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
Issue #442 — files tagged with one spelling of an artist's name
(Japanese kanji `澤野弘之`) get quarantined when SoulSync expects the
romanized spelling (`Hiroyuki Sawano`). Raw similarity comparison
scored 0% across scripts. MusicBrainz exposes alternate-spelling
aliases on every artist record but the verifier never consulted
them.
This commit adds the pure helper that does the alias-aware
comparison. No I/O, no DB access, no network. Caller supplies the
aliases (looked up from library DB or live MB by later commits in
this PR). Default threshold matches the verifier's existing
`ARTIST_MATCH_THRESHOLD` (0.6) so wiring this in preserves current
pass/fail semantics on the no-alias path.
# API
```
artist_names_match(expected, actual, *, aliases=None,
threshold=0.6, similarity=None)
-> (matched: bool, best_score: float)
```
- Direct compare first (fast path + baseline score)
- If below threshold, score each alias against `actual`
- First alias to clear threshold → match
- Returns the best score across all candidates so callers can log
the score they made the decision on
```
best_alias_match(expected, actual, aliases=None, *, similarity=None)
-> (winner: Optional[str], best_score: float)
```
Companion helper for callers that want to surface WHICH alias
triggered the match (debug logs, UI explanations). No threshold —
purely informative.
# Architectural choices
- **Pure function**: no I/O. Caller (verifier, future matching-engine
consumers) owns alias lookup strategy + threshold tuning.
- **Custom similarity callable**: lets the verifier pass its
parenthetical-stripping normaliser without this module having to
know about it. Defaults to lowercase + SequenceMatcher (matches
the verifier's existing behaviour).
- **Defensive coercion**: aliases input handles None entries, empty
strings, non-string types, sets, tuples, lists — caller may feed
raw MB response data without cleaning first.
- **Backward compat**: `aliases=None` or empty → behaves identically
to a plain similarity check. Paths not yet wired up to alias lookup
see no behaviour change.
# Tests (28)
- Direct compare (no aliases): exact / case / whitespace / fuzzy /
different
- Cross-script with aliases: Japanese ↔ romanized (reporter's case 1),
Cyrillic ↔ Latin (reporter's case 2), symmetric direction, no-match
fallthrough so aliases don't mask genuine mismatches
- Aliases input handling: None, empty, set, tuple, None-entries,
non-string entries
- Threshold: default matches verifier's 0.6, custom stricter, custom
looser
- Custom similarity: applies to both direct + alias compare
- Best-alias-match introspection
- Backward compat parametrised across 5 cases
# What this commit does NOT do
This is the helper module + tests only. Subsequent commits in this
PR populate aliases (MB worker), provide live MB lookup with cache
for un-enriched artists, and wire the helper into the AcoustID
verifier where the quarantine decision actually fires.
Broque Thomas