Create, BlockPlayoutBuilder · issues: #403, #70 Mechanics: PlaybackOrderSupportTests (partition assertion)

#70 closed the persistence hole for WeightedShuffle (the write path rejects it on the engines that can't handle it) and made YAML + Scripted log a warning; MultiCollectionGroup already threw. It left the three still-silent build-time dispatch sites — the ones this issue names — as an explicit non-goal. #403 makes those loud and adds the by-construction net.

• Loud, but NON-FATAL, at every build site. On an order it doesn't handle, each site now logs a Warning (naming the order + engine + the fallback taken) instead of silently substituting/dropping/ skipping: Classic's PlayoutBuilder default: arm (was // TODO, silently returned Random), the PlaylistEnumerator.Create switch (had no default: arm → null enumerator → item dropped), and BlockPlayoutBuilder's allow-list continue (silent skip). The actual fallback is preserved — a live channel airing wrong-but-something beats going dark on one misconfigured item — so scheduler goldens do not move. This matches the log-and-continue posture #70 already shipped for YAML/Scripted.

  • PlaylistEnumerator.Create was static with no logger, which is why the playlist drop was unreportable. It gained an optional Option<ILogger> logger = default (mirrors the existing GetStartTimeAfter(..., Option<ILogger>.None) pattern); the three callers that have a logger pass it, the rest default to None.
  • BlockPlayoutBuilder's GetEnumerator switch gained an explicit PlaybackOrder.Random arm. Random is in Block's allow-list but previously reached an enumerator only via the switch's coincidental _ => Random fallback; the fallback is now a loud helper (defensive — the allow-list should make it unreachable).

• Safe-by-construction net: a declared support matrix + a tripwire test. PlaybackOrderSupport (ErsatzTV.Core/Scheduling/) declares, per SchedulingEngineKind (Classic / Playlist / Block / Yaml / Scripted), BOTH a Supported and an Unsupported set. PlaybackOrderSupportTests asserts the two sets partition every PlaybackOrder value (union total, intersection empty) for every engine — so adding a new enum value lands in neither set and fails the test until it is consciously classified and wired into the matching dispatch switch. Both sets are hand-maintained on purpose: deriving Unsupported as "everything not supported" would let a new order fall through silently, which is the exact defect being killed. The matrix is not pure test scaffolding — BlockPlayoutBuilder consumes it at runtime for its allow-list (replacing the previously duplicated inline list).

• Write-path rejection is deliberately UNCHANGED. #70's per-engine guards already close the real persistence exposure, and the decisions log records that the "which order reaches which engine" perimeter has been wrong three times — always by enumerating from a list instead of grepping every writer. Broadening write-path rejection here would risk newly-400ing configs that currently save-and-fall-back, for no safety gain, so it was left alone. This PR hardens the build-time sites and adds the tripwire.

• Reverse-mappings deferred (a different axis). The three _ => PlaybackOrder.None arms that map an enumerator class back to a PlaybackOrder for PlayoutHistory were left alone: that path is reached in normal operation by legitimately-supported enumerator types (ShuffleInOrderCollectionEnumerator, SeasonEpisodeMediaCollectionEnumerator) that simply aren't reverse-mapped, so making it "loud" would emit false-positive warnings. Completing that reverse map is a separate concern from "an unsupported order degrades silently" and is not part of #403's scope.

2026-07-18 — CI build-once was measured and rejected; keep the #420 tree-skip

key: ci.build-once-rejected · status: active · since: 2026-07-18 · supersedes: none · superseded-by: none Rule: CI build-once (a shared compile artifact across jobs) was implemented, measured, and rejected for a 40-85% wall-clock regression; keep the #420 cross-run tree-identity skip instead. Signals: CI build-once, artifact tar/transport cost, tree-identity skip · paths: docs/ci-cd.md → Cross-run tree-identity skip · issues: #420, #398, #455 Mechanics: docs/ci-cd.md → Cross-run tree-identity skip; PR #455 measurement

Build-once (a compile job producing a single artifact, consumed by test/migrations/ functional-e2e via --no-build) was fully implemented and went green on CI (PR #455, run 830), then rejected on measurement: it traded a ~12% slot-occupancy saving for a ~40–85% per-run wall-clock regression.

• Why it regressed. The bin+obj artifact is 2.5 GB raw / 972 MB gz; tar alone costs ~82s CPU plus ~180s transport, consuming most of the ~465s the shared compile was meant to save. Worse, compile serializes before migrations' long ef-replay, which is pure DB work a shared build cannot shorten — the bottleneck was never the redundant compiles.
• Incidental finding worth recording. actions/upload-artifact@v4 does not work on this Gitea instance — it throws GHESNotSupportedError, because the @actions/artifact v2 client library rejects any non-github.com host. @v3 is required for any future artifact use here.
• Kept: the #420 cross-run tree-identity skip (docs/ci-cd.md → Cross-run tree-identity skip). It is independent of build-once — it only skips redundant work on identical-tree main pushes, at zero wall-clock cost, rather than trying to share a build across jobs. Don't re-attempt build-once unless the runner's artifact storage or network changes materially.

Refs: #398 (closed), #420, PR #455.

2026-07-18 — Never-scanned LastScan surfaces as null at the API boundary, not the 0001-01-01 MinValue sentinel (#409)

key: media.lastscan-null-boundary · status: active · since: 2026-07-18 · supersedes: none · superseded-by: none Rule: A never-scanned LastScan surfaces as null at the API/MCP boundary, not the 0001-01-01 MinValue sentinel — enforced by an ongoing read-boundary coercion plus a one-time data migration cleanup. Signals: LastScan, MinValue sentinel, API-boundary honesty · paths: GetAllMediaSourcesForApiHandler.NormalizeLastScan, MediaSourceRepository · issues: #409 Mechanics: NullOutNeverScannedLastScan migration; LibrariesScreen.tsx hasScanned removal

Library.LastScan / LibraryPath.LastScan are DateTime?; a never-scanned library is null at runtime for a freshly-created row. But the 0001-01-01 00:00:00 MinValue sentinel still appears in the DB from two sources — and the second is ongoing, not historical:

1. Old Reset_* migrations wrote it via raw SQL (UPDATE Library SET LastScan = '0001-01-01 00:00:00').
2. Live code still writes it today: MediaSourceRepository sets library.LastScan = SystemTime.MinValueUtc on the Plex/Jellyfin/Emby remove-and-recreate (disable-sync) flows (MediaSourceRepository.cs:480/611/976). So the sentinel keeps being written during normal use.

GetAllMediaSourcesForApiHandler projected l.LastScan straight onto its DateTime? DTO, so that sentinel leaked to API/MCP clients as a fake midnight timestamp — the SPA papered over it with a client-side year<1900 heuristic (#409 first pass). Decision: the API is the right place to be honest, so never-scanned reports as null for API/MCP parity with the UI, via two layers:

• Read-boundary coercion — the load-bearing, ongoing guard (provider/history-independent): GetAllMediaSourcesForApiHandler.NormalizeLastScan maps any < 2000-01-01 value to null. Because source #2 above keeps writing the sentinel, this coercion is permanent, not a stopgap — a migration-only fix would regress the next time a user toggles a library's sync off.
• Data migration (NullOutNeverScannedLastScan, dual-provider): a one-time cleanup of the historical residue — UPDATE Library/LibraryPath SET LastScan = NULL WHERE LastScan IS NOT NULL AND LastScan < '2000-01-01'. Data-only (empty Up/Down otherwise, both TvContextModelSnapshot.cs byte-identical). The < '2000-01-01' predicate matches the 0001-01-01 sentinel robustly on both providers (ISO-text compare on SQLite, whatever the out-of-range zero date stored on MySQL — where no Reset_*LastScan migration ever ran, so it's a safe no-op there) without depending on the exact stored bytes; no real scan predates ErsatzTV. Down is a no-op — the original sentinel is unrecoverable and worthless.

GetAllMediaSourcesForApiHandler is the only API/MCP-facing consumer of LastScan (grepped LastScan under ErsatzTV.Application/**/Queries and ErsatzTV/Controllers); the other reads are internal scanner code that coalesces to SystemTime.MinValueUtc for its own non-nullable DateTimeOffset scan-comparison needs and never serializes it to a client. The DTO field was already DateTime?, so the OpenAPI schema is unchanged (no regen). The SPA's hasScanned heuristic in LibrariesScreen.tsx was removed — both call sites revert to a plain null/truthy check now that the API is honest. (Follow-up option, not done here: have MediaSourceRepository write null instead of MinValue so the data is clean at rest too; the read coercion makes that non-urgent.)

2026-07-19 — WeightedShuffle SPA: weights edited on the multi-collection, order offered only on classic MultiCollection schedule items; fair-share is a reset not a mode (#404)

key: sched.weightedshuffle-editor · status: active · since: 2026-07-19 · supersedes: none · superseded-by: none Rule: WeightedShuffle per-source weights are edited on the multi-collection editor (property of the MultiCollection), while the WeightedShuffle order itself is offered only on classic MultiCollection schedule items; fair-share is a "reset weights to 1" action, not a stored mode. Signals: WeightedShuffle SPA, multi-collection weights, fair-share reset · paths: web/src/.../itemRules.ts MULTI_COLLECTION_ORDERS, itemsFromMultiCollection/toItemRequest · issues: #404, #70, #402 Mechanics: spa-conventions.md §4 (replace-all-DTO trap); fillWithGroupModeEligible exclusion

The UI half of #70 (backend + API shipped in PR #402). No new endpoint or DTO — weight was already on MultiCollectionItemRequest/…ResponseModel and WeightedShuffle already in the PlaybackOrder enum; this is purely SPA (+ docs).

• Two surfaces, split by where each datum lives. The per-source weights are a property of the MultiCollection, so they are edited in the multi-collection editor (/app/multi-collections), not on the schedule item. The order (WeightedShuffle) is a property of the schedule item, so it is added to the classic schedule item's Playback Order options. Putting weights on the schedule item was rejected: the same multi-collection can be referenced by many schedule items, and weights are shared, not per-reference.
• WeightedShuffle is offered ONLY for collectionType === 'MultiCollection' (itemRules.ts MULTI_COLLECTION_ORDERS) — a meaningfulness scope, not a rejection mirror. Weights only exist on multi-collection members, so the order only does something with 2+ weighted sources; on a single collection the classic engine still accepts it (verified by live-E2E: PUT /schedules/{id}/items with a plain Collection + WeightedShuffle → 200) but it degrades to fair-share (≈ Shuffle), a confusing no-op — so the SPA doesn't offer it there. The rejection the #70 entry describes is on the separate playlist and block write paths (different engines); the playlist/block editors keep their own order lists (not MULTI_COLLECTION_ORDERS) and already omit WeightedShuffle, so nothing extra was needed there.
• WeightedShuffle joins ShuffleInOrder in the fillWithGroup exclusion. fillWithGroupModeEligible already excluded ShuffleInOrder; WeightedShuffle is excluded for the same structural reason — PlayoutBuilder splits a fill-with-group item into per-group enumerators scheduled one group at a time, which is incompatible with WeightedShuffle's whole-multi-collection per-source share of airtime. Offering the combination would silently not do what the name says.
• Fair-share is a "Reset to fair share" button, not a stateful toggle. decisions.md 2026-07-17 established that fair-share is not a separate mode — it is WeightedShuffle with all weights left at the default 1. So there is nothing to toggle on: the button just sets every source's weight to 1 (disabled when already there). A persistent toggle was rejected because "fair share" has no stored representation distinct from "the weights all happen to be 1".
• Weights round-trip through the editor draft or they silently reset. The multi-collection PUT replaces the whole item list, so weight is read in itemsFromMultiCollection and written in toItemRequest; dropping it would reset every source to 1 on the next unrelated save (rename, add a source). Covered by a round-trip test. This is the general replace-all-DTO trap now recorded in spa-conventions.md §4.
• Percentages are display-only; the wire format is the integer weight. A 3:1 weight shows as 75% / 25%, computed from the clamped weights; the request always carries the integer relative share (1..1000). The weight field is held as a string in the editor draft so it edits smoothly, clamped to the API validator's 1..1000 on blur and again at save — an out-of-range value never reaches the server as a raw 400. Input gained min/max/inputMode/onBlur passthroughs for this (reusable by #425's weight UI).

2026-07-19 — Health-check results are TTL-cached; ?refresh=true forces a fresh run (#431)

key: api.healthcheck-ttl-cache · status: active · since: 2026-07-19 · supersedes: none · superseded-by: none Rule: Health-check results are held in a 30s TTL cache inside HealthCheckService; a non-forced GET /api/v1/health returns the cached list, and ?refresh=true (or a forced internal caller) bypasses it to run fresh. Signals: health check caching, TTL, refresh query param · paths: HealthCheckService._memoryCache, api-conventions.md §1/§3b · issues: #431, #164 Mechanics: PerformHealthChecks(forceRefresh, ...); GET /api/v1/health?refresh=true

HealthCheckService.PerformHealthChecks re-ran all 14 checks on every call, four of which shell out to ffmpeg/ffprobe via CliWrap — so a bare GET /api/v1/health spawned ~4 subprocesses per request. The existing HealthCheckSummary cache was write-only (populated + published, never read back to short-circuit a re-run). Harmless while the SPA Dashboard health panel refreshes on-demand only, but a real cost the moment anything polls health (a status widget, an MCP client, monitoring). Split out of #164 as the orthogonal performance half.

• A short TTL cache of the full result list lives inside HealthCheckService. A _memoryCache entry ("healthcheck.results", TimeSpan.FromSeconds(30)) holds the last List<HealthCheckResult>; a non-forced call returns it directly on a hit, skipping both the 14 checks and the summary Publish. Chosen over "make the existing summary cache read-through" because the API returns the full per-check list, not the 2-int summary — the summary entry ("healthcheck.summary", read by GetHealthCheckSummary) is kept as-is (un-expiring) so its fallback behavior is unchanged.
• PerformHealthChecks gained a bool forceRefresh first parameter (interface signature change; one implementer, 3 live callers). forceRefresh: true bypasses the cache and repopulates it.
• The refresh surface is an optional ?refresh= query param on the existing GET, following the ?deep= bool-query-param exemplar (api-conventions.md §1/§3b) — additive, backward-compatible, no new endpoint. [FromQuery] bool refresh → GetAllHealthCheckResultsForApi(Refresh) → PerformHealthChecks(request.Refresh, …). The SPA "Refresh health" button calls /api/v1/health?refresh=true; the initial/poll load calls the bare path (cached). A separate POST …/refresh endpoint was rejected as unnecessary surface for a read.
• Who forces vs. who reads the cache: the API GET poll path reads the cache; the startup RunHealthChecksService and the troubleshooting support bundle force a fresh run (both want current state — startup is a cold cache anyway, and a diagnostic bundle should reflect now, not a ≤30s-old poll). The legacy GetAllHealthCheckResults handler is dead (no senders) and reads the cache.
• Thundering-herd on a cold cache was left out of scope (no request-coalescing lock): polling is sequential per client and the TTL collapses steady-state load, so at most a handful of exactly-simultaneous cold callers re-run — a once-per-30s edge, not the repeated per-request cost the issue targets. Recorded here so a later reviewer doesn't read the absence of a SemaphoreSlim as an oversight.

