timothy
fba5233caf
168 records -> docs/decisions/records/<area>/<topic>.md (163 active, 23 dirs) and docs/decisions/archive/<area>/<topic>.md (5 archived). The filename IS the key, so one-active-record-per-key becomes a filesystem property rather than a validator check, and supersession becomes a `git mv`. WHY: the monolith was a concurrency problem before an aesthetic one. A 3,900-line append target made parallel sessions collide -- PR #605 and PR #614 both hit append-vs-append conflicts during routine rebases, and hand-resolving those inside the corpus is exactly the operation the rationale-rewrite guard exists to police. HOW IT IS VERIFIED: a ~170-file diff cannot be meaningfully read, so correctness does not rest on reading it. The parser was taught BOTH formats first, so the body-diff guard parses the old form at the merge-base and the new form at head -- the migration validates itself, no bypass. The proof is a field-level equivalence harness: 168 records before and after, zero lost, zero gained, zero field mismatches, zero rationale bodies differing. Reviewers should scrutinise the harness; it is the actual evidence. What measuring caught that reading would not have: - ~500 lines sit OUTSIDE any record -- decisions.md's lifecycle schema and each topic file's preamble, mostly the only copy. Source files are kept and stripped, never deleted. They also cannot be filed per-area: topic files hold several areas and 4 of 23 areas span several files. - Archive discovery was a non-recursive glob; after the split it found ZERO archived records, surfacing as four bogus "supersedes points to unknown key" errors rather than an obvious failure. - ~32 live docs point into the corpus BY DATE, which the split dangles. Each stripped file now ends with a generated "Records formerly in this file" index, which also rescues the identical breadcrumbs in old issue comments. - decisions.md's "In this file:" list was 97 same-file anchor bullets that the split makes WRONG, not merely stale. Dropped; the generated index replaces them with links that resolve. The equivalence harness now runs against a checked-in FIXTURE, not the live corpus. The earlier version migrated the real tree, which made it a one-shot: the moment the migration landed there was nothing left to move and the tests failed for reasons unrelated to the code. A fixture keeps them testing the SCRIPT rather than the repo's current state. Keys preserved verbatim, warts included: `sched` (12) and `scheduling` (1) remain two directories for one concept. Renaming a key is not a move -- it changes identity, breaks the equivalence proof, and invalidates MemPalace's per-key drawers. Taxonomy normalisation is separate work. refs #610
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key, title, status, since, supersedes, superseded-by, rule, signals, mechanics
| key | title | status | since | supersedes | superseded-by | rule | signals | mechanics |
|---|---|---|---|---|---|---|---|---|
| api.channel-health-object | 2026-07-23 — Channel health = a server-derived `health` object on the channel DTOs, built-timeline detection (#415) | active | 2026-07-23 | api.channel-health-signal@2026-07-17 | none | `ChannelResponseModel`/`ChannelDetailResponseModel` carry a server-derived `health` object (`ChannelHealthResponseModel { Status, Faults[], PlayoutCount, BrokenSourceItemCount }`) computed **read-time** from the built timeline (`Playout.BuildStatus` + upcoming `PlayoutItem → MediaItem.State`, `Finish >= now`), kind-agnostic across all 5 `PlayoutScheduleKind` values; `Status`/`Faults` are const-string classes (`ChannelHealthStatus`, `ChannelFault`), not C# enums, so the SPA hand-maintains the union (mirrors `ChannelPreviewAvailability`). This supersedes #72's "raw fact only, no derived enum, empty-schedule/broken-source deliberately not computed" stance now that the auto-tune taxonomy churn (#383/#384) it was waiting on has landed (see `channel.origin-marker` sibling record, #414). | channel health, ChannelHealthResponseModel, ChannelHealthStatus, ChannelFault, Healthy/Problems/Unknown, NoPlayout/NeverBuilt/BuildFailed/EmptyUpcoming/BrokenSource, built-timeline detection, BuildStatus, PlayoutItem MediaItem.State FileNotFound Unavailable, assessable gate, on-demand suppresses absence signals, Problems rollup filter, willNeverPlay hasProblems · paths: `ErsatzTV.Core/Api/Channels/ChannelHealthResponseModel.cs`, `ChannelRepository.GetAll`, `Mapper.GetHealth`, `GetAllChannelsForApiHandler`, `web/src/screens/ChannelsScreen.tsx`, `api-conventions.md`, `domain-model.md`, `spa-conventions.md` · issues: #415, #72, #71, #383, #384, #414 | `docs/superpowers/specs/2026-07-23-channel-fault-detection-design.md` (full design); `api-conventions.md` (health object shape); `domain-model.md` (channel-health row); `spa-conventions.md` (Problems filter + badge convention) |
#415 was deferred from #72 scope item (b): "empty schedule" and "broken/missing source" faults were real but uncomputed, each explicitly ruled out in the superseded record for a stated reason. This record reverses both rulings now that the blocking condition — the #383/#384 auto-tune status taxonomy churning the DTO shape — has resolved (#414 landed the origin column as a sibling, non-health field).
Built-timeline (kind-agnostic) detection, not per-kind config introspection. Every fault falls out of what the scheduler has already materialized — Playout.BuildStatus ({LastBuild, Success, Message}) for never-built/build-failed, and Playout.Items (the built PlayoutItem timeline, each carrying MediaItemId/MediaItem) for empty-upcoming and broken-source. Because the timeline is the same shape for all five PlayoutScheduleKind values (Classic, Block, Sequential, Scripted, ExternalJson), coverage is by construction — the #71 "verify a shared primitive covers ALL variants" trap, which the superseded record's own EmptyScheduleHealthCheck (Classic-only) fell into, cannot bite here. Scripted, which has no schedule entity to introspect at all, needs no special case. MediaItem.State flips on scan (not build), which rules out a build-time snapshot — detection is necessarily read-time, costed as one bounded GROUP BY PlayoutId aggregate query (not an N+1) over upcoming PlayoutItems.
Five-fault taxonomy, rolled up to one status. NoPlayout (0 playouts, the absorbed #72 fact), NeverBuilt (assessable playout never built), BuildFailed (last build Success == false), EmptyUpcoming (built OK, 0 upcoming items), BrokenSource (≥1 upcoming item pointing at a FileNotFound/Unavailable MediaItem). Rollup: Problems if any contributing playout has a fault, Healthy if any is assessable-and-clean with none, Unknown if nothing is assessable — never a false Healthy and never a false Problems.
The assessable gate distinguishes absence signals from presence signals. NeverBuilt/EmptyUpcoming are inferred from missing content and are suppressed for PlayoutMode == OnDemand (an idle on-demand playout legitimately has no fresh build and drains its timeline between tune-ins — without suppression this is a false-positive storm across every on-demand channel; a suppressed absence signal contributes Unknown, not a false Problems). BuildFailed/BrokenSource are proven by content that is there and is bad, so they stay live in every PlayoutMode — they only fire when the bad thing actually exists and so cannot false-positive on legitimate idleness.
Server owns the rollup so SPA and MCP read one verdict. health rides the same list channels/get channel response both clients already fetch — no second endpoint to correlate by id, and no client re-deriving policy from raw facts (the thing the superseded record explicitly avoided freezing before the taxonomy existed). PlayoutCount is retained unchanged on the DTO for backward compatibility (additive-only /api/v1 freeze); the SPA's "Problems" filter (web/src/screens/ChannelsScreen.tsx, hasProblems, replacing the old single-fault willNeverPlay/"No playout" filter) and per-row badges read health.status/health.faults instead.