Smoke-testing the just-merged provenance PR against live logs revealed
the new ID-match block was silently no-opping: no [ExtID Match] /
[Provenance Match] log lines despite the code path being live. Tracing
revealed two related gaps in extract_external_ids' source detection:
1. **Underscore-prefixed key.** Deezer / Discogs / Hydrabase clients
tag normalized track dicts with ``_source`` (underscore prefix —
convention used in 8+ places across core/). The extractor only
looked for ``provider`` and ``source``, so Deezer-sourced tracks
silently returned no IDs.
2. **No provider field at all.** Spotify and iTunes raw API responses
carry ``id`` but no provider/source key of any kind. The extractor
couldn't disambiguate the native ``id``, so Spotify-primary scans
would have hit the same silent miss once the user switched primary
sources.
Two-part fix:
- ``extract_external_ids`` now recognizes ``_source`` as another
candidate provider field.
- New optional ``source_hint`` parameter lets the caller supply the
configured primary source as a fallback when the track dict has no
provider field of its own. Track-side provider field still wins
when present (defensive against a wrong hint).
Watchlist scanner now passes ``get_primary_source()`` as the hint so
both naming conventions (Deezer-style _source, Spotify-style no-tag)
get handled uniformly.
6 new regression tests cover:
- _source recognized for Deezer
- _source recognized for Hydrabase (cross-provider mapping)
- _source recognized for Discogs (no library column — verifies
graceful no-crash)
- source_hint disambiguates raw tracks for spotify/itunes/deezer
- track-side provider takes precedence over hint
- None hint defaults safely
Full pytest 1630 passed; ruff clean. After this lands and the server
restarts, watchlist scans should produce [ExtID Match] /
[Provenance Match] log lines for tracks already on disk regardless of
which metadata source the user has configured as primary.
Reported case (CAL): a track already on disk got re-downloaded by the
watchlist scanner on every scan. Library DB had stale album metadata
for the file (track tagged on album "Left Alone") while the metadata
source reported it on a different album ("NPC" single). The
title+artist+album fuzzy block correctly said the album names didn't
match and declared the track missing — but the file's stable external
IDs (Spotify ID, ISRC, etc.) unambiguously identified it as the same
recording.
The earlier compilation-album fix (PR #461) handled qualifier drift
("OST" vs "Music From The Motion Picture"). This case is two
genuinely different album names referring to the same song.
Fix: provider-neutral external-ID short-circuit before the fuzzy
block in `is_track_missing_from_library`. Pulls every recognized ID
off the source track (Spotify / iTunes / Deezer / Tidal / Qobuz /
MusicBrainz / AudioDB / Hydrabase / ISRC), runs a single SELECT
against the indexed external-ID columns on the `tracks` table, and
treats any hit as "track exists in library — don't re-download".
If no IDs are available (older imports without enrichment, library
scans that didn't populate external IDs), falls through to the
existing fuzzy logic so the safety net stays intact.
New `core/library/track_identity.py` module with two helpers:
- `extract_external_ids(track)`: handles dict and object-style track
shapes, direct-field aliases (spotify_id / spotify_track_id /
SPOTIFY_TRACK_ID), and provider-disambiguated native `id` fields
(when track has `provider='deezer'` and `id='X'`, treats X as a
Deezer ID).
- `find_library_track_by_external_id(db, external_ids,
server_source)`: builds an OR of indexed column matches with
IS NOT NULL guards, optional server_source filter that also
passes legacy NULL rows, single-row LIMIT.
ISRC bridges across providers — a library track imported via Deezer
can be matched against a Spotify scan when both sides carry the
same ISRC.
43 regression tests in `tests/test_library_track_identity.py`:
- 9 ID-extraction tests for direct fields (Spotify / iTunes / Deezer /
ISRC / MBID / AudioDB / Hydrabase)
- 8 ID-extraction tests via the provider field (8 providers + source
alias + missing-provider-ignored)
- 7 mixed/defensive tests (multiple IDs, object-style, empty strings,
None track, numeric coercion)
- 8 lookup tests (per-provider + ISRC cross-bridge)
- 3 OR-semantics tests
- 4 server_source filter tests
- 2 ID-column-map sanity tests
Full pytest 1606 passed; ruff clean.
