Fans the frozen ETag/If-Match/412 recipe (Block reference, #253) onto the
Playlist aggregate:
- ReplacePlaylistItems command carries ExpectedVersion; the handler runs
CheckVersion as a standalone Either after validation (so a stale write
survives as 412, not flattened to 422 by Apply/Join), bumps Version
unconditionally before saving, and persists via
SaveChangesWithConcurrencyGuard (EF concurrency-token backstop).
- PlaylistViewModel carries Version; the items GET sets a strong ETag and
the PUT parses If-Match, threads it into the command, and returns the
refreshed ETag on success (400 on a malformed If-Match).
- Sibling item-adding handlers (AddItemsToPlaylist, AddMovie/Episode/
Season/ShowToPlaylist) bump Version too, since they mutate the same
editor-visible item list.
- SPA: playlists.ts exposes getPlaylistItemsWithMeta and an
If-Match-aware updatePlaylist; PlaylistEditor holds the ETag in a ref,
round-trips it on save, and opens a "changed elsewhere" ConfirmDialog on
412 (mirrors BlockEditor).
Tests: new ReplacePlaylistItemsHandlerConcurrencyTests (stale/match/
force-write/no-op-bump/racing-save), new PlaylistController tests
(ETag on GET items, 400/412/thread-version/force-write on PUT), and a
vitest 412-conflict-dialog test for PlaylistsScreen. dotnet test:
1304/1304 green. web: npm run typecheck clean, npm run build clean,
vitest 664/664 green.
Ref #253 PR2.
timothy
1a8c0f60de