2026-07-19 — The format gate runs dotnet format whitespace . --folder, not the full solution format (#469)

key: ci.format-gate-folder-mode · status: active · since: 2026-07-19 · supersedes: none · superseded-by: none Rule: The blocking format CI job (and matching pre-commit hook) runs dotnet format whitespace . --folder --include <files> instead of loading the full MSBuild/Roslyn solution, cutting the gate from ~480s to ~0.5s with unchanged whitespace/charset coverage. Signals: dotnet format, folder mode, CI format gate · paths: .gitea/workflows format job, .editorconfig · issues: #469, #406, #311 Mechanics: dotnet format whitespace . --folder --verify-no-changes --include <files>

The blocking format CI job (and the matching Husky pre-commit hook) verify changed .cs files with dotnet format whitespace . --folder --verify-no-changes --include <files> instead of the previous dotnet format ErsatzTV.sln --no-restore --verify-no-changes --include <files>.

• Why. --include narrows which files are checked, never what gets loaded. The full recipe loaded the whole ~10-project MSBuild workspace and built a Roslyn compilation per project before checking a single line — a fixed cost independent of how few files changed. Measured ~480s for a whole-solution dotnet format locally (matching the issue's "7+ min"). --folder treats the tree as a plain folder of files and skips MSBuild/Roslyn entirely: ~0.5s, and it needs no dotnet restore, so the job's NuGet-cache + Restore steps were deleted. It also drops the job's ~3.95 GiB Roslyn heap (the #406 memory note about format not shrinking is now moot).
• Coverage is unchanged, not merely "good enough". Folder mode reads .editorconfig and enforces exactly the two things this gate exists for — whitespace (indent/EOL/trailing/final-newline) and charset (no UTF-8 BOM). Proven non-vacuous: exits non-zero with error WHITESPACE on an injected trailing-whitespace line and error CHARSET on a prepended BOM; exits 0 on a clean file. What it drops is the style/analyzer pass — but the full gate never enforced that either: a probe injecting a warning-severity naming violation (local_constants not ALL_UPPER) passed the full solution format (exit 0): the only .editorconfig rule above :suggestion/:none severity is that one naming rule, and naming violations have no dotnet format batch code-fixer, so --verify-no-changes reports no change regardless of severity. The analyzers that must block (NU1904, S3981) are enforced at compile time via WarningsAsErrors in Directory.Build.props, never by this job.
• Fix command for a violation: dotnet format whitespace . --folder --include <files>. The full dotnet format ErsatzTV.sln --include <files> is a superset (also applies style) and still works, so existing muscle memory and the #311 lore's dotnet format --include guidance are not broken.
• Lane left on ubuntu-latest. The job is now seconds-long and low-memory, so it could move to a lighter lane, but that re-touches the per-lane memory-cap accounting (#406/#604) and is a server-management capacity call — deliberately out of scope here.

2026-07-19 — CI test job reports a sampled true peak-anon, not cache-inflated memory.peak (#412)

key: ci.peak-anon-measurement · status: active · since: 2026-07-19 · supersedes: none · superseded-by: none Rule: The test job's headline memory figure is a sampled high-water mark of cgroup anon, produced by scripts/ci-peak-anon.sh; memory.peak and the end-of-job anon/file split are kept only as a cache-inflated reference. Signals: CI memory measurement · paths: scripts/ci-peak-anon.sh, .gitea/workflows/*.yml · issues: #412, #411 (prose-only predecessor, no standalone record — its memory.peak-headline approach is superseded by this record) Mechanics: scripts/ci-peak-anon.sh header; docs/ci-cd.md → CI build memory

Decision. The test job's memory instrument (added in #411) now reports a sampled high-water mark of the cgroup's anon memory as the headline figure, produced by scripts/ci-peak-anon.sh (a start step before the dotnet Build/Test/Coverage, a report step last). memory.peak and the end-of-job anon/file split stay in the output as a cache-inflated ceiling and a reference.

Why not just memory.peak. memory.peak is the high-water mark of memory.current, which charges reclaimable page cache to the cgroup alongside anon. A build does heavy NuGet/npm/obj/bin/coverage I/O, so cache can dominate the peak — and page cache is reclaimed under a tighter cap, not OOM-killed. Sizing a per-job cap (server-management#604) off memory.peak therefore inverts the decision: a big, mostly-file peak reads like "the cap must stay high" when it isn't. The OOM-forcing quantity is peak anon. The kernel exposes memory.peak but has no peak-anon counter, and the end-of-job anon is the composition then, not at the peak instant (a job that peaks mid-dotnet test then frees reports a misleadingly low anon) — so it must be sampled. Details + the sampler's robustness rationale: scripts/ci-peak-anon.sh header and docs/ci-cd.md → "CI build memory".

Implementation note (do not "simplify" back to memory.peak). The sampler is a detached nohup poller that survives step-boundary re-execs (reparents to the container's PID 1) and is reaped at container teardown; a TERM trap + sleep & wait stops it at once on report. Both steps are continue-on-error with a fail-open script, so the instrument can never redden a green build. Validated on bumblebee: it catches a transient 2.5 GiB anon spike that the end-of-job snapshot reports as 0.

Compiler-server A/B verdict (refines the #406 entry's "premise looking dead" read). Measured in the CI image, swap-off, sampled peak-anon, n=2 interleaved: OFF (the CI config) ≈ 5.84 GiB, consistent; ON (defaults) 6.3–7.6 GiB, always higher, + a ~3 GiB resident VBCSCompiler. Disabling the servers is worth it (consistent reduction, no resident server), but OFF sits right at 6 GiB for the build phase alone and the test job adds test + coverage on top — so #406's premise ("disabling brings peak well under 6 GiB → the budget loosens") is not supported. Size the cap off the live test-job peak-anon this instrument now reports, not off the build-only A/B. The older #411 probe (anon 7134 MiB) read higher than these swap-off sampled numbers and is superseded (swap/read-method move the figure >1 GiB).

2026-07-19 — Media-server remote-stream URLs are probed before use: a redirected 404 fails closed, everything else fails open, no toggle (#473)

key: media.remote-stream-probe · status: active · since: 2026-07-19 · supersedes: none · superseded-by: none Rule: ValidatePlayoutItemPath probes the Plex/Jellyfin/Emby remote-stream URL via IRemoteStreamProber before returning it; only a redirected 404 fails closed (PlayoutItemNotAvailableFromMediaServer), everything else fails open, and there is no toggle. Signals: remote-stream probing, fail-open/fail-closed, exit-8 ffmpeg loop · paths: GetPlayoutItemProcessByChannelNumberHandler.ValidatePlayoutItemPath, IRemoteStreamProber · issues: #473, #350, #480 Mechanics: HttpRemoteStreamProberTests (Should_Fail_Open_* / Should_Fail_Open_On_404_That_Was_Not_Redirected)

GetPlayoutItemProcessByChannelNumberHandler.ValidatePlayoutItemPath now probes the Plex/Jellyfin/Emby remote-stream URL via the new IRemoteStreamProber seam before returning it, and on a 404 from the media server returns the new PlayoutItemNotAvailableFromMediaServer error instead of a playable path.

• The bug this closes. The method's local branch checked _fileSystem.File.Exists(path), but the three remote-stream branches returned http://localhost:{port}/media/{plex,jellyfin,emby}/{id} unconditionally. When the media was gone from the media server too, validation "succeeded", ffmpeg was launched against a URL that 404s and died with exit 8 — landing in HlsSessionWorker's generic ffmpeg-failure path, which sizes its error card to the failed 44s work-ahead chunk and then re-selects the same broken item, so a dead item produces a repeating error card for its whole slot (~22 min for an episode). The fix restores the method's own invariant — every PlayoutItemWithPath it returns has been checked for existence — so the failure now returns an error rather than a playable URL, and the handler's error path sizes the card to run until the next playout item.
• What the new case label does and does not do (a review corrected an earlier draft of this entry): the skip-to-next-item sizing comes from maybeDuration/finish, computed before the switch — the default: arm already had it. Adding case PlayoutItemNotAvailableFromMediaServer: alongside PlayoutItemDoesNotExistOnDisk changes only the caption on the card (the real error text instead of "Channel is Offline"). Worth having, but not where the fix lives. A handler test asserts that message specifically, so the label cannot silently decay into dead weight.
• Scope: the generated-playout path only. All three remote branches of ValidatePlayoutItemPath are covered. ExternalJsonPlayoutItemProvider builds its own /media/plex/... URL and its result is assigned without passing through ValidatePlayoutItemPath, so external-JSON channels keep the old behaviour — tracked as #480 rather than silently claimed as fixed. The troubleshooting and subtitle-extraction paths build the same URLs and are deliberately left unprobed: troubleshooting should surface the raw ffmpeg failure, and a subtitle-extraction miss is not a channel outage.
• Fail-open on everything except a redirected 404. A timeout, a 5xx, an auth error or a transport failure returns available — and so does a 404 that arrived without a redirect. ErsatzTV's own InternalController returns NotFound when the media source is unconfigured or momentarily missing, so honouring that would fail closed for every item on that source; the first draft probed for "any 404", which made this contract untrue. Only a 404 reached after the redirect to the media server is evidence the item is gone. Pinned by tests (Should_Fail_Open_*, Should_Fail_Open_On_404_That_Was_Not_Redirected) so a later refactor can't quietly invert it. Caller cancellation is not swallowed — it propagates, because a shutdown is a genuine signal, not a probe failure.
• No ConfigElement toggle. The behaviour strictly dominates the status quo, and the probe is bounded by a 2s linked-CTS timeout (not HttpClient.Timeout, which defaults to 100s). A toggle would be surface for a switch nobody has a reason to flip. Not yet measured: on an install without path replacement every item selection pays this probe, and a slow media server could cost up to the full 2s. That is a worst case rather than a typical one, but it has not been measured against #350's cold-start budget — measure before assuming it is noise.
• Rejected — resizing the HlsSessionWorker retry loop to skip the item on any ffmpeg failure. It buys the viewer nothing the above doesn't (the slot is dead either way) and cannot distinguish "this item is dead" from "this transcoder hiccupped". Prod shows real transient channel-wide failures (VAAPI hwupload -22 / exit 234), and retrying those is correct; converting them into whole-item blackouts is a regression. The retry loop is deliberately left intact — it also remains the backstop for the probe's TOCTOU window (media can vanish between a 200 probe and ffmpeg's own request).
• Rejected — writing MediaItemState from the streaming path. Only the scanner writes State, and breaking that ownership wouldn't even have fixed this: the failing item is RemoteOnly, which PlayoutBuilder's PlayoutSkipMissingItems skip does not exclude. On Jellyfin (ServerSupportsRemoteStreaming) RemoteOnly is the normal state for every item when path replacement isn't configured, so it carries no signal about playability — never key availability decisions off it.
• Deferred — HEAD instead of GET. The probe sends GET with Range: bytes=0-0, which on /Videos/{id}/stream?static=true is a real (if minimal) playback request and may register a session or touch play-state on some media-server versions. GET was chosen because HEAD support varies across media servers — that is a reasonable prior but an unverified one. A HEAD-with-GET-fallback would avoid the side effect; deferred rather than guessed at, since it trades a known-working request for an untested one.

2026-07-19 — A media-server library sweep refuses to flag when a successful fetch returns zero items, rather than nuking the whole library (#477)

key: scan.zero-item-fetch-guard · status: active · since: 2026-07-19 · supersedes: none · superseded-by: none Rule: A media-server library sweep refuses to flag missing items when a successful fetch returns zero incoming items against a non-empty existing set (MediaServerReconciliationGuard.ShouldFlagMissing), rather than treating an ambiguous empty result as a full-library deletion. Signals: library sweep, zero-item guard, anti-nuke · paths: MediaServerReconciliationGuard, MediaServerTelevisionLibraryScanner/MovieLibraryScanner/OtherVideoLibraryScanner · issues: #477, #476 Mechanics: MediaServerReconciliationGuardTests policy table

Each media-server scanner reconciles "gone upstream" as existing.Except(incoming) and flags the result FileNotFound. If a successful fetch returns zero items — the server is up but mid-restore / mid-rebuild, or the library was genuinely emptied upstream — then existing.Except([]) is every item, so one scan flags the entire library. That is data-loss-adjacent: EmptyTrashHandler permanently deletes state:FileNotFound rows (a user clicking Empty Trash after a bad scan), and PlayoutSkipMissingItems empties every affected collection (dead channels). There was no zero-count / ratio / server-total guard; the only thing that stopped a mid-pagination failure was an exception unwinding past the flag step — protection by accident of control flow, not by design.

• The guard is a single shared policy. MediaServerReconciliationGuard.ShouldFlagMissing(logger, libraryName, incomingCount, existingCount) returns false (and logs a Warning) only when incomingCount == 0 && existingCount > 0; every other combination sweeps normally. Wired into the three library-level sweeps — MediaServerTelevisionLibraryScanner (shows), MediaServerMovieLibraryScanner, MediaServerOtherVideoLibraryScanner. One place owns the invariant so the policy can't drift between scanners.
• An empty incoming set is genuinely ambiguous, so we choose the non-destructive branch. "User removed every item" and "server returned empty erroneously" are indistinguishable at scan time — both report a total of zero (the paginator computes pages from TotalRecordCount, so a 0 total is a clean empty enumeration, not an error). Given the blast radius, skipping wins: the cost of not flagging a legitimately-emptied library (stale rows persist until an item returns or the library is removed by hand) is far smaller than a one-scan permanent wipe of a live library.
• This partially overrides #476 for the degenerate case, on purpose. #476 cascades a removed show's flag to its seasons/episodes. Its common path — some items removed while survivors are present (incoming non-empty) — still flags and cascades exactly as before. Only the degenerate "the last item was removed, so incoming is empty" case now skips instead of flagging. The #476 characterization test was rewritten from an empty incoming to a survivor-plus-removed partial deletion so it exercises the cascade without tripping the guard.
• Scope: library-level sweeps only; the nested TV season/episode sweeps are deliberately left unguarded. Their blast radius is one show's seasons / one season's episodes (not the whole library), a per-parent empty is a more plausible legitimate state there, and the #476 descendant cascade already handles a fully removed parent. Guarding them would alter #476's per-parent behaviour for little safety gain.
• Deferred — ratio threshold and projection-failure detection. The issue also floated "skip if the missing fraction exceeds a threshold" and "distinguish a silently-dropped projection failure from a real deletion." A ratio threshold risks suppressing a legitimate bulk deletion and needs a tunable, telemetry- backed policy; projection-failure detection needs a dropped-count threaded out of JellyfinApiClient through to the scanner (a cross-layer change). The deterministic zero-count guard has no false positives and covers the reported catastrophic case, so both are deferred to a follow-up rather than guessed at here.
• Tests. MediaServerReconciliationGuardTests pins the policy table (only (0, N>0) skips-and-warns; (0,0), (3,5), (3,0) all sweep). Per-scanner integration tests (MediaServer{Television,Movie,OtherVideo}LibraryScannerTests) prove the wiring: empty incoming + non-empty existing flags nothing and reindexes nothing. Proven non-vacuous by neutralizing the guard and watching all four anti-nuke assertions fail while the (0,0) no-op case stays green.

2026-07-20 — External-JSON playout channels now probe the remote-stream URL too, closing the #473 scope gap (#480)

key: media.remote-stream-probe-externaljson · status: active · since: 2026-07-20 · supersedes: none · superseded-by: none Rule: External-JSON playout channels' StreamRemotely now probes the remote-stream URL through the same IRemoteStreamProber seam as the generated-playout path, closing the #473 scope gap for a channel kind with no DB PlayoutItem rows. Signals: external-JSON channels, remote-stream probe, scope-gap follow-up · paths: ExternalJsonPlayoutItemProvider.StreamRemotely · issues: #480, #473 Mechanics: ExternalJsonPlayoutItemProviderTests

The #473 fix (PR #479, the entry above dated 2026-07-19) probed Plex/Jellyfin/Emby remote-stream URLs in GetPlayoutItemProcessByChannelNumberHandler.ValidatePlayoutItemPath, but explicitly scoped itself to the generated-playout path and flagged ExternalJsonPlayoutItemProvider as the surviving hole (tracked as #480). That provider builds its own /media/plex/{server}/{plexFile} URL in StreamRemotely and its result is assigned in the handler without passing through ValidatePlayoutItemPath, so for external-JSON channels a media item gone from the server still 404'd under ffmpeg (exit 8) and the same dead item was re-selected for its whole slot. This closes that gap.

