The shared optimistic-concurrency parser (ConcurrencyHeaders.ParseIfMatch) classified any
non-canonical/weak/list If-Match value as Malformed → 400. Per RFC 7232 §3.1 a syntactically
-valid entity-tag that simply doesn't strong-match must be 412; 400 is only for a genuine
grammar violation.
- Rewrite ParseIfMatch as a real RFC 7232 entity-tag/list parser: walks the comma-separated
1#entity-tag list, validates each [W/]DQUOTE *etagc DQUOTE member, and collects the strong
members whose opaque text is our canonical decimal. Weak / empty / non-canonical /
out-of-range tags are valid but contribute no version (→ empty set → 412); genuine grammar
violations (unquoted, SP-in-tag, unterminated, garbage) → 400.
- Reshape IfMatchCondition.ExpectedVersion : Option<int> → ExpectedVersions : Option<Seq<int>>
and VersionedAggregateExtensions.CheckVersion → set membership (any strong match proceeds;
empty set always 412). Threads through 10 replace/update commands + handlers + request
mappers + 9 controllers.
- No wire-contract change (400 + 412 already declared on every PUT; the field is header-derived
and internal — no DTO/route/response-type/OpenAPI change).
- Tests: ConcurrencyHeadersTests rewritten for the new classification (lists, weak, empty,
non-canonical → Version/empty-set; grammar violations → Malformed) + new
VersionedAggregateExtensionsTests for CheckVersion membership/empty-set/force-write.
- Docs: api-conventions.md §7a rewritten; decisions.md entry appended.
Refs #253#197fixes#265
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Adds the shared optimistic-concurrency contract so a stale second tab can no longer
silently overwrite a fresher edit. PR1 lands the infra + the Block reference aggregate;
PRs 2–4 fan the same recipe across the other 8 roots (design: #253#issuecomment-8472).
Contract
- `IVersionedAggregate` (`int Version`) on all 9 replace-all roots (ProgramSchedule,
Block, Template, DecoTemplate, Playlist, Collection, Playout, MultiCollection,
RerunCollection), EF-mapped `.IsConcurrencyToken()`; one dual-provider migration
`AddAggregateVersions` (nullable:false, default 0).
- Strong `ETag` of `Version` on the aggregate GET; `If-Match` on the PUT; mismatch →
412 (distinct from the §3a 409 build-lock guard). Successful PUT returns the new ETag.
- `PreconditionFailedError : BaseError` → 412 in `ApiResults.ToErrorResult`;
`ConcurrencyHeaders.ParseIfMatch/SetETag`; malformed If-Match → 400; `*`/absent =
Phase-1 force-write.
Block reference wiring
- Handler: standalone `Either` via `CheckVersion` AFTER validation (never through
`Apply`, which Join()-flattens the subtype to 422), unconditional `Version++`,
`SaveChangesWithConcurrencyGuard` backstop (DbUpdateConcurrencyException → 412).
- `BlockViewModel.Version` (header-only, not echoed in the body); controller sets the
ETag on GET items and on the successful PUT.
- SPA: `client.requestWithMeta` seam; `blocks.getBlockItemsWithMeta` + `replaceBlock`
If-Match/ETag round-trip; `BlockEditor` holds the ETag, sends If-Match, and on 412
opens a blocking "changed elsewhere — reload" dialog.
Tests
- Handler contract tests: stale-If-Match → 412 (no mutation), matching/absent → success
+ bump, no-op save still bumps, and a two-context racing save → 412; proven
non-vacuous (drop `.IsConcurrencyToken()` → the race test fails).
- Controller tests: malformed If-Match → 400, If-Match threaded to the command, ETag on
GET/PUT, 412 passthrough. SPA: requestWithMeta ETag, replaceBlock If-Match, 412 dialog.
Docs: api-conventions §7a, spa-conventions §4a, domain-model glossary, decisions log.
Refs #253
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
timothyandClaude Opus 4.8