Brings the auto-import matcher to picard / beets / roon parity by
reaching for the existing AcoustID-grade infrastructure (typed Album
foundation, integrity check thresholds) and layering id-based exact
matches on top of the fuzzy scorer. Picard-tagged libraries now land
every track with full confidence on the first pass.
Three layered phases in `core/imports/album_matching.match_files_to_tracks`:
1. **MBID exact match** — file has `musicbrainz_trackid` tag, source
returns the same id → instant pair, full confidence, no fuzzy
scoring. Picard's primary identifier; per-recording.
2. **ISRC exact match** — file has `isrc` tag, source returns the same
id → same fast-path, slightly lower priority than mbid (isrc can
be shared across remasters). Both ids normalised before compare
(uppercase + strip dashes/spaces for isrc, lowercase for mbid).
3. **Duration sanity gate** — files in the fuzzy phase whose audio
length differs from the candidate track's duration by more than
`DURATION_TOLERANCE_MS` (3s, matching the post-download integrity
check) are rejected before scoring runs. Defends against the
cross-disc / cross-release / wrong-edit problem the integrity
check used to catch only AFTER the file had already been moved +
tagged + db-inserted.
Tag reader (`_read_file_tags`) extended:
- Reads `isrc` (uppercased, strip / / spaces normalisation deferred
to matcher)
- Reads `musicbrainz_trackid` as `mbid` (lowercased)
- Reads `audio.info.length` and converts to `duration_ms` to match
the metadata-source convention
Metadata-source layer (`_build_album_track_entry`) extended:
- Propagates `isrc` from top-level OR `external_ids.isrc` (spotify
shape — would otherwise be stripped before reaching the matcher)
- Propagates `musicbrainz_id` from top-level OR `external_ids.mbid`
/ `external_ids.musicbrainz`
- Without this layer, fast paths would silently never fire in
production even though unit tests pass — pinned by
`test_album_track_entry_propagates_isrc_and_mbid_from_source`
18 new tests in `tests/imports/test_album_matching_exact_id.py`:
- Direct: `find_exact_id_matches` with mbid, isrc, isrc normalisation,
mbid > isrc priority, spotify-shape `external_ids.isrc`, no-id
empty result, file-used-at-most-once
- Direct: `duration_sanity_ok` within / outside tolerance, missing
durations defer
- End-to-end via `match_files_to_tracks`: mbid match short-circuits
fuzzy scoring, id-matched files excluded from fuzzy phase, duration
gate rejects wrong-disc collisions in fuzzy phase, normal matches
pass through the gate, missing durations fall through, deezer
seconds-vs-ms conversion, full picard-tagged 10-track album via
mbid only
- Production-shape: `_build_album_track_entry` propagates isrc + mbid
from spotify-shape (`external_ids.isrc`) AND itunes-shape (top-
level `isrc`)
Verification:
- 35 album-matching tests pass total (17 helper + 18 fast-path)
- 23 multi-disc tests still pass after the extension (additive)
- Full suite: 2311 passed (+18 new), 1 pre-existing flaky timing test
failure (`test_watchdog_warns_about_stuck_workers` — passes in
isolation, fails only in full-suite runs, unrelated to this PR)
- Ruff clean
For users:
- Picard / Beets / Mp3Tag-tagged libraries (anyone who's organised
their music) get instant perfect-confidence matches every time.
- Soulseek-tagged downloads (which usually carry isrc when sourced
via metadata-aware soulseekers) get the fast path too.
- Naively-named files with no useful tags fall through to the
improved fuzzy + duration-gated path — same correctness as before
for the common case, much harder for the matcher to confidently
pair the wrong file.
- One step closer to standalone-DB feature parity with plex /
jellyfin / navidrome scanners. Acoustid fingerprint fallback
(for files with NO useful tags AND no MBID/ISRC) is the next
followup PR.
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