• Fix location: the provider, not a new handler choke point. StreamRemotely now probes the URL via the same IRemoteStreamProber seam before returning it, mirroring the three generated-playout branches. The handler-side single-choke-point option (route every PlayoutItemWithPath through one validator) was rejected: the external-JSON provider constructs a synthetic MediaItem/PlayoutItem (from the JSON + Plex API) whose path is already a /media/plex/... URL, so it does not fit ValidatePlayoutItemPath's local-path-then-per-provider-switch derivation without contortion. Per-provider probing keeps the blast radius to one method; the fail-open policy (only a redirected 404 fails closed) lives entirely inside IRemoteStreamProber, so the second call site duplicates only the decision to probe, not the policy.
• Probe before the Plex metadata round-trip. The URL depends only on server.Id + program.PlexFile, not on the constructed MediaItem, so the probe runs before GetPlexEpisode/GetPlexMovie. A gone item therefore also skips the Plex API metadata call (which would otherwise throw NotSupportedException on a Left).
• Error type + card sizing. An unavailable stream returns PlayoutItemNotAvailableFromMediaServer, which the handler already maps (case added in #473) to a real-error card rather than "Channel is Offline". One behavioural difference from the generated path is accepted: external-JSON channels have no DB PlayoutItem rows (their schedule is a JSON file), so the handler's maybeNextStart query returns none and the error card falls to the existing 1-minute work-ahead clamp instead of spanning to the next item. The worker then re-tunes and advances by time. That is repeated 1-minute error cards within a long dead slot rather than one long card — strictly better than the exit-8 loop, and sizing to the next JSON program would require parsing the schedule here (deferred, out of scope).
• Tests. ExternalJsonPlayoutItemProviderTests pins both directions (unavailable → Left PlayoutItemNotAvailableFromMediaServer and no metadata call; available → Right with the /media/plex URL). The fail-open contract itself stays pinned by HttpRemoteStreamProberTests. Proven non-vacuous by neutralizing the probe guard and watching the unavailable assertion flip to Right.

2026-07-20 — ILibraryRepository.GetOrAddFolder resolves the folder from the DB, not the caller's LibraryPath.LibraryFolders navigation (#488)

key: scan.getoraddfolder-db-lookup · status: active · since: 2026-07-20 · supersedes: none · superseded-by: none Rule: ILibraryRepository.GetOrAddFolder resolves the existing folder via a DB query on (LibraryPathId, Path), not the caller's LibraryPath.LibraryFolders in-memory navigation, since that navigation is only eager-loaded on the local scan path and is null on remote (Jellyfin) callers. Signals: GetOrAddFolder, LibraryFolders navigation, ArgumentNullException, folder lookup contract, remote scanner crash, eager-load assumption · paths: ILibraryRepository.GetOrAddFolder, LibraryRepositoryTests, JellyfinMusicVideoLibraryScanner · issues: #488 Mechanics: LibraryRepositoryTests (LibraryPath.LibraryFolders == null case); test coverage in LibraryRepositoryTests

GetOrAddFolder looked the existing folder up by reading libraryPath.LibraryFolders in memory. That navigation collection is only eager-loaded on the local scan path — LibraryRepository.GetLibrary .Include(l => l.Paths).ThenInclude(p => p.LibraryFolders) — which every *FolderScanner goes through. The remote (Jellyfin) sync path takes its LibraryPath straight off the JellyfinLibrary entity, whose Paths[].LibraryFolders is null, so .Filter(...) on it hit Enumerable.Where(null, …) and threw ArgumentNullException('source') on the very first item of every Jellyfin music-video scan. JellyfinMusicVideoLibraryScanner is the only remote caller of GetOrAddFolder (it does not derive from the MediaServer*LibraryScanner base that the movie/TV/other-video remote scanners share), which is why no other remote scanner tripped it, and the feature had never run in prod, CI, or locally.

• Fix the repository, not the caller. The lookup now queries dbContext.LibraryFolders by (LibraryPathId, Path) (the method already opened a dbContext for the insert). This removes the implicit, undocumented loading contract entirely — correct for all nine callers — rather than the caller-side option (eager-load LibraryFolders on the Jellyfin path), which would have left the contract intact for the next remote scanner to trip. The contract change is now stated on ILibraryRepository.GetOrAddFolder.
• null ≠ empty — do not coerce. A null navigation meant unknown, not known-absent; treating it as an empty collection would fall through to CreateNewFolder and insert a duplicate LibraryFolder for a path that already exists (there is no unique constraint behind it). Querying the DB distinguishes the two.
• No new hot-path cost. Every local scanner already calls GetParentFolderId (a DB query with the same (LibraryPathId, …) shape) once per folder immediately before GetOrAddFolder, so the folder granularity was never served purely from memory; this adds one indexed lookup per folder, not a per-file query. As a bonus the DB lookup also sees folders created earlier in the same scan, which the load-time in-memory snapshot could not.
• Tests. LibraryRepositoryTests (real in-memory-SQLite TvContext) drives GetOrAddFolder with LibraryPath.LibraryFolders == null — the exact remote-path shape — and asserts it creates the folder and is idempotent on re-scan (no duplicate row). Proven non-vacuous by restoring the navigation-collection lookup and watching both tests fail with the issue's ArgumentNullException('source'). Note: CleanEtagsForLibraryPath still reads libraryPath.LibraryFolders directly, but it is only reached on the local (eager-loaded) path, so it is not affected; left as-is (out of #488 scope).

2026-07-20 — JellyfinMusicVideoLibraryScanner reconciles by library-scoped path diff + hard delete, not server itemId soft-trash (#494)

key: scan.musicvideo-reconciliation · status: active · since: 2026-07-20 · supersedes: none · superseded-by: none Rule: JellyfinMusicVideoLibraryScanner reconciles removed music videos by a library-scoped local-path diff plus hard delete (TrashMissingMusicVideos), not the server-itemId soft-trash pattern the other media-server scanners use, because music videos carry no server identity. Signals: music-video trash sweep, path-based identity, cross-kind safety, path-keyed identity, empty-fetch guard reuse · paths: JellyfinMusicVideoLibraryScanner.TrashMissingMusicVideos, FindMusicVideoPaths/DeleteByPath, IMusicVideoRepository, MediaServerReconciliationGuard · issues: #494, #477, #488, #496 Mechanics: ScanLibrary_Should_Not_CrossDelete_Movie_Or_Show_Sharing_The_LibraryPath; ScanLibrary_Should_Not_Sweep_When_Jellyfin_Returns_Zero_Items; integration tests extending the #488 harness

The Jellyfin music-video scanner did add/update only — a music video removed on the Jellyfin side lingered in ErsatzTV forever and could still be scheduled. It now runs a trash sweep at the end of ScanLibrary (TrashMissingMusicVideos), mirroring the MediaServer{Movie,Television,OtherVideo}LibraryScanner "gone upstream ⇒ remove" pattern but with a deliberately different identity function, because music videos lack the media-server identity those base scanners rely on.

• Identity is (LibraryPathId, path), not server itemId. The base scanners diff GetExisting* (keyed by MediaServerItemId) against the incoming server item ids, then soft-trash via FlagFileNotFound. Music videos have no JellyfinMusicVideo entity and no ItemId/Etag — the scanner is a standalone IJellyfinMusicVideoLibraryScanner that injects the local IMusicVideoRepository, which offers no itemId-keyed existing-set or flag seam. So the sweep diffs the local path set instead: existing = FindMusicVideoPaths(libraryPath) .Except the incoming items' replaced local paths, then hard-deletes the remainder with DeleteByPath + IScannerProxy.RemoveMediaItems, and cleans now-empty artists with IArtistRepository.DeleteEmptyArtists. Hard delete (not soft FileNotFound trash) because there is no per-item FileNotFound seam on this path and the issue's Done-when is "removed".
• Cross-kind safety is a property of the queries, not the media kind. MediaItem is TPT with LibraryPathId on the abstract base, so a Movie, Show and MusicVideo can share one LibraryPath (a mixed Jellyfin library). Both FindMusicVideoPaths and DeleteByPath filter LibraryPathId and join the concrete MusicVideo table, so the sweep can only ever see/delete music videos — a Movie/Show under the same LibraryPath is invisible to it. Pinned by ScanLibrary_Should_Not_CrossDelete_Movie_Or_Show_Sharing_The_LibraryPath.
• Reuses the #477 empty-fetch guard. The sweep is gated by MediaServerReconciliationGuard.ShouldFlagMissing — a successful fetch that returns zero items (server mid-restore / transient) is indistinguishable from a real emptying, so the whole-library wipe is refused and logged. Pinned as a negative control by ScanLibrary_Should_Not_Sweep_When_Jellyfin_Returns_Zero_Items (removing the guard flips it red).
• Known limitation (deferred to per-library identity). MusicVideoRepository.GetOrAdd dedups a path globally (no LibraryPathId predicate), so a file served by two libraries with overlapping local paths is a single row owned by whichever library scanned it first. If that owner later stops reporting the file while another library still serves it, this sweep removes the shared row. A proper fix needs per-library music-video identity (a JellyfinMusicVideo etag entity + migration) — the issue's "option 2 / fold into the base scanner" refactor — tracked as #496.
• Tests. Integration tests (real ArtistRepository/MusicVideoRepository/LibraryRepository over in-memory SQLite, extending the #488 harness) pin removal, empty-artist cleanup, cross-kind safety, and the empty-fetch guard. Proven non-vacuous: all four fail against the pre-fix scanner except the guard control, which only earns its keep once the sweep exists.

2026-07-20 (#489) — Jellyfin mixed-content libraries map to one library holding many kinds

key: scan.jellyfin-mixed-content-library · status: active · since: 2026-07-20 · supersedes: none · superseded-by: none Rule: A Jellyfin library whose collection type is mixed (or absent) maps to one ErsatzTV library of LibraryMediaKind.Mixed, scanned by running the movie/television/music-video scanners in sequence against that single library — a library is a place, not a media kind. Signals: mixed-content library, LibraryMediaKind.Mixed, per-kind sequential scan, per-kind scan dispatch, silent-success bug · paths: JellyfinApiClient.Project(), ScanMixedLibrary, SynchronizeJellyfinLibraryByIdHandler, ScanLocalLibraryHandler · issues: #489, #474, #488 Mechanics: local mixed libraries deliberately unsupported (LocalFolderScanner.VideoFileExtensions hazard); LibraryMediaKind.Mixed dispatch in the Jellyfin sync handlers; per-kind scanners queried by parentId + includeItemTypes

A Jellyfin library whose collection type is mixed — or absent — now maps to LibraryMediaKind.Mixed instead of being dropped by JellyfinApiClient.Project()'s _ => None. Scanning it runs the movie, television and music-video scanners in sequence against that one library.

• A library is a place, not a media kind. One physical path ↔ one Jellyfin library ↔ one ErsatzTV library, whose contents are heterogeneous. This is what keeps music and standup content segregated from the main Movies and TV Shows libraries, which was the actual goal (#474). The previous workaround was a local library pointed at the same tree, which bypassed Jellyfin, scanned the content twice and mis-modelled shows as movies.
• The classification is Jellyfin's, not ours. Each scanner queries parentId + includeItemTypes ("Movie" / "Series" / "MusicVideo"), so the three passes receive disjoint, authoritative sets. Nothing is inferred from folder shape or NFO contents. This is why mixed support is tractable at all — an earlier reading that it would require guessing per item was wrong.
• No migration. MediaItem is table-per-type with no discriminator and LibraryPathId on the abstract base, so heterogeneous items under one LibraryPath were always legal; MediaItemRepository.GetAllTrashedItems already COALESCEs across every subclass id for a single path.
• No cross-deletion. Reconciliation is type-scoped (GetExistingMovies(library) and friends), so a pass over one kind cannot trash another kind's items in the same library.
• MediaKind is dispatch + presentation only. Scheduling, playout, collections, smart collections and search hold zero references to it; search keys off the item's own subclass and the SPA's browse screens use a per-item LibraryBrowseMediaType. Adding a kind is therefore cheap.

Deliberately scoped to Jellyfin. Local mixed libraries are NOT supported and Mixed is absent from the SPA's local-library media-kind options. Locally the same approach is unsafe: every local scanner shares LocalFolderScanner.VideoFileExtensions, so the movie scanner would claim episode files, and LibraryFolder rows are keyed by LibraryPathId with no notion of kind, so two scanners over one path would thrash each other's etags. Neither hazard exists remotely — among the remote scanners only JellyfinMusicVideoLibraryScanner touches LibraryFolder at all. (The existing Images + OtherVideos shared-path exemption in LocalLibraryHandlerBase.AreSubPaths is the closest local analogue, and it already carries that etag contention.)

Failure semantics of the Mixed arm: one kind failing does not skip the others — a broken music-video scan must not prevent the movies in the same library from being ingested — but the library as a whole then reports failure and LastScan is not stamped. ScanCanceled aborts the sequence immediately, since a user cancellation is not one kind failing.

Also fixed here: ScanLocalLibraryHandler and SynchronizeJellyfinLibraryByIdHandler both ended their dispatch switch with _ => Unit.Default, returning success for an unhandled kind and stamping LastScan as though a scan had run. Both now return a BaseError. That silent success is precisely how a missing Mixed arm would have hidden, so removing it is part of the feature, not a drive-by.

Known limitations of the Mixed arm, surfaced by the adversarial review and accepted rather than fixed here:

• Scan progress resets twice. Each per-kind scanner independently drives _scannerProxy.UpdateProgress from 0 to 1 over its own item set, so a mixed library's progress bar fills and resets three times. The local scanner solves this by threading progressMin/progressMax per path (ScanLocalLibraryHandler), but the Jellyfin ScanLibrary signature has no such parameter, so fixing it means changing three scanner interfaces. Cosmetic, and deliberately out of scope.
• One permanently-failing kind forces the healthy kinds to rescan forever. ScanMixedLibrary returns Left if any arm failed, so LastScan is never stamped and the whole library re-scans every interval. Single-kind libraries already behave this way; Mixed widens the blast radius to the other two kinds. Accepted: the alternative — stamping LastScan on partial success — would silently mask a broken kind, which is worse.
• JellyfinMusicVideoLibraryScanner performs no reconciliation at all — no GetExisting*, no trash sweep. This is why it cannot cross-delete in a mixed library, but it also means a music video removed from Jellyfin is never removed from ErsatzTV. Pre-existing and orthogonal to this change; it belongs with that scanner's other gaps (no ItemId/Etag, path-keyed identity — see #488).

