Independent cold review (Codex) returned BLOCKED. Findings 1, 3 and 4 are fixed here;
each has a regression test proven non-vacuous by a negative control.
1. Blocker — the replaced local path was discarded. The scanner computed localPath but
GetOrAdd only received `incoming`, so the repository re-derived the path from the
UNREPLACED projection. On any install with path replacements, adoption hashed the
server-side path, missed the existing row, ALSO slipped past MediaFileAlreadyExists
(which hashes that same wrong string) and inserted a duplicate row under a server path,
leaving the original collection-linked row identity-less forever. The test harness hid
this because its path-replacement stub was an identity function.
→ GetOrAdd now takes localPath explicitly and never reads the projection's path;
BuildPathReplacement takes a real mapping and the new test genuinely replaces.
3. Medium — GetByItemId matched on ItemId alone, so two media sources presenting the same
item id (cloned Jellyfin DB) resolved to each other's row, letting one library repoint
another's. → filtered by LibraryPath.LibraryId.
4. Medium — a row predating the identity that the server had ALREADY stopped reporting was
never adopted (adoption only runs for an incoming item) and carried no identity, so the
itemId diff could not see it either: it sat Normal and schedulable forever, strictly
worse than the hard delete it replaced. → GetExistingLegacyMusicVideoPaths +
FlagFileNotFoundByPaths reconcile legacy rows by local path, and they are counted into
the #477 empty-fetch guard (on the first scan after this ships they ARE the whole
library, so a guard counting only identity rows would sweep all of them on a transient
empty fetch).
Finding 2 (the issue's Done-when #2) is a scope question, not a defect, and is unchanged:
one file path is still one MediaItem row globally, so this lands music videos at parity
with movies rather than eliminating shared-row trashing. Recorded honestly in the decision
record; raised for an explicit call before the issue is closed.
fixes#496
timothy
6bd1d954bd