The hand-rolled extractor in internal/library/mbids.go looked up keys that
dhowden/tag never produces, for every supported audio format:
Vorbis (FLAC/OGG): dhowden lowercases keys at parse time (vorbis.go:59),
we looked up MUSICBRAINZ_ALBUMID. Always missed.
ID3v2 (MP3): dhowden stores TXXX frames under bare TXXX/TXXX_N keys
with *tag.Comm values; the Picard tag name is on the value's
Description field, not part of the key. We looked up
TXXX:MusicBrainz Album Id. Always missed.
MP4 (M4A): dhowden stores freeform iTunes atoms under their bare
sub-name. We looked up ----:com.apple.iTunes:MusicBrainz Album Id.
Always missed.
Net effect: every album in the m7-380 boot backfill reported
processed=N, healed=0, skipped=N. The m7-379 enricher gate then
short-circuited NULL on every album, so MBCAA was never queried.
Symptom: "all albums skipped" during cover enrichment.
The pre-existing unit tests passed because they hand-built Raw() maps
with the intended-but-incorrect keys, never round-tripping through
dhowden's parser.
Replace the hand-rolled extractor with dhowden's own mbz sub-package,
which knows the per-format Raw() conventions and uses lowercase
canonical keys (mbz.Album, mbz.Artist). Update both call sites to pass
the full tag.Metadata instead of just Raw(). Rewrite the test with a
stubMeta implementing tag.Metadata, asserting against the actual
per-format Raw() shape, plus a regression guard that pins "uppercase
Vorbis keys must not match" so the v0 bug can't sneak back.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
bvandeusen
947f944fe9