2026-07-20 — One logo drives the bug via a shared ChannelLogo preset, not new schema (#67)

key: iptv.logo-drives-bug-preset · status: active · since: 2026-07-20 · supersedes: none · superseded-by: none Rule: One uploaded channel logo drives both the listing logo and the on-screen bug via a shared, seeded ChannelLogo-sourced watermark preset (Channel Bug), not new per-channel schema. Signals: channel logo, watermark bug preset, ChannelWatermark seeding, ChannelLogo imageSource, seed/adopt semantics, quick-add · paths: ChannelWatermarkImageSource.ChannelLogo, DbInitializer.Initialize, watermark.channel_bug_seeded, WatermarkResponseModel · issues: #67, #286, #502 Mechanics: DbInitializerChannelBugWatermarkTests; WatermarkResponseModel.imageSource; DbInitializer seeded Channel Bug watermark + watermark.channel_bug_seeded ConfigElement marker

#67 asked that one uploaded image drive both the listing logo and the on-screen bug, separably overridable, with preview. Most of it already existed: ChannelWatermarkImageSource.ChannelLogo resolves the channel's own logo artwork at render time at all three watermark precedence levels, and Custom already provides the independent override. Production had already been running exactly this pattern by hand — 43 channels pointing at one hand-made Channel Bug preset.

Decision: seed that preset rather than add per-channel bug columns. A watermark is a shared named entity, so per-channel geometry would need either a dual-provider migration or one watermark row per channel (under a unique-name index). Since ChannelLogo resolves per channel at render time, a single shared row already delivers the user-visible behavior with no schema change.

• The seed adopts an existing Channel Bug row untouched, so an operator's tuned geometry is never overwritten, and a ConfigElement marker (watermark.channel_bug_seeded) makes it run once per database rather than once per name-absence — ChannelWatermark has no IsSystem flag and DbInitializer.Initialize runs at every startup, so a name-only guard would resurrect a deliberately deleted preset forever. Covered by DbInitializerChannelBugWatermarkTests.
• WatermarkResponseModel gained imageSource (additive under the frozen /api/v1, #286) so clients identify logo-driven presets generically instead of matching a user-editable name. Note the limit: once a second logo-driven preset exists, imageSource identifies the class but not the default, so findLogoBugWatermark prefers the seeded name as a deterministic tiebreak.
• The default is applied by the SPA's quick-add creation path, not by inferring "newness" in the editor — quick-add creates through the API and then navigates to the editor, so the editor only ever loads an existing row. The editor toggle reflects the referenced watermark's imageSource; an earlier draft searched the list instead, which (because getWatermarks() sorts by name) would have silently repointed channels bound to a non-first logo-driven preset. Caught in independent review and pinned by a regression test.
• The builder flow is covered on fresh installs only, by stamping the preset onto the system channel templates the seed itself creates; existing installs' templates are never mutated.
• Server-side create defaulting was rejected: making an omitted watermarkId mean "give me a watermark" would surprise machine clients of the frozen API. POST /api/v1/channels/auto-tune is therefore unchanged.
• Not fixed here: external-URL logos never render a bug (WatermarkSelector File.Exists-checks a URL). Pre-existing, lands in the FFmpeg render path, tracked as #502. This change only stops the preview from promising it.

Accepted trade-off: every channel on the shared preset shares one geometry; per-channel tweaks mean creating a second preset on the Watermarks screen.

2026-07-22 — Channel-level graphics-element attachment + seeded On Now/Next text element (#74)

key: graphics.channel-level-attachment · status: active · since: 2026-07-22 · supersedes: none · superseded-by: none Rule: A channel can attach GraphicsElements directly via a new ChannelGraphicsElement join table (a base layer under deco/playout-item elements), and a built-in text element (on-now-next.yml) is seeded once per database so the On Now/Next overlay works out of the box. Signals: ChannelGraphicsElement, Channel graphics attachment, GraphicsElementSelector base layer, on-now-next seeded element, GraphicsElementDefaults.OnNowNextFileName, builtIn discriminator · paths: ErsatzTV.Core/Domain/ChannelGraphicsElement.cs, ErsatzTV.Core/FFmpeg/GraphicsElementSelector.cs, ErsatzTV.Infrastructure/Streaming/Graphics/GraphicsElementSeeder.cs, ConfigElementKey.GraphicsOnNowNextSeeded, GraphicsElementResponseModel.BuiltIn · issues: #74

#74 asked for a transient "On Now / Next" text bug burned onto the transcoded stream at each program transition. The rendering and EPG-template-data infrastructure already existed (upstream graphics engine + our #502/#511 remote-image/graphics-engine work); the gap was that graphics elements had no channel-level attachment — only PlayoutItem/ProgramScheduleItem/BlockItem/ Deco joins existed — and there was no seeded/built-in graphics element, unlike watermarks.

Decision: add a 5th join table, ChannelGraphicsElement, rather than reuse the watermark FK. Watermarks and graphics elements are separate parallel systems; a channel already has exactly one WatermarkId, already spent on the #67 logo bug, and multi-line EPG text is a poor fit for the single-image watermark model. ChannelGraphicsElement is structurally identical to the existing four joins (composite key {ChannelId, GraphicsElementId}), added via a dual-provider migration (scripts/add-migration.sh Add_ChannelGraphicsElement).

• GraphicsElementSelector.SelectGraphicsElements appends channel-level elements at the final fall-through, alongside playoutItem.PlayoutItemGraphicsElements — a base layer. A deco in Merge mode composes with it; a deco in Override/Disable mode returns earlier and so suppresses it (decos are allowed to override channel defaults, a deliberate rule). One more suppression path: on a filler item, a deco whose graphics-elements section is not set to run during filler (UseGraphicsElementsDuringFiller false) clears the result and returns for Merge and Override alike, so the channel base layer is dropped there too. HttpLiveStreamingDirect continues to return empty (ErsatzTV isn't transcoding, so there is no frame pipeline to draw into).
• Seeded built-in element, mirroring the iptv.logo-drives-bug-preset (#67) pattern: GraphicsElementSeeder.SeedOnNowNext writes on-now-next.yml into the graphics-elements templates folder (only if the file is absent — operator edits are never clobbered) and ensures a GraphicsElement row exists for it, guarded by the graphics.on_now_next_seeded ConfigElement marker so it runs once per database, not once per file-absence (the same reasoning as #67: the seeder runs at every startup, so a name/file-only guard would resurrect a deliberately deleted preset).
• The API needed a way for the SPA to find the built-in element without a fragile name-match — the direct #67 lesson (WatermarkResponseModel.imageSource). GraphicsElementResponseModel gained a server-derived BuiltIn bool, computed by comparing the row's Path filename to GraphicsElementDefaults.OnNowNextFileName rather than trusting the element's editable Name.
• The channel editor's Branding-tab "Show On Now / Next overlay" switch follows the exact pattern of the existing logo-bug toggle: on adds the built-in element's id to graphicsElementIds, off removes it; disabled (with an explanatory caption) when the channel is HLS-Direct.

Accepted trade-off: all channels that enable the toggle share one seeded element's geometry/ content; per-channel customization means editing the shared YAML or attaching a different element (the join is general, not restricted to the seeded one).

2026-07-20 (#498) — QSV decode is split from QSV encode via a single QsvPreferNativeDecoder bool

key: ffmpeg.qsv-decode-encode-split · status: active · since: 2026-07-20 · supersedes: none · superseded-by: none Rule: QSV decode is decoupled from QSV encode via a single FFmpegProfile.QsvPreferNativeDecoder bool (default ON, Linux-only), so a QSV encode profile can decode with the more tolerant native VA-API decoder instead of the QSV decoder, mirroring Jellyfin's hybrid decode/encode toggle instead of a general decode-family enum. Signals: QSV, native VA-API decode, Dolby Vision passthrough, hybrid decode/encode, HDR tonemap fallback · paths: FFmpegProfile.QsvPreferNativeDecoder, QsvPipelineBuilder.SetTonemap, QsvPipelineBuilder · issues: #498, #505 Mechanics: docs/superpowers/specs/2026-07-20-qsv-native-decode-design.md; migration HasDefaultValue(true) on the nullable bool? column; QsvPipelineBuilder decoder-mode branch

FFmpegProfile.HardwareAcceleration picked one pipeline builder for both decode and encode, so an Intel QSV profile decoded with the QSV decoder — which is materially less tolerant of imperfect H.264 than FFmpeg's native VA-API decoder and cannot carry Dolby Vision metadata. Jellyfin, on identical hardware, avoids this by decoding with VA-API and encoding with QSV; that combination was not expressible in ErsatzTV. Full design: docs/superpowers/specs/2026-07-20-qsv-native-decode-design.md.

• Chosen: a single, QSV-scoped FFmpegProfile.QsvPreferNativeDecoder boolean, mirroring Jellyfin's "Prefer OS native DXVA or VA-API hardware decoders" checkbox exactly — Jellyfin itself deliberately collapses this to one default-on toggle rather than a decode-family picker, and copying the reference tool's granularity avoids over-building past a problem it has already solved.
• Default ON. Native VA-API decode is strictly more tolerant of imperfect streams than the QSV decoder wrapper, and Dolby Vision passthrough requires it — so the working configuration is the default for a reliability fix. Existing QSV profiles adopt the hybrid on upgrade via the migration's HasDefaultValue(true) (SQLite INTEGER/MySQL tinyint, nullable with DEFAULT 1 — the column is bool? so an explicit false persists, while NULL/absent reads as ON via != false; a non-nullable bool + store default would make EF silently drop a create-with-false), no opt-in required.
• Rejected: a general DecodeHardwareAcceleration enum column decoupling decode and encode hardware families entirely. More configurable than Jellyfin's own control, but nothing in the codebase or the reported failure needs that generality yet — FFmpegState already separates DecoderHardwareAccelerationMode / EncoderHardwareAccelerationMode internally (used today for the software-decode-plus-hardware-encode error-loop fallback), so the seam to grow into a real enum exists if a second asymmetric-decode case ever shows up on another hardware family. Deferred rather than built now, on YAGNI grounds.
• Contained to the QSV builder. The flag does not touch PipelineBuilderFactory's single-builder dispatch per profile, and does not repurpose the existing decode/encode-mode fields into a general cross-family selector — that repurposing is exactly the rejected enum option, just introduced through the back door.
• Accepted trade-off — HDR tonemapping runs in software on the native path. With native decode ON the decoder mode is Vaapi, so QsvPipelineBuilder.SetTonemap (which only selects TonemapQsvFilter for DecoderHardwareAccelerationMode == Qsv) falls to the software zscale/tonemap chain for HDR content. Output is correct but costs CPU on the realtime path. Accepted for now because software tonemap is correct-but-slower while an unvalidated GPU-tonemap graph could be worse (needs the Intel host to verify), and the escape hatch covers it: HDR-on-QSV users who don't need the tolerant decoder set the flag OFF to keep GPU tonemap. Optimizing the native path to tonemap_qsv is tracked in #505.
• Native decode is Linux-only. Guarded with !OperatingSystem.IsWindows() in the QSV builder — FFmpeg has no vaapi hwaccel on Windows (and Windows QSV capabilities are over-reported), so on Windows a QSV profile keeps QSV decode regardless of the flag.

2026-07-20 — runs-on: small means git-only; the two docker build jobs move to ubuntu-latest (server-management#639)

key: ci.small-lane-git-only · status: active · since: 2026-07-20 · supersedes: none · superseded-by: none Rule: runs-on: small is defined by what a job does (git-only), not its usual runtime; the two docker build jobs (docker-build.yml, ci-image.yml) move to ubuntu-latest because their worst-case memory, not median runtime, was pinning the small lane's per-slot cap. Signals: CI lane definition, per-job memory cap, small lane widening, memory cap vs capacity, act setup-phase hang, docker build placement · paths: .gitea/workflows/docker-build.yml, .gitea/workflows/ci-image.yml, runner config · issues: server-management#639, #406, #604, #574 Mechanics: sum-of-caps rule (#406/#604); second jazz runner at --cpu-shares=128; docs/ci-cd.md

• The small lane is defined by what a job does, not by how long it usually takes. Both jobs removed from it here were justified as small on a runtime argument that only held in the common case: docker-build.yml's build is a 1-second skip on PR runs (but a real image build on main/tags), and ci-image.yml's build was reasoned about as "docker-only, no toolchain needed — it builds the toolchain", which is true and yet describes the single heaviest job in the lane. The lane's per-job memory cap is set by its worst member, not its median, so both of these forced --memory=10g.
• That cap, not a capacity decision, is what pinned the lane at one slot. 10 GiB per slot on a 25 GiB host that also runs prod media permits exactly one — the sum-of-caps rule from #406/#604 (6 slots × 10 GiB on a 25 GiB host produced load 340 and 21 GiB of swap). So "widen the lane" and "keep the heavy jobs" were never simultaneously available; the earlier note in the runner config had parked the widening indefinitely behind moving the lane to a different host.
• Fixing the cap dominates fixing the capacity. With both builds on ubuntu-latest, small is a checkout plus a git diff, cappable at 1 GiB, so it widened from 1 slot to 4 across two hosts while committing less RAM to CI than the single slot did. A second runner was added on jazz at --cpu-shares=128 — CI on a prod media host is only acceptable while it loses every scheduling contest to the transcoders.
• The symptom this fixes is not queue wait. A saturated lane also wedges dispatched jobs in act's setup phase: >10 min in_progress, no log file written at all, then failure, before Checkout runs. That produced the standing "decisions.md is a known flake, just rerun it" belief — the rerun works only because it lands after load clears, so a capacity problem read as a bug in the guard. A job that fails with zero log output is evidence about the runner, not about the job.
• #574's skip-task queueing does not return by moving build back to ubuntu-latest: needs: [test, migrations] means it cannot be dispatched until the jobs it would have queued behind have already finished.

2026-07-20 — External-URL channel logos pass through to the graphics engine; never File.Exists-gated, never ffmpeg-native (#502)

key: ffmpeg.external-logo-graphics-engine · status: active · since: 2026-07-20 · supersedes: none · superseded-by: none Rule: External-URL channel logos pass through to the graphics engine like any other watermark source; WatermarkSelector must never gate them on File.Exists (always false for a URL) and never route them through the ffmpeg-native overlay shortcut. Signals: external-URL logo, WatermarkSelector, graphics engine · paths: WatermarkSelector, FFmpegLibraryProcessService, ImageElementBase.LoadImage · issues: #502, #67, #1, #510, #511 Mechanics: WatermarkSelectorChannelLogoTests; ChannelLogoWatermarkOptions helper

A channel whose logo is an external URL never rendered an on-screen bug, even with a ImageSource = ChannelLogo watermark attached. WatermarkSelector resolved the URL correctly and then existence-checked it on the filesystem — File.Exists("https://…") is always false — so all three precedence levels (playout item, channel, global) logged "Channel logo no longer exists" and returned None. The channel editor advertises the URL as winning over an uploaded logo, which is true for the guide listing and was silently false for the bug.

External artwork passes through; it is not downloaded into the image cache. That is already the codebase-wide convention — ChannelPlaylist (M3U), the XMLTV template data and Channels/Mapper (SPA JSON) all emit the raw URL and let the client fetch it. No fetch→SaveArtworkToCache glue exists anywhere, and adding it here would have invented a second convention for one consumer. The render path needs no such glue: ImageElementBase.LoadImage already detects an http(s) path, fetches it with HttpClient, and decodes it with ImageSharp for real pixel dimensions.

A remote-URL watermark is therefore forced onto the graphics engine, not the ffmpeg-native path. FFmpegLibraryProcessService normally shortcuts a single permanent watermark into a WatermarkInputFile handed to ffmpeg as a bare -i argument (and to ffprobe for animation detection). ffmpeg would likely open an http URL itself, but that puts an unbounded network fetch inside stream startup, with no timeout, redirect or auth handling under our control, and with dimensions left as a FrameSize(1, 1) placeholder. The graphics engine is the path actually built for remote images, so the shortcut now additionally requires a non-URL path.

