Discord report (Skowl): downloaded a compilation album ("High Tea
Music: Vol 1") where every track has a different artist (Eclypse,
Andromedik, T & Sugah, Gourski, etc.) and the AcoustID scanner
flagged every single track as Wrong Song. The file tags had the
correct per-track artist (e.g. "Eclypse" for "City Lights"), but
the scanner compared against the album-level artist ("Andromedik",
the curator). Raw similarity 12% → Wrong Song flag.
# Why the prior multi-value fix didn't help
Foxxify's case (just-merged PR): AcoustID returned multi-value
credit "Okayracer, aldrch & poptropicaslutz!" — primary IS in the
credit. Splitting found it.
Skowl's case: both sides single-value but DIFFERENT artists.
Splitter has nothing to find — Eclypse simply isn't in "Andromedik".
Different bug.
# Cause
Scanner SQL at `core/repair_jobs/acoustid_scanner.py:281` joined
the `artists` table via `tracks.artist_id` which points at the
ALBUM artist (the curator/label-name applied to every row in a
compilation). The `tracks.track_artist` column already holds the
correct per-track artist for compilations — populated by every
server-scan path (Plex `originalTitle`, Jellyfin `ArtistItems`,
Navidrome per-track `artist`) AND the auto-import / direct-download
post-process flow (`record_soulsync_library_entry` writes it when
different from album artist). Scanner just wasn't reading it.
# Fix
```sql
SELECT t.id, t.title,
COALESCE(NULLIF(t.track_artist, ''), ar.name) AS artist,
...
```
Prefers per-track artist when populated, falls back to album artist
for legacy rows / single-artist albums where `track_artist` is NULL.
`NULLIF(t.track_artist, '')` handles the empty-string-instead-of-null
case some legacy rows might have.
# Composes with Foxxify's multi-value fix
For the rare compilation track where AcoustID ALSO returns a
multi-value credit (e.g. compilation track has multiple credited
performers), both paths work together — `track_artist` gives the
correct expected primary, then the helper splits the credit and
finds it.
# Tests added (2)
- `test_load_db_tracks_prefers_track_artist_for_compilation` —
reporter's exact case: track with `track_artist='Eclypse'` AND
`artist_id` pointing at album artist 'Andromedik' resolves to
'Eclypse'. Second track with NULL `track_artist` falls back to
album artist 'Andromedik' (single-artist + legacy compat).
- `test_load_db_tracks_falls_back_when_track_artist_empty_string`
— empty string in `track_artist` (some legacy rows) → NULLIF
returns NULL → COALESCE falls back to album artist.
Both use a real SQLite DB so the COALESCE/NULLIF logic + JOIN
runs against actual schema (SimpleNamespace fakes can't simulate
JOINs).
# Verification
- 6/6 scanner tests pass (2 new + 4 existing)
- 2586 full suite passes (+2 from prior commit)
- Ruff clean
Discord report (Foxxify): the AcoustID scanner repair job flagged
multi-artist tracks as Wrong Song because AcoustID returns the
FULL credit ("Okayracer, aldrch & poptropicaslutz!") while the
library DB carries only the primary artist ("Okayracer"). Raw
SequenceMatcher similarity scored ~43% — well below the 60%
threshold — so the scanner created a finding even though the
audio was correct. User couldn't fix without lowering the global
artist threshold to ~30% (which would let real mismatches through).
# Fix
Extended the shared `core/matching/artist_aliases.py::artist_names_match`
helper (originally lifted for #441) with credit-token splitting.
When the actual artist string contains common separators —
- punctuation: `,` `&` `;` `/` `+`
- keywords (whitespace-bounded): `feat.` `ft.` `featuring` `with`
`vs.` `x`
— the helper splits into individual contributors and checks each
against the expected artist. Primary-in-credit cases now resolve
at 100% instead of 43%.
Two pattern groups because punctuation separators don't need
surrounding whitespace, but keyword separators MUST be
whitespace-bounded — otherwise we'd split artists with `x` /
`with` etc. in their names ("JAY-X" → "JAY-" / "" issue).
Composes with the existing alias path: cross-script multi-artist
credits ("Hiroyuki Sawano" expected, "澤野弘之, FeaturedJp"
actual) work via alias-token-against-credit-token compare.
# Wire-in
Scanner at `core/repair_jobs/acoustid_scanner.py:202` replaces
the raw `SequenceMatcher` call with `artist_names_match`. Pass
RAW artist strings (not pre-normalised by `_normalize`) so the
splitter can recognise separators — `_normalize` strips ALL
punctuation, which destroyed the very tokens the splitter needs.
The AcoustID post-download verifier (`core/acoustid_verification.py`)
already routes through `_alias_aware_artist_sim` which calls the
same helper — gets the multi-value benefit automatically without
a separate wire-in.
# New `split_artist_credit` exported helper
Pure-function helper for callers who want token-level access to
the credit list (debugging, UI, future per-token enrichment). Same
splitter logic, exposed as a top-level function.
# Tests added (14)
`tests/matching/test_artist_aliases.py` (+11):
- `TestSplitArtistCredit` — parametrised across 12 credit-string
formats (comma, ampersand, semicolon, slash, plus, feat./ft./
featuring, with, vs., x, single-token, empty), drops empty
tokens, strips per-token whitespace
- `TestMultiValueCreditMatching` — reporter's exact case
(Okayracer in 3-artist credit → 100%), primary in middle/end of
credit, genuine-mismatch still fails, single-token actual falls
through to direct compare, multi-value composes with aliases,
threshold still respected
`tests/test_acoustid_scanner.py` (+3):
- Reporter's case end-to-end through `_scan_file` — fingerprint
99% / title 100% / multi-artist credit → no finding created
- Genuine artist mismatch still creates finding (no false
suppression of real mismatches)
- `JobResultStub` minimal scaffold for the integration tests
# Verification
- 14 new tests pass (49 helper + 5 scanner total in their files)
- 110 matching + scanner tests pass total
- 2584 full suite passes (+25 from baseline 2559)
- Ruff clean
- Reporter's exact case (Okayracer in `Okayracer, aldrch &
poptropicaslutz!`) now scores 100% match → no Wrong Song flag