Scope held deliberately narrow — two adjacent defects were left alone:

• The generated-initials fallback (no logo artwork ⇒ ChannelLogoGenerator.GenerateChannelLogoUrl, which hardcodes localhost, issue #1) is also killed by the same File.Exists. Reviving it is deferred by an earlier entry in this file, so it stays ignored — now behind an explicit comment and a scope-guard test rather than as an accident of the existence check.
• The deco path (OptionsForWatermarks → the private GetWatermarkOptions) has always returned its resolved path unchecked, so #502's File.Exists defect never reached it and its resolution is unchanged. Aligning its missing-file and no-artwork behavior with the three precedence levels is a behavior change in its own right, tracked as #510.

The routing change is NOT scoped that way, deliberately. CanUseFFmpegNativeWatermark keys off the resolved WatermarkOptions.ImagePath alone, and SelectWatermarks puts deco-derived options into the same list — so a deco watermark resolving to a URL is rerouted to the graphics engine too, including the generated-initials http://localhost:…/iptv/logos/gen URL that the deco path does still pass through. Routing by provenance instead of by what the path actually is would mean deciding the same thing twice and letting the two drift; the URL-aware path is the right one for any URL. Worth knowing when picking up #510: that fallback plausibly rendered through ffmpeg before and now composites through ImageSharp, which this change's live-E2E did not cover.

Accepted cost asymmetry. Graphics-engine compositing is per-frame ImageSharp work rather than ffmpeg's overlay filter, so two channels with visually identical bugs now transcode at different cost based only on whether the logo is a URL. The rejected fetch-once-into-the-image-cache alternative would have avoided that; if #511 (remote-fetch hardening: timeout, size cap, pooling, caching) adds such a cache, this goes with it.

The three gated levels now share one ChannelLogoWatermarkOptions helper so they cannot drift apart again — the duplication is what let the defect exist in triplicate. Covered by WatermarkSelectorChannelLogoTests, which pins the external-URL fix, both preserved regressions (cached local path, missing local file ignored) and the generated-fallback scope guard.

2026-07-20 — HLS cold start is fixed with -readrate_initial_burst, not by raising the work-ahead limit (#350)

key: ffmpeg.hls-cold-start-burst · status: active · since: 2026-07-20 · supersedes: none · superseded-by: none Rule: HLS cold-start latency is fixed with a bounded -readrate_initial_burst (gated on FFmpeg ≥6.1 capability detection), not by raising work_ahead_limit, which would remove the concurrency guarantee it exists for. Signals: HLS cold start, readrate, work_ahead_limit, HlsSessionWorker, FFmpegKnownOption capability gate · paths: HlsSessionWorker, SetRealtimeInput, FFmpegPlaybackSettingsCalculator, FFmpegKnownOption/HasOption · issues: #350 Mechanics: SetRealtimeInput readrate-burst option; FFmpegKnownOption.HasOption version-capability gate

Correction (2026-07-21, #529): the claim below that the burst is "bounded" is true only in seconds of input — it is not a bound on memory or hardware surfaces. -readrate was also incidentally bounding how fast decoded frames enter the filter graph, and removing that on a QSV pipeline whose profile stores qsvExtraHardwareFrames: 0 exhausts the upload pool: the graph fails with -12 (Cannot allocate memory), h264_qsv never opens, and zero segments are written. The burst is not the root cause (a work-ahead start takes no -readrate at all and was already failing the same way in production), but it removed the throttle on every realtime session and so made the failure near-deterministic. See ffmpeg.qsv-extra-hw-frames-floor; the decision recorded here still stands, with that floor in place.

Correction (2026-07-21, #536): the bullet below stating that "every concurrent tune-in falls back to the throttled path" described the intent, not the behaviour. The slot check and its increment straddled an await, so N simultaneous tune-ins all read 0 < limit and all started unthrottled; the "one winner, two throttled" observation held only because those tunes were effectively staggered. The measurement and the conclusions drawn from it stand — slot availability was the variable behind the bimodality — but the guarantee itself was not enforced until ffmpeg.work-ahead-slot-atomic.

• -readrate throttles from the first read, so it sets a floor on time-to-first-segment. The realtime playback path pins input reading to 1.05× wall clock so a channel behaves like live TV. Since OutputFormatHls.SegmentSeconds is 4 and the segmenter serves the playlist only once the first segment exists, the playlist cannot appear sooner than ~4/1.05 ≈ 3.8 s. Measured on real media: time-to-first-playlist 5369/5344 ms with -readrate 1.05, 648/649 ms with an initial burst.
• The cold-start bimodality was never about the media. HlsSessionWorker grants an unthrottled SeekAndWorkAhead start only while _workAheadCount < ffmpeg.segmenter.work_ahead_limit (prod: 1); every concurrent tune-in falls back to the throttled path. Three concurrent tunes on prod: the one that won the slot reached firstGop in 866 ms, the other two in 3845 ms and 6357 ms. This is why the earlier rounds found no correlation with subtitle burn-in, GOP length, or source file — the variable was slot availability, and the same channel could differ 7.2× between tunes.
• Two earlier hypotheses are falsified, not deferred. Accurate-seek decode-discard (the issue's ranked #1 driver) costs 30–100 ms on real prod media, and capping -probesize/-analyzeduration buys 20–50 ms. Neither can account for seconds. Recorded here so they are not re-proposed.
• Burst rather than a bigger work-ahead budget. Raising work_ahead_limit would fix latency by deleting the guarantee that limit exists for — it caps how many unthrottled transcodes N viewers can start at once. The burst is bounded (SegmentSeconds * 2 = 8 s of input, enough for the first segments at the default InitialSegmentCount of 1), after which live pacing resumes. An operator who raises InitialSegmentCount above 2 gets less of the benefit; that is a deliberate trade.
• The burst is per ffmpeg process — i.e. per playout item — not per session. SetRealtimeInput runs on every pipeline build and HlsSessionWorker spawns a process per item, so each item boundary bursts too; this is not only the session's cold start. Two consequences, both accepted: item transitions get the same head start (a benefit), and on a channel whose items are shorter than the burst every item transcodes unthrottled, so the instantaneous-concurrency guarantee that work_ahead_limit provides is weaker than before — weaker, not absent, because HlsSessionWorker's transcodedBuffer <= 1min gate still stops the loop at a 60 s buffer, leaving average CPU unchanged. Making the burst strictly cold-start-only would mean plumbing a "first process of this session" flag through FFmpegState; that complexity was not judged worth a bounded peak.
• Still images are excluded. Their video input is paced by the realtime filter and takes no readrate at all, so a burst would only run the audio input ahead of the video for songs and offline filler, with no cold-start gain to show for it.
• Non-HLS realtime outputs (TransportStream, HLS-Direct) burst too, since FFmpegPlaybackSettingsCalculator makes them unconditionally realtime. That is untested by the benchmark, which was segmenter-only; it is kept because the same first-read throttle delays those clients identically, and the outer WrapSegmenter/Concat processes still pace at readrate 1.0 with no burst.
• Gated on runtime capability, not on a parsed version. -readrate_initial_burst needs FFmpeg ≥ 6.1, and FFmpegKnownOption/HasOption already existed for exactly this (its AllOptions list had simply been empty). Detection parses ffmpeg -h long, so an older binary silently keeps today's behavior instead of failing to start — the same fail-safe posture as the other capability gates, and cheaper to reason about than the version-string parsing in NvidiaHardwareCapabilities.

2026-07-20 — MCP server (ErsatzTV.Mcp) built fresh over frozen /api/v1: read + cautious writes (#58)

key: mcp.server-foundation · status: active · since: 2026-07-20 · supersedes: none · superseded-by: none Rule: ErsatzTV.Mcp is a fresh stdio JSON-RPC server wrapping frozen /api/v1 with explicit narrow per-endpoint tools, read-only-by-default enforced at runtime (ERSATZTV_ALLOW_WRITES), machine-key auth, and opt-in If-Match. Signals: MCP server, tool catalog, read-only default, ERSATZTV_ALLOW_WRITES, X-Api-Key, If-Match round-trip · paths: ErsatzTV.Mcp, docs/mcp.md · issues: #58, #286, #197, #76, #289, #63, #64, #65, #66, #67, #68 Mechanics: docs/mcp.md; ErsatzTV.Mcp tool executor and catalog

The MCP server (issue #58, gated on #286 route-freeze + #197 security review, both closed) is built fresh as ErsatzTV.Mcp — a stdio JSON-RPC server wrapping /api/v1 — superseding the closed read-only PR #76 rather than rebasing it. Full doc: docs/mcp.md. Decisions frozen:

• Explicit, narrow tools over a generic HTTP passthrough. Each tool maps to one OpenAPI-backed endpoint; there is no "call any URL" tool. Each declared argument routes to exactly one place — path {param}, an explicit query parameter, the reserved ifMatch header, or (write verbs only) the JSON body — and additionalProperties:false rejects anything undeclared before a request is built.
• Read-only is the default, enforced at runtime, not just by catalog shape. The executor refuses any non-GET tool unless ERSATZTV_ALLOW_WRITES=true, so one wrong catalog entry cannot mutate. This is the PR #76/#289 posture carried forward verbatim, alongside the JSON-RPC DoS guards (-32700/-32600/-32602/-32603, bounded stdin line reader), the per-request CTS covering headers and the streamed body (the ResponseHeadersRead gotcha, #289), the response-size cap, and the reverse-proxy prefix preservation.
• Machine-key auth, CSRF-exempt. The server sends X-Api-Key on every request and no X-CSRF header (§9: key-authed requests are CSRF-exempt). ERSATZTV_API_KEY is effectively required.
• If-Match is opt-in per call, and ETags are surfaced, not managed. Only the replace-all PUTs honor If-Match (here update_collection_custom_order); a response ETag header is appended to the tool result as [etag: "N"] so an agent can round-trip it. All other writes force-write (§7a), so no ETag handshake is needed — notably add_collection_items, whose re-add is an idempotent no-op.
• Channel create/update is exposed (28-field DTO): only name/number/ffmpegProfileId are required, enums take the enum name and are API-validated, and get_channel makes the shape/current values discoverable. Deferred as too-large for a cautious v0.1 (not a contract gap): the ~40-field schedule-item / playout replace-list writes. Redesign workflow tools (#63–#68) stay deferred until their backend endpoints exist. No /api endpoint was added, so no OpenAPI regen.

2026-07-20 — Remote graphics-engine images are fetched through a bounded, pooled IRemoteImageFetcher; re-fetched per element init, not cached (#511)

key: ffmpeg.remote-image-fetcher-bounded · status: active · since: 2026-07-20 · supersedes: none · superseded-by: none Rule: remote graphics-engine images are fetched through IRemoteImageFetcher with a pooled HttpClientFactory client, a body-covering deadline, a wire-transfer size cap, and a decoder-enforced DecoderOptions.MaxFrames bound re-verified post-decode — never cached, re-fetched per element init. Signals: remote image fetch, decompression bomb, MaxFrames, decode budget vs retention budget, SSRF accepted risk · paths: IRemoteImageFetcher, HttpRemoteImageFetcher, ImageElementBase.LoadImage, DecoderOptions.MaxFrames, WatermarkElementRemoteImageTests · issues: #511, #502, #289 Mechanics: HttpRemoteImageFetcher (Infrastructure) over IHttpClientFactory; EnsureDecodeAffordable/EnsureScaledFramesAffordable pure-function budget checks

ImageElementBase.LoadImage fetched http(s) images with a throwaway new HttpClient() and GetStreamAsync. That is unbounded in three directions at once — no timeout override (the 100s HttpClient default), no response size cap, and a new connection pool per element — and it runs inside stream startup, while ffmpeg waits on the pipe. #502 routed ordinary channel-logo watermarks onto that path, which is what made a pre-existing weakness worth hardening.

The fetch now lives behind IRemoteImageFetcher (HttpRemoteImageFetcher), deliberately modelled on the neighbouring IRemoteStreamProber: a Core interface, an Infrastructure implementation over IHttpClientFactory, and a CancellationTokenSource.CreateLinkedTokenSource + CancelAfter deadline.

The deadline covers the body, not just the headers. The named client is registered with Timeout = InfiniteTimeSpan and the linked token is threaded into GetAsync and every stream read, because under HttpCompletionOption.ResponseHeadersRead the body read falls outside HttpClient.Timeout — a slow-drip host would otherwise hang forever. Same mechanic as #289.

The size cap is enforced during the copy, not from Content-Length. The advertised length is only a cheap early reject; it can be absent or a lie, so the byte counter in the copy loop is what actually bounds transfer and buffering. (It bounds the wire, not the decode — see below.) Both paths are covered by tests, and both were negative-controlled (disabling the checks fails exactly those two tests).

The byte cap does not bound decoding, so there are two further budgets — and the decode bound is imposed on the DECODER, not read from the header. A decompression bomb is by definition small on the wire: a 4 KB PNG can declare 30000x30000 (~3.6 GB to decode), and a 60 KiB GIF can declare 2500x2500 across 600 frames (~14 GiB). All of that passes Content-Length, the content-type check and the 10 MiB copy cap in milliseconds.

Getting this right took three attempts, and the two failures are the interesting part:

1. The first version checked dimensions (50 MP) and frame count (600) independently. The 2500x2500 x600 GIF above passes both while costing ~14 GiB. Independent caps do not compose into a budget — the bound has to be on the PRODUCT.
2. The second version checked the product, but sourced the frame count from Image.IdentifyAsync. Measured on ImageSharp 3.1.12: an APNG reports FrameMetadataCollection.Count == 0 while the decoder produces every frame. A 4000x4000 x600 APNG is ~134 KiB on the wire, is charged as ONE frame (16 MP, comfortably inside the budget) and decodes to ~36 GiB — 2.5x worse than the bomb that version was written to stop. Header-derived limits are advisory; a limit the decoder does not enforce is not a limit. (GIF, WebP and TIFF report honestly; PNG/APNG is the sole divergence, which is exactly why trusting the header is untenable — you cannot audit every format.)

So DecodeRemoteImage now: checks the header dimensions (which are trustworthy — a GIF whose image descriptor exceeds its logical screen is clamped by the decoder, verified); derives how many frames of that size the budget affords; passes that to DecoderOptions.MaxFrames, which the decoder enforces regardless of what the header claimed; and then re-verifies the real image.Frames.Count after decoding, disposing and rejecting if it is over. MaxFrames was measured as honored by every animated decoder in play (APNG, GIF, WebP, TIFF), which is what makes it a real bound rather than another advisory one. The code asks for affordable + 2 so an animation exactly at the limit still decodes in full while anything over it is visible to the post-decode check; the slop is at most two frames, since MaxFrames = N yields N frames for GIF/WebP/TIFF but N-1 for APNG — the exact count varies by format, so only the upper bound is relied on.

• Decode budget — width x height x frames <= 50 MP, verified against the decoded image.
• Retention budget — frames x scaledWidth x scaledHeight <= 200 MP (~800 MB at 4 bytes/px), checked once the scale is known. Independent of the decode budget in both directions: a 100x100 source is trivial to decode but retains ~5 GB of SKBitmap at 600 frames scaled to 1920x1080, because LoadImage clones and resizes every frame to output resolution and keeps them.

The enforced peak is up to 3x the nominal decode budget, and that is deliberate. Detecting "over the limit" requires actually decoding more frames than the limit allows, so the ceiling is (affordable + 2) x perFrame. In the pathological case — one frame that alone fills the budget, so affordable = 1 — that is 150 MP (~600 MB at Rgba32, ~1.2 GB for a 16-bit TIFF at Rgba64) rather than 50 MP. Bounded and survivable, against the ~36 GiB it replaces, and the alternative (tightening the single-frame allowance to budget/3) would reject legitimate 8K stills at 33 MP. Stated here because the previous three versions of this entry each claimed a bound the code did not actually enforce.

Other caveats: the budgets are in pixels, but a 16-bit PNG decodes to Rgba64 (8 B/px), so the byte cost doubles; the retention budget is per element, with no global ceiling across concurrent streams; and 200 MP caps a full-frame 1080p animated overlay at ~96 frames (~3.2s at 30fps), which is the one limit here that could plausibly bite a legitimate user rather than an attacker.

A workaround rides along with the header pre-pass. Image.IdentifyAsync is called with MaxFrames = 1 — not as a limit, but because a default Identify throws InvalidImageContentException on most APNGs (measured: 13 of 16 shapes, including files ImageSharp's own PngEncoder wrote) that Image.Load reads back perfectly. Adding the pre-pass without it would have silently disabled every animated-PNG logo that worked before this change — a functional regression introduced by a hardening change, caught only because the reviewer swept shapes rather than trusting the one the tests happened to use.

Both budgets are enforced by pure functions (EnsureDecodeAffordable, EnsureScaledFramesAffordable) so the arithmetic is tested at every boundary without materializing multi-gigabyte images, and both call sites have wiring coverage (deleting either one fails a test). The APNG case is pinned by a regression test that asserts the header under-reports and that the decode is rejected anyway. Local images are deliberately exempt: those are files an operator put on disk, not bytes an arbitrary host returned.

Content type is checked permissively. A positively-not-an-image type (an HTML error page) is rejected before the decoder sees it, but a missing type and application/octet-stream are allowed — hosts omit the header and static file servers default to octet-stream often enough that strictness would break working logos, while buying little: ImageSharp decodes by magic bytes, so the size and dimension caps are what actually protect the decoder.

Redirects stay enabled but capped at 3 (the default is 50). Logo hosts and CDNs legitimately redirect, so disabling them would break real configurations.

Not cached — re-fetched on each element initialization, i.e. per playout item. #502's entry noted that a fetch-once-into-the-image-cache design would also erase its per-frame cost asymmetry, so caching was considered here and rejected for now: with pooling, a 10s ceiling and a 10 MiB cap, one small GET per item transition is not a cost worth a cache's invalidation policy (when does an admin's logo change take effect?) and lifetime questions. It also keeps the codebase-wide "external artwork passes through, it is not downloaded into the image cache" convention #502 established intact. Revisit only with a measurement showing the re-fetch actually costs something.

SSRF is accepted, not mitigated. ChannelValidations.ValidateLogo still only checks the scheme, so an admin-set logo URL remains a request origin inside the container's network, and the redirect cap bounds hop count, not destination — an approved host can still redirect hop three to 169.254.169.254 or 127.0.0.1:<port>. This is deliberate, and the load-bearing reason is that the primitive is blind: the response body is never returned to any user, only decoded and composited into a video frame, and failures surface only as a log line. Combined with the capability being admin-only — and with LAN-hosted logos being a legitimate, common setup here, so a private-IP denylist would break working installs — the exposure does not justify the breakage. Revisit if logo URLs ever become settable through a lower-privilege path, or if any fetch result becomes readable by a caller; note that "admin-only" is the weaker half of this argument and blindness is the stronger.

Failures are surfaced as exceptions rather than a failure value, because both call sites (WatermarkElement, ImageElement) already wrap initialization in a catch that sets IsFinished — so a dead, slow or oversized URL degrades to "element disabled" and never kills the stream. WatermarkElementRemoteImageTests pins that contract, including that a local path never touches the fetcher.

The fetcher distinguishes its own deadline (rethrown as TimeoutException) from caller cancellation (propagated as OperationCanceledException) via an exception filter on cancellationToken.IsCancellationRequested. Be aware this distinction is currently observationally inert: the elements' pre-existing blanket catch (Exception) swallows both one frame up, so a shutdown mid-tune logs a spurious per-element warning. The filter is kept because it makes the fetcher correct on its own terms and the log message names the real cause; making the elements re-throw cancellation is a separate, pre-existing concern.

2026-07-21 — Decision records carry a lifecycle schema, validated by a script; append-only-by-diff is retired (#521)

key: docs.decision-lifecycle · status: active · since: 2026-07-21 · supersedes: docs.append-only-guard@2026-07-12 · superseded-by: none Rule: every decision ## record (active or archived) carries a 5-field metadata block (key, status, since, supersedes, superseded-by) checked by scripts/decisions_validate.py; a record is never deleted or line-edited to reverse a call — it is moved to docs/decisions/archive/ with status: superseded/retired and a reciprocal superseded-by/supersedes key pair to its replacement. Signals: decision lifecycle, supersession, archive · paths: scripts/decisions_lib.py, scripts/decisions_validate.py, scripts/build_decisions_catalog.py, docs/decisions/archive/ · issues: #520, #521 Mechanics: scripts/decisions_validate.py (PYTHONPATH=. python3 scripts/decisions_validate.py); catalog regen scripts/build_decisions_catalog.py; docs/decisions/migration-map.md

This replaces docs.append-only-guard (ersatztv#303 H9), not just extends it. The old guard treated docs/decisions.md as a single append-only text file: any line-delete was blocked by a Husky commit-msg hook + CI job, and a "supersession" was a hand-written > **Superseded …** banner prepended to the old entry plus an (superseded) Index tag — prose conventions an agent had to remember and apply correctly by hand, with no machine check that the banner, the tag, and the new entry's back-reference actually agreed with each other. That is exactly the failure mode this arc (#520/#521) set out to fix: state should be derived and checked, not asserted in prose (the same throughline as #303 H6's ## Done-when).

The new model. Every decision record — whether still in force or not — gets a key (dotted, stable identity independent of its heading text or which file it lives in), a status (active/superseded/retired/legacy-unmigrated for anything not yet carrying the schema), a since date, and a reciprocal supersedes/superseded-by pair of keys. scripts/decisions_lib.py parses the schema; scripts/decisions_validate.py enforces: at most one active record per key; superseded/retired records MUST live under docs/decisions/archive/, never in an active file; an active record MUST NOT live under archive/; every supersedes/superseded-by key must resolve to a record that actually exists (active or archived); and — replacing the append-only guard's line-delete detection — a record's rationale prose (the schema strips only the contiguous metadata block before comparing) must not change between a PR's base and head unless the commit carries [decisions-edit], and a record that disappears from the active set without a matching archive copy is flagged as an unlogged removal. scripts/build_decisions_catalog.py regenerates docs/decisions/README.md, a compact router listing only active records by key, so an agent doesn't have to read the full chronological log (or the archive) to find the current rule.

Why this is a strictly better enforcement of the same spirit, not a loosening. The old guard's actual invariant was never "no line may change" — it was "history is never silently rewritten to erase why we changed our mind." A hand-prepended banner satisfied that invariant by convention; a validator that checks reciprocal keys, archive placement, and rationale-prose stability satisfies it by construction, and additionally catches classes of mistake the old guard could not (a supersession banner added without moving the entry out of the active read-path; a superseded-by reference to a key that doesn't exist; two active records quietly claiming the same key after a copy-paste). [decisions-edit] is kept, narrowed to its one remaining legitimate use — an actual rationale-prose edit (fixing a factual error) — since routine lifecycle moves (a status flip, an archive relocation) are now token-free and machine-checked instead.

This PR is the first to exercise the new regime, on itself. docs.append-only-guard (the H9 half of #303's combined H9/H3 entry; H3's root-screenshot guard is untouched and stays active) is marked status: superseded and relocated to docs/decisions/archive/release-ci-governance.md, with this record as its superseded-by and this record's supersedes pointing back — the same-PR supersession pattern the new rule itself mandates for every future reversal. docs/decisions/migration-map.md tracks the legacy-heading → key → status → location mapping as the rest of the log migrates (ersatztv#520/#521, ongoing — most existing headings remain legacy-unmigrated until touched).

2026-07-21 — Parallel orientation + selection is the startup protocol; #237 retired (#520)

key: startup.parallel-orientation · status: active · since: 2026-07-21 · supersedes: docs.queue-state-gitea-tracker@2026-07-11 · superseded-by: none Rule: A fresh session runs two concurrent tracks at startup — Orientation (AGENTS.md/CLAUDE.md → docs/README.md task-signal map → the active decisions catalog docs/decisions/README.md) and, only when no issue is named, Selection (scripts/select-queue.sh N, deterministic live-Gitea ranking). A named issue skips Selection entirely. ersatztv#237, the closed pickup tracker this replaces, is reduced to a single archival breadcrumb and MUST NOT be read for live state. Signals: startup protocol, queue selection, MemPalace retrieval, breadcrumb rule · paths: docs/handoffs/chicorytv-issue-queue.md, scripts/select-queue.sh, docs/README.md, scripts/check-kickoff-guard.sh · issues: #237, #520, #521, server-management#642 Mechanics: docs/handoffs/chicorytv-issue-queue.md → "Two concurrent tracks at session start" + "Knowledge retrieval"; scripts/select-queue.sh; regression guard scripts/check-kickoff-guard.sh (wired into the decisions lifecycle CI job)

Why this reverses docs.queue-state-gitea-tracker (2026-07-11), not just extends it. That record's rule was "queue state lives in pinned tracker #237, not in the handoff file" — sound in 2026-07-11 when the arc was live and #237's body/comments were the only concurrency-safe place to put session state. Two things changed: (1) scripts/select-queue.sh (2026-07-19) already replaced the mechanical selection logic with a deterministic query over live Gitea state — no script reads #237's prose; and (2) the arc itself completed and #237 closed on 2026-07-13. A closed issue cannot be "where live queue state lives" — continuing to point agents at it was no longer just stale, it was actively wrong, and the old record's own text ("Pinned tracker issue #237 holds the goal + ordered arc") was live regression bait: a session reading it verbatim would try to treat a closed tracker as authoritative. So this is a genuine reversal (the store changes from "a specific Gitea issue" to "live Gitea queries, no pinned issue required"), not a mechanical follow-on.

What the new protocol is. Session start runs two independent tracks, neither blocking the other: Orientation — read AGENTS.md/CLAUDE.md, then docs/README.md's task-signal map (replacing the old mandatory 1–10 reading order), then the active decisions catalog docs/decisions/README.md for "why do we do X" questions. Selection — only when the user hasn't named an issue, run scripts/select-queue.sh [N], which excludes in-progress/parked/PRs, resolves GET /issues/{n}/dependencies, tiers by LOCAL .milestone.state/review/priority: filters, and orders deterministically; it flags CLAIM?/UMBRELLA? for the orchestrator to resolve by reading the flagged issue, and does not rank an arc tier (none is active in maintenance/backlog mode — if one is ever re-established, extend the script, never revert to prose-derived ranking). A user-named issue skips Selection outright and goes straight to focused retrieval on that issue.

MemPalace retrieval contract (server-management#642, the sole Gitea→MemPalace exporter). MemPalace is candidate discovery only, verified against its cited source before use, at a default ErsatzTV-Decisions wing; the four load-bearing orientation bullets — catalog-first for current rules, issue history as evidence not authority, the breadcrumb rule (a file path in a historical comment resolves by concept via the active wing, never by literal path-chase), and the catalog→rg exact-search fallback when MemPalace is stale/down — are carried verbatim in docs/README.md and docs/handoffs/chicorytv-issue-queue.md. Never derive live queue state from MemPalace, #237, or historical comments; live Gitea state via scripts/select-queue.sh is the only source of truth for pickup ordering. The ## Closing record template (Outcome / Root cause / Decisions changed / Reusable knowledge / Verification / Deferred / Docs updated) is the structured per-issue artifact this retrieval contract is built to consume — see CLAUDE.md → Task Completion Protocol and the kickoff's "Closing record" section.

Regression guard. scripts/check-kickoff-guard.sh greps the standing startup docs (docs/handoffs/chicorytv-issue-queue.md, docs/README.md, CLAUDE.md, scripts/select-queue.sh) for #237-as-live-state phrasings ("read #237", "tracker #237", "queue state lives in", …), exempting lines/sections that are explicitly archival. It is wired into the decisions lifecycle CI job so a future PR cannot silently reintroduce the reversed rule.

2026-07-21 — External channel-logo URLs are downloaded and cached at save time; the render path never fetches a logo (#525)

key: graphics.channel-logo-caching · status: active · since: 2026-07-21 · supersedes: none · superseded-by: none Rule: An external http(s) channel-logo URL is fetched, decode-budget-validated, and stored in the image cache under a content-hash name at SAVE time — becoming byte-identical to an uploaded logo — so the render path never fetches a logo over HTTP; a bad URL fails the save with a 422 (BaseError → ValidationProblemDetails). Signals: channel logo url · watermark on-screen bug · paths: ErsatzTV.Infrastructure/Images/RemoteLogoCacher.cs, ErsatzTV.Core/Images/RemoteImageDecodeBudget.cs, ErsatzTV.Application/Channels/Commands/*ChannelHandler*.cs, ErsatzTV/Services/RunOnce/ExternalLogoMigratorService.cs · issues: #525, #511, #502 Mechanics: docs/channels.md → Channel logo & on-screen bug; docs/api-conventions.md → error mapping

ImageElementBase.LoadImage used to fetch an external-URL logo over HTTP inside stream startup, once per playout item. #511 bounded that fetch (timeout, wire cap, redirect cap, decode budgets) but left it in the render path, where a dead/slow/oversized/non-image URL surfaces only as a render-time log line — invisible to the operator who typed it, and re-paid every playout-item transition.

A URL is now an input method, not a storage format. On save, IRemoteLogoCacher fetches the URL (reusing #511's hardened IRemoteImageFetcher), validates it against the shared RemoteImageDecodeBudget (via IRemoteImageValidator), and writes the bytes through IImageCache.SaveArtworkToCache, storing the returned MD5 content-hash name in Artwork.Path. After a successful save the logo is indistinguishable from an uploaded one, so every downstream consumer is unchanged — M3U, XMLTV and the SPA mapper all resolve Artwork.Path to an /iptv/logos/… URL, and the render path finds a local cached file. To refresh a changed remote image the operator re-enters the URL; there is deliberately no refresh button and no staleness/ETag tracking (the content hash makes a re-add of unchanged bytes a natural no-op and of changed bytes a natural new name).

Content-hash name, not a GUID. SaveArtworkToCache already returns an opaque MD5-of-bytes name identical to the upload path, so there is one cache convention rather than two — and dedup + change detection fall out for free. A GUID would deviate for no benefit.

The decode budget now guards uploads too. The byte/wire cap does not bound decoding, so the same RemoteImageDecodeBudget (product of width × height × frames ≤ 50 MP, ≤ 600 frames, enforced on the decoder via DecoderOptions.MaxFrames and re-verified against the decoded image — header frame counts lie, see #511) is applied at BOTH the URL-download path and UploadArtworkHandler. One rule: anything entering the logo cache is budget-checked, however it arrived. This closes a pre-existing gap that this feature would otherwise have widened (a URL logo becoming an unchecked upload).

Narrows ffmpeg.remote-image-fetcher-bounded (#511) and ffmpeg.external-logo-graphics-engine (#502), does not reverse either. #511's IRemoteImageFetcher bounded-fetch primitive and its "not cached, re-fetched per element init" statement REMAIN active for operator-authored YAML image: graphics elements, which still legitimately fetch a URL at render time — only channel logos moved to save-time caching. #502's "external artwork passes through, it is not downloaded into the image cache" still describes the CLIENT-facing consumers (M3U/XMLTV/SPA emit whatever Artwork.Path resolves to) — now a cache URL rather than the raw external URL, because the row no longer holds a URL. So neither predecessor is superseded (both stay active); this is a new decision layered on top, hence supersedes: none — not a keyed supersession.

Existing rows migrate at startup, fail-open. ExternalLogoMigratorService (a run-once BackgroundService, after the schema migrator + DB cleaner) downloads existing URL logo rows into the cache; a row whose download fails is left exactly as-is with a warning naming it, and WatermarkSelector.ChannelLogoWatermarkOptions degrades such a leftover URL to "no on-screen bug" (a warning, never a render-time fetch). The migration is idempotent by construction — a converted row's path is no longer a URL, so a second pass selects it out — and all-or-nothing on cancel (a single trailing SaveChangesAsync).

Accepted residual: the SPA can render a not-yet-migrated external-URL logo as an <img> preview that looks working while the server-side bug won't resolve until the row is re-saved/migrated — a narrow transitional-state cosmetic mismatch, since the startup migration eagerly converts old rows.

2026-07-21 — QSV hardware-frame headroom is a floor, not an operator preference (#529)

key: ffmpeg.qsv-extra-hw-frames-floor · status: active · since: 2026-07-21 · supersedes: none · superseded-by: none Rule: a QSV upload never emits extra_hw_frames below FFmpegState.MinimumQsvExtraHardwareFrames (64); a stored 0 or negative value is treated as "no pool configured" rather than honored literally, because with no headroom any unthrottled read exhausts the pool and the transcode writes nothing at all. Signals: QSV, extra_hw_frames, hwupload, hardware frame pool, ENOMEM, "Could not open encoder before EOF", readrate as an incidental allocation bound · paths: FFmpegState, QsvPipelineBuilder, HardwareUploadFilter, ScaleQsvFilter, DeinterlaceQsvFilter · issues: #529, #350, #516, #519 Mechanics: FFmpegState.MinimumQsvExtraHardwareFrames; FFmpegState.QsvExtraHardwareFrames; QsvPipelineBuilder logs once when a configured value is raised

• extra_hw_frames=0 is not a valid pool size; it is a dead channel waiting for an unthrottled read. FFmpegState.QsvExtraHardwareFrames honored a stored 0 literally, so hwupload=extra_hw_frames=0 reached FFmpeg with no headroom for frames in flight through the filter graph. Measured against the deployed FFmpeg 8.1.2 on one real logged command (software mpeg4 decode → hwupload → vpp_qsv → h264_qsv): the graph fails with -12 (Cannot allocate memory), h264_qsv reports "Could not open encoder before EOF", and zero segments are written. It now clamps to MinimumQsvExtraHardwareFrames (64), which is also the value IfNone already used for an unset profile and the seeded profile default.

• Input throttling was the only thing hiding it, which is why this looked like a #350 regression. Truth table, same command, same binary, only the marked tokens differing:

  readrate	extra_hw_frames	result
  1.05, no burst	0	14 segments, exit 0
  1.05 + burst 2 / 4 / 8	0	ENOMEM, 0 segments
  no readrate at all	0	ENOMEM, 0 segments
  1.05 + burst 8	64	14 segments, exit 0
  no readrate at all	64	14 segments, exit 0

  So the defect predates #350's burst: any work-ahead start (which takes no -readrate) on a pipeline that uploads to QSV was already failing on a profile with 0. The burst did not introduce it — it removed the throttle on every realtime session, converting an intermittent failure into a near-deterministic one, which is how it finally got noticed.

• -readrate was doing load-bearing work nobody had written down. Its stated job is live-TV pacing; it was also incidentally bounding how fast decoded frames enter the filter graph. This is why #350's FFmpeg-level benchmark and #516's argument-generation tests were both green and neither could see it: the burst is bounded in seconds of input, which is not a bound on memory or hardware surfaces. Corrects the #350 entry above, which records the burst as bounded and safe and does not mention hardware frame pools.

• A floor, not a clamp-to-default — and the floor is wider than the evidence. Values above 64 are honored unchanged; values below it are raised. We measured only 0 (fails) and 64 (works), so 1..63 are untested, not known-bad: we raise them rather than trust them, because the failure they risk is a channel that serves nothing at all. That is a deliberate over-reach, and it is not free — extra_hw_frames allocates additional surfaces (64 NV12 1080p surfaces ≈ 190 MiB, ≈760 MiB at 4K), so an operator who deliberately set a small pool on a memory-constrained iGPU silently gets a larger one. QsvPipelineBuilder therefore logs a warning naming both the configured and the applied value, so the override is discoverable rather than silent. If a smaller pool is ever measured safe, lower the floor rather than removing it.

• Fixed at FFmpegState.QsvExtraHardwareFrames, the single point every QSV upload site reads. HardwareUploadFilter, HardwareUploadQsvFilter and WatermarkHardwareUploadFilter read it directly; ScaleQsvFilter and DeinterlaceQsvFilter take values QsvPipelineBuilder passes down from it. One guard covers them all rather than five call sites that can drift apart. (A sixth formatter, SubtitleScaleQsvFilter, also emits extra_hw_frames but is currently dead code — no construction site exists in the solution — so it is not covered by this guard and would need the same value threading if it is ever revived.)

Accepted residual: the floor is applied at render time only, so a stored 0 keeps displaying as 0 in the SPA and over GET /api/v1/ffmpeg/profiles/{id} while FFmpeg receives 64 — the config no longer literally describes the behavior. Render-time was chosen deliberately: it fixes every existing deployment with no DB edit and no migration, which matters because this bug is already failing transcodes in production. New and updated profiles are normalized on save so stored rows converge on the truth, and the warning log closes the discoverability gap for rows that predate it; a backfill migration for old rows was judged not worth the dual-provider cost. Two consequences to know about: the save-time normalization is unconditional on hardwareAcceleration, so a non-QSV profile's stored value moves too (harmless — only the QSV path ever reads it — but it is a stored-state change on a field the user didn't touch); and a machine client that PUTs 0 gets a 200 and then reads back 64, which is a silent transform of a submitted value that the OpenAPI description does not advertise.

2026-07-21 — Check the worked issue before the decision corpus; a closed tracker's comments need no retrofit (#524)

key: docs.tracker-comment-retrofit · status: active · since: 2026-07-21 · supersedes: none · superseded-by: none Rule: When the knowledge exporter flags an over-cap tracker issue and excludes it from ingestion, triage its comments instead of assuming a retrofit is owed — and for each decision-shaped item check the worked issue first, because a tracker session comment is by construction a précis of the fuller closing record posted on the issue it narrates. Applied to #237 (111 comments) this yielded zero records, so server-management#642's "a fact found only in a #237 comment" retrieval row has no valid subject and its interim target (an already-migrated record) is permanent. Signals: tracker retrofit, over-cap issue exclusion, worked-issue-first, tracker-is-not-a-knowledge-store, #237 comment history · paths: docs/tracker-retrofit-triage-237.md · issues: #524, #237, #520, #521, server-management#642 Mechanics: docs/tracker-retrofit-triage-237.md — method, per-comment classification table, totals, and the one candidate that was raised and disproved

Why the worked-issue-first ordering is the load-bearing part. The session protocol that produced #237's log required each session to post its full closing record on the issue it actually worked, and then summarize across issues on the tracker. The tracker entry is therefore the lossy copy. A comment that looks like a unique source is nearly always a précis of a primary the exporter already indexes — so the instinct "the tracker is excluded, therefore its knowledge is orphaned" inverts the real dependency. Checking the corpus first and the worked issue second wastes the effort; the reverse order settles most items in one lookup.

Worked example. Comment [106/111] recorded that #497's music-video metadata reconcile deliberately excludes Guids (not eager-loaded by GetOrAdd, so reconciling would duplicate-insert every scan) and Directors (not add-persisted for MusicVideoMetadata). Genuinely decision-shaped, and genuinely absent from the decision corpus — it survives a corpus-only check and looks like a retrofit target. Issue #497's own closing comment states both exclusions with fuller reasoning, and the exporter ingests it as 497.md. One worked-issue lookup disposes of it.

Scope of the claim — deliberately narrow. The coverage test was applied to decision-shaped items only. Items classified as cross-cutting lore were classified but not coverage-checked, and that bucket is not empty: two facts from comment [109/111] were found to have no home anywhere — scripts/e2e-local.sh's readiness probe hanging on a reused config dir, and the troubleshooting playback API's inability to exercise channel branding. Both were swept into the handoff lore by this PR. So the correct statement is "no decision-shaped orphans," not "no orphans"; a tracker triage that skips the lore bucket will leave real knowledge on the floor.

A zero result is a legitimate outcome, not evidence the triage was done wrong. What would change the answer is a tracker whose sessions did not also write per-issue closing records — one where the tracker genuinely was the primary rather than the narration layer.

2026-07-21 — Work-ahead slots are claimed atomically by the caller, released by the transcode it hands them to (#536)

key: ffmpeg.work-ahead-slot-atomic · status: active · since: 2026-07-21 · supersedes: none · superseded-by: none Rule: workAheadSegmenterLimit is enforced by a single compare-exchange claim on a shared WorkAheadSlots pool taken by the caller of Transcode, which then passes ownership in and gets the release in Transcode's finally — never a Volatile.Read compare in one place and an Interlocked.Increment in another. Signals: work-ahead slot, workAheadSegmenterLimit, check-then-act across an await, unthrottled tune-in, TOCTOU · paths: ErsatzTV.Application/Streaming/WorkAheadSlots.cs, HlsSessionWorker.Run/Transcode, ErsatzTV.Core.Tests/Streaming/WorkAheadSlotsTests.cs · issues: #536, #350, #529, #231, #250 Mechanics: WorkAheadSlots.TryAcquire(limit) CAS loop; Transcode(bool ownsWorkAheadSlot, …)

The defect was structural, not a missing Interlocked. The write side already used Interlocked.Increment, which is why the code read as thread-safe. The read side was a separate, earlier Volatile.Read(ref _workAheadCount) < await GetWorkAheadLimit(...) in Run, and the increment happened later inside Transcode — with at least one await (a DB-backed config read) in between. Interlocked on one half of a check-then-act buys nothing. Three simultaneous tune-ins on prod with workAheadSegmenterLimit: 1 all observed 0 < 1 and all ran with no -readrate.

Why the caller claims and the callee releases. Moving the whole acquire/release pair inside Transcode would be more symmetric, but Run needs the outcome before the call: it sets _state = SeekAndWorkAhead | SeekAndRealtime, and Transcode reads that state on entry (wasSeekAndWorkAhead) to decide whether the item starts at DateTimeOffset.Now or at _transcodedUntil. Folding acquisition inward would have silently changed that branch. Instead the parameter was inverted — Transcode(bool ownsWorkAheadSlot, …) with realtime = !ownsWorkAheadSlot derived on the first line — so the contract is stated in the signature rather than implied by a double negative, and there is exactly one release site guarded by the same flag.

Compare-exchange rather than increment-then-back-off. The issue proposed Interlocked.Increment followed by a decrement when the post-increment value exceeds the limit. That is correct on holder count, but the counter transiently overshoots, so a concurrent reader of Count can observe a value above the limit. The CAS loop never publishes a state that violates the invariant, which matters because the QSV hardware-frame pool sizing (ffmpeg.qsv-extra-hw-frames-floor) is derived from that bound.

Testing shape is inherited from #231/#250. A single Barrier(N) + Task.WhenAll round does not reliably collide on this hardware; the tests hammer 8 threads × 20 000 rounds with a per-round barrier that validates the winner count and resets the pool. The negative control is documented in the test file: reinstate the check-then-act body (not if (true), which trips CS0219 under warnings-as-errors and leaves --no-build running a stale, still-fixed dll). Verified: with the pre-fix shape, 15 912 of 20 000 rounds over-claimed.

2026-07-21 — An on-demand time shift rebuilds the channel's cached XMLTV so the guide can't lag playback (#68)

key: scheduling.ondemand-guide-refresh-on-thaw · status: active · since: 2026-07-21 · supersedes: none · superseded-by: none Rule: When PlayoutTimeShifter.TimeShift slides an on-demand playout's materialized timeline forward on tune-in, it reports the channel numbers whose cached guide is now stale — the shifted channel plus any channels that mirror it — and TimeShiftOnDemandPlayoutHandler enqueues a RefreshChannelData for each, so every affected cached XMLTV fragment is regenerated from the just-shifted PlayoutItem rows. The guide and playback both read the same stored PlayoutItem.Start/Finish, but the guide is served from a cached projection — rewriting the rows without rebuilding the cache would leave the guide advertising a stale timeline. Signals: on-demand resume, bookmark playout, freeze the clock when unwatched, guide/EPG desync, "guide showed S2E3 while tune-in played S1E1", XMLTV cache staleness, mirror channel guide · paths: ErsatzTV.Infrastructure/Scheduling/PlayoutTimeShifter.cs, ErsatzTV.Application/Playouts/Commands/TimeShiftOnDemandPlayoutHandler.cs, ErsatzTV.Application/Channels/Commands/RefreshChannelDataHandler.cs · issues: #68 Mechanics: IPlayoutTimeShifter.TimeShift returns List<string> (shifted channel + its mirrors on a non-zero shift, empty otherwise); handler foreach-enqueues RefreshChannelData on CancellationToken.None

This is what #68 ("resume/bookmark for sequential channels") actually needed. The freeze-when-unwatched, resume-where-you-left-off behavior already existed as ChannelPlayoutMode.OnDemand: Playout.OnDemandCheckpoint persists the viewer's position, UpdateOnDemandCheckpoint advances it (monotonically, minus one segmenter-timeout of rewind-for-context) while watching, and PlayoutTimeShifter slides the whole schedule forward by now − checkpoint on the next tune-in so the item the viewer had reached is active again. Because the shift rewrites GuideStart/GuideFinish alongside Start/Finish, ErsatzTV freezes the guide and playback together — structurally avoiding the free-running-wall-clock desync the issue was filed about (a guide that keeps ticking while playback resumes from a saved spot).

The one gap was cache freshness, not the timing model. RefreshChannelData was enqueued by playout-build and channel/config edits, but not by the on-tune-in time shift, and GetChannelGuideHandler serves a cached .xml fragment (the live-recomputed SPA JSON guide already self-healed). So after a thaw an external EPG client (Jellyfin) could poll a guide reflecting the pre-shift timeline until the next incidental rebuild. BuildPlayoutHandler already refreshes the guide after it time-shifts — including a fan-out to every channel that mirrors the built channel, because RefreshChannelDataHandler refreshes only the one channel it is handed and does not cascade downstream. The tune-in path (TimeShiftOnDemandPlayoutHandler) was unpatched, so this decision replicates both halves: the source channel's guide and its mirrors' guides are rebuilt on thaw. A channel mirroring an on-demand source is an uncommon combination, but omitting it would leave the same desync one hop out.

Why the return-value plumbing rather than enqueuing inside the shifter. PlayoutTimeShifter lives in ErsatzTV.Infrastructure, which cannot reference the RefreshChannelData request type (an ErsatzTV.Application type), so the enqueue must happen in the Application-layer handler. TimeShift therefore returns Option<string> — Some(channelNumber) only when a non-zero offset was actually persisted, None on every early-out (wrong mode, active-and-unforced, empty playout) and on a zero-offset re-tune — so a guide rebuild fires exactly once per real thaw, never on a no-op. The zero-offset None gate is covered by a dedicated non-vacuous test.

Per-viewer resume was deliberately not built. OnDemandCheckpoint is a single value on the playout, so resume is per-channel, not per-viewer. #68 states per-channel suffices for a single household; multi-viewer identity would diverge from this model and is out of scope.

2026-07-21 — Session end fast-forwards the shared checkout; a stale tree serves stale FILES (#541)

key: session.shared-checkout-refresh · status: active · since: 2026-07-21 · supersedes: none · superseded-by: none Rule: Session end runs scripts/refresh-shared-checkout.sh, which fast-forwards /Users/timothy/ersatztv to origin/main (and reinstalls web/node_modules when the lockfile moved), refusing to touch anything unless that tree is on a clean, non-ahead main. Signals: shared checkout, stale kickoff paste, /Users/timothy/ersatztv, session-end protocol, H13 · paths: scripts/refresh-shared-checkout.sh, docs/handoffs/chicorytv-issue-queue.md · issues: #541, #520, #311, #312 Mechanics: docs/handoffs/chicorytv-issue-queue.md → session-end step 6 + the shared-tree lore bullet

The existing rule had a hole, and it is a hole no rule can close. The standing guidance — never commit in the shared tree, never read its HEAD/git log/git status as truth about main — is written entirely around a session reading git state. On 2026-07-21 the trap arrived as a file: the kickoff prompt was pasted out of that tree while it was 81 commits behind, and the handoff doc it carried still described the queue protocol #520 had retired the previous day (read tracker #237, which main now says must not be read for queue state). No git command touched that tree all session, so no discipline check could have fired. Selection happened to go through scripts/select-queue.sh, which is why nothing broke — routing luck, not a control.

So the fix removes the stale condition rather than adding a check, which is what the shared-tree lore bullet already prescribed for its first two failure modes: "a check does not stay true."

The script is deliberately timid, because the tree is shared. It refuses — loudly, exit 0, changing nothing — when the tree is not on main, is dirty, has local commits, or is mid-rebase or mid-merge. It never switches branches, never stashes, never discards. A refusal is a normal outcome, not a failure, because the common reason for one is that another session is legitimately mid-flight.

Two details that testing forced. The first version used npm install, which rewrote package-lock.json and left the shared tree dirty — the exact state the next run refuses on, so the tool would have disabled itself after one use. It uses npm ci, which installs strictly from the lockfile and never writes it. And it asserts the tree is clean at exit, reporting loudly if not: leaving the shared tree dirty is the one outcome that would make this script a net negative.

2026-07-21 — WorkAheadSlots.Release() clamps before decrementing and reports unbalance in-band (#539)

key: ffmpeg.work-ahead-slot-release-never-negative · status: active · since: 2026-07-21 · supersedes: none · superseded-by: none Rule: Release() reads the count and compare-exchanges current - 1 only when current > 0; a release against an empty pool records an unbalanced release and returns false without ever writing a negative value. It never decrements first and clamps afterward. The single caller (HlsSessionWorker.Transcode's finally) logs a warning on the false return. Signals: work-ahead slot release, unbalanced release, negative slot count, over-admit at limit 1, phantom work-ahead room, UnbalancedReleases counter · paths: ErsatzTV.Application/Streaming/WorkAheadSlots.cs, HlsSessionWorker.Transcode, ErsatzTV.Core.Tests/Streaming/WorkAheadSlotsTests.cs · issues: #539, #536, #529, #231, #250 Mechanics: bool Release() CAS loop guarded by current <= 0; call site if (ownsWorkAheadSlot && !_workAheadSlots.Release()) _logger.LogWarning(...)

Why never-negative, given the release is already unreachable-when-unbalanced. Today HlsSessionWorker has exactly one release site, guarded by ownsWorkAheadSlot, so an unbalanced release cannot happen — these were three Low findings from the #536 re-review, filed against the day someone adds a second release site. The pre-#539 shape decremented first (0 → −1) and clamped afterward, leaving a reachable interleaving where a concurrent TryAcquire(limit) reads the −1, sees phantom room, and admits a holder the budget doesn't have (a second acquirer then reads 0 and admits another) — two unthrottled transcodes at limit 1, re-opening the #529 QSV pool exhaustion. Because TryAcquire is the sole, CAS-guarded increment path, a count proven never-negative is exactly what forecloses that over-admit. Clamping before the decrement also records the breakage synchronously on the offending thread, instead of the decrement-first shape where the blame lands on a later, innocent release.

Release() returns bool so the breach is visible in the logs, not only to tests. #536's motivation was "a silently inflated budget with nothing in the logs to find it by," yet UnbalancedReleases was reachable only from a debugger or a test. WorkAheadSlots has no logger by design (it is a leaf primitive), so rather than plumb one in, Release() returns false on an unbalanced release and the caller — which already holds an ILogger — logs the warning. This is the one in-band signal that the ownership contract broke.

UnbalancedReleases can under-count, and that is documented rather than fixed. It only increments when a release finds the pool already empty. An over-release while the count is positive — e.g. one cancelling out a coexisting leak — decrements a real-looking slot and is never recorded, so the two bugs hide each other. There are no false positives (non-zero still means the contract broke), but zero does not prove correctness. Exact accounting would need per-owner tokens, which the #536 "ownership is a discipline, not a token" decision deliberately avoids; the docstring now states the limitation instead.

Negative control (inherited from #231/#250). A dedicated test hammers unbalanced releases on an empty pool while reader threads sample the count; none may ever observe a value below zero. Reinstating the pre-#539 decrement-first body makes it fail (sawNegative > 0 — the readers catch the transient −1); verified. As with the #536 tests, break the primitive by reverting the real body, not if (true) (CS0219 under warnings-as-errors leaves --no-build running a stale, still-fixed dll).

2026-07-21 — from-lineup advanced overrides express "clear to none" via a typed clear enum list (#135)

key: api.from-lineup-clear-to-none · status: active · since: 2026-07-21 · supersedes: none · superseded-by: none Rule: POST /api/v1/channels/from-lineup (and the Auto-Tune per-channel advanced, which reuses the same DTO) distinguishes inherit from clear-to-none with a typed clear enum list on advanced. A field left null/omitted still inherits the template value (unchanged for every existing client); naming a field in clear forces it to none on the new channel even when the template sets one. Sending both a set value and a clear for the same field is a validation error. Signals: clear to none, inherit vs none, advanced override, watermark/filler clear, template-minus-one-setting · paths: ErsatzTV.Core/Api/Channels/CreateChannelFromLineupClearField.cs, ErsatzTV.Application/Channels/Commands/CreateChannelFromLineupHandler.cs, ErsatzTV/Controllers/Api/Requests/CreateChannelFromLineupRequest.cs, web/src/builder/advancedOptions.tsx · issues: #135, #89, #385, #386 Mechanics: CreateChannelFromLineupHandler.ResolveClearable/ValidateClear; SPA applyOverridesToRequest/collectClears/CLEAR sentinel; api-conventions.md §2, spa-conventions.md

Why a clear list, not a sentinel or per-field flags. The gap (found in #89 review) was that the handler resolved every advanced override with advanced.X ?? template.X, so a client sending null always inherited. That is correct for the common path but leaves "this channel should have NO watermark / pre-roll filler even though the template has one" inexpressible. The fix had to keep omitted = inherit byte-stable for existing clients (/api/v1 is frozen-additive, #286), so it is a new optional field, not a reshaping of the existing ones. A {set, value} wrapper per field would have rewritten every field's wire type; a reserved 0 sentinel is magic and asymmetric between int ids and strings; parallel clearX bools add one field per clearable. A single typed enum list is additive, self-documenting, type-checked (an invalid value is a 400 at model binding), covers ids and strings with one mechanism, and extends by adding an enum member. The clearable set is the eight template-inheritable fields where "none" is meaningful: watermark, the four fillers, and the preferred audio/subtitle language + audio title.

Set + clear of the same field is rejected, not silently resolved. The SPA never produces that state (a select is inherit, a value, or None), so the check exists to keep hand-crafted / machine-client requests unambiguous rather than picking a winner. A null/empty set value alongside a clear is fine (redundant, not conflicting).

The enum lives in ErsatzTV.Core, not the Application command, on purpose. The OpenAPI string-enum pass (Startup.UseStringEnumSchemas) scans the Core assembly wholesale; an enum defined in ErsatzTV.Application renders as a bare integer in the spec while every sibling advanced-options enum (PlaybackOrder, ChannelSubtitleMode, …) is a string enum. Placing CreateChannelFromLineupClearField in ErsatzTV.Core/Api/Channels/ makes the wire contract a string enum by construction, matching its siblings.

SPA is id-fields-first; the API is complete ahead of the UI. The Channel Builder + Auto-Tune DetailPanel re-add a real "None" option to the five id selects (watermark + fillers) — the pickers #89 had degraded to "Inherit"-only — routed through a CLEAR overrides sentinel folded into advanced.clear at request-build time (applyOverridesToRequest, so the sentinel never leaks as a field value). The three string clear-fields are covered by the backend enum for machine clients (MCP) but the SPA text inputs keep "empty = inherit"; adding a tri-state to those inputs is deferred, not blocked. This is the deliberate "REST API is a real audience" posture (rest-api-purpose-mcp-and-new-ui).

2026-07-21 — Browser channel preview is a server-declared per-channel capability (#60)

key: api.channel-preview-capability · status: active · since: 2026-07-21 · supersedes: none · superseded-by: none Rule: Whether a channel can be previewed in the browser is declared by the server, not derived by the SPA, as an additive Preview field ({Availability, ManifestUrl, UnavailableReason}) on ChannelResponseModel. Signals: a Play button that does nothing; preview eligibility inferred from a display string; a green preview on a Transport Stream channel being read as validating its configured pipeline · paths: ErsatzTV.Core/Api/Channels/ChannelPreviewResponseModel.cs, ErsatzTV.Application/Channels/Mapper.cs, web/src/screens/channels/ChannelPreviewPanel.tsx · issues: #60, #552 Mechanics: Mapper.GetPreview(StreamingMode, channelNumber, isEnabled, playoutCount) is pure and JWT-agnostic

ChannelPreviewAvailability is one of Available, ForcedHlsOnly, or Unavailable, computed in one place from the real StreamingMode enum plus the channel's enabled/playout state. The SPA renders and acts on it and derives nothing — deriving it client-side would mean keying behavior off Mapper.GetStreamingMode's human-readable display label, where a copy tweak would silently break playback.

Unavailable covers two causes, checked in this order (first match wins): the channel is disabled (IptvController 404s a disabled channel, so preview must not even try), and the channel has zero playouts (a manifest request against one blocks indefinitely). At first pass these two were keying preview on StreamingMode alone, so a disabled or playout-less channel was declared Available and then failed confusingly.

Only the two HLS modes are browser-playable; a browser cannot play the video/mp2t that the Transport Stream modes serve over /iptv/*. Those are declared ForcedHlsOnly: preview is offered only as an explicit opt-in that requests /iptv/channel/{n}.m3u8?mode=segmenter, and is always shown with a caveat that the check does not exercise the channel's configured pipeline. Fatal HLS errors are reported, never auto-recovered — a diagnostic surface must show the fault rather than retry past it; a user-initiated Retry re-issues the manifest request via a real playToken because the manifest GET starts a server-side session, so a byte-identical repeat URL would otherwise be a no-op.

Originally, a JWT-enabled deployment made preview Unavailable (reason IPTV JWT authentication is enabled) because /iptv/* does not accept the SPA's ctv-session cookie and nothing minted a JWT for the browser. #552 closed that: the SPA now mints a short-lived token and appends it as ?access_token=, so this projection no longer inspects JWT status at all. See security.iptv-browser-token.

2026-07-22 — Sequential (YAML) playout gets a golden; Scripted is excluded from the golden net by construction (#381)

key: testing.scripted-playout-golden-deferred · status: active · since: 2026-07-22 · supersedes: none · superseded-by: none Rule: The PlayoutBuildGoldenTests in-memory golden net covers Sequential (YAML) as of #381. Scripted's end-to-end pipeline is excluded — ScriptedPlayoutBuilder runs a user-authored external program that drives the engine over HTTP loopback, which the in-memory harness can't pin — so that full-pipeline (integration) harness is deferred to #563. But the scheduling behavior those scripts drive lives entirely in the in-process SchedulingEngine (the ScriptedScheduleController is a 1:1 pass-through to it), which IS directly unit/golden-testable; the earlier "Scripted is un-golden-able by construction" framing overstated the constraint by conflating transport with engine. #395 extracts that shared switch to ContentEnumeratorBuilder and adds a direct regression net (ContentEnumeratorBuilderTests) over it. Signals: why is there no scripted golden; scripted transport vs engine; SchedulingEngine is in-process testable; Cli.Wrap external process is transport only; ScriptedScheduleController 1:1 pass-through; engine-level scripted regression net; EnumeratorForContent · paths: ErsatzTV.Core.Tests/Scheduling/Goldens/PlayoutBuildGoldenTests.cs, ErsatzTV.Core.Tests/Scheduling/Engine/SchedulingEngineTests.cs, ErsatzTV.Core/Scheduling/Engine/SchedulingEngine.cs, ErsatzTV/Controllers/Api/ScriptedScheduleController.cs, ErsatzTV.Core/Scheduling/ScriptedScheduling/ScriptedPlayoutBuilder.cs · issues: #381, #163, #395, #563 Mechanics: docs/testing.md → Golden-file nets

Sequential (YAML) is golden-able and TZ-independent. SequentialPlayoutBuilder reads a YAML schedule file (Playout.ScheduleFile) rather than a ProgramSchedule/Block calendar, but it is still a pure in-process build: content resolves from an in-memory-SQLite Collection by name, and the count/all/ duration handlers do UTC-only arithmetic off the caller-supplied start. So the Sequential_yaml case uses the exact same harness as Classic/Block — a committed input fixture (Goldens/Fixtures/sequential-schedule.yml) with two count: 2 instructions over one chronological collection — and needs no Assume/TZ guard (verified: it passes, not skips, under a non-UTC TZ, unlike Block). The fixture deliberately avoids the local-time-of-day handlers (wait_until, pad_to_next, pad_until) and shuffle order, which would reintroduce TZ- or seed-dependence. The builder checks the file via the injected IFileSystem but reads bytes with the static System.IO.File, so the test commits a real fixture on disk and stubs only IFileSystem.File.Exists; the JSON-schema validator is stubbed (it loads its schema from a runtime cache folder, irrelevant to characterizing builder output).

Scripted: transport is integration-only, but the engine is in-process testable. ScriptedPlayoutBuilder builds nothing itself — it Cli.Wrap-executes a user-authored external program, hands it http://localhost:{Settings.UiPort} + a build id, and after the process exits reads the result straight off the in-process engine (schedulingEngine.GetState()/GetAnchor()). The program drives the build by calling back over HTTP, but ScriptedScheduleController is a 1:1 pass-through: every action resolves the engine by build id and forwards to a single ISchedulingEngine method (AddCollection, AddCount, PadUntil, …) with no scheduling logic of its own. So "Scripted is un-golden-able" conflates two different things:

• The end-to-end pipeline (real external process + Kestrel on UiPort + HTTP loopback) genuinely is integration-test territory — the in-memory golden harness (shared SQLite, no I/O, deterministic clock) can't pin it, and that harness is deferred to #563. This part of the original decision stands.
• The scheduling behavior the scripts drive is 100% in SchedulingEngine, a plain DI-substitutable object already unit-tested (SchedulingEngineTests, new SchedulingEngine(…4 substitutes…)). It is directly drivable and snapshot-testable with no process and no HTTP — the same way the YAML golden drives its builder, just skipping the script/HTTP front-end. #395 extracts the enumerator-construction switch that the Scripted and Sequential/YAML engines share to ContentEnumeratorBuilder and adds a direct regression net (ContentEnumeratorBuilderTests) over it — the real safety net its dedup needs (not #563).

The #381 "documented decision" arm correctly deferred the pipeline golden; it overstated the case by writing off engine-level coverage too. Scripted scheduling behavior is now covered in-process; only the external-process pipeline remains #563's.