The cross-script alias bridge (#442/#586) silently returned [] for some
artists ("Sawano Hiroyuki"). Root cause: the mb-only escape — built exactly
for the case where local string similarity is ~0 (romaji↔kanji) but MB's own
score is decisive — inspected scored[0], the COMBINED-score leader. When an
unrelated same-script decoy outranks the real artist on combined score (decoy:
sim 0.82 + mb_score 83 → combined 0.82, just under the 0.85 bar; real '澤野弘之':
sim 0 + mb_score 100 → combined 0.30, sorted last), the gate saw the decoy's
mb_score 83 (< 95), failed both paths, and cached an empty alias result.
Verification then scored the kanji artist 0% against the romaji expected name
and quarantined every correct file.
Evaluate the MB-SCORE leader independently of combined ranking for the mb-only
escape, and pull aliases from whichever entity actually passed (combined leader
for the combined path, MB-score leader for the mb-only path). The unambiguity
check now compares the top two raw MB scores. Same-script and single-result
paths are unchanged (regression-guarded by the existing #442/#586 tests).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Closes#586. Follow-up to #442 — Cyrillic / kanji canonical names
weren't bridging cross-script comparisons. Reporter case: "Dmitry
Yablonsky" tracks quarantined as audio mismatch with file identified
as "Русская филармония, Дмитрий Яблонский" (4% artist sim) even
though the Cyrillic spelling is just the Russian transliteration.
Codex diagnosed three layered bugs in the alias resolution chain.
This fixes all three.
Bug 1 — fetch_artist_aliases ignores canonical name + sort-name
`core/musicbrainz_service.py:fetch_artist_aliases` only read
`data['aliases']`. For artists where MB's canonical `name` IS the
cross-script form (and the Latin spelling lives only in aliases —
or vice versa), the missing direction never made it into the
returned list. Fix: include both `data['name']` and `data['sort-name']`
alongside the explicit alias entries (deduped, also pulls each
alias entry's sort-name when present).
Bug 2 — lookup_artist_aliases ran search in strict mode only
Strict mode queries `artist:"..."` only and skips MB's alias and
sortname indexes. Cross-script searches found nothing under strict
because the user's Latin input never matches a Cyrillic canonical
name in the artist index. Fix: lifted the search-and-score logic
to a private helper `_search_and_score_artists(name, strict=)` and
fall back to non-strict when strict returns empty OR all results
fail the trust gate. Non-strict (bare query) hits all indexes.
Bug 3 — trust gate weighted local similarity 70%
Combined score = local_sim * 0.7 + mb_score/100 * 0.3. Cross-script
pairs have local sim ~0 → combined ~0.30 → below the 0.85 threshold
→ cached as empty even when MB's own confidence was 100. Fix: added
an MB-only escape — when MB score is >= 95 AND the result is
unambiguous (top result's MB score leads the runner-up by >= 5),
accept regardless of local similarity. The existing combined-score
path stays intact for same-script matches (#442 Hiroyuki Sawano
case still passes via that path).
12 new tests pin every layer:
- fetch_artist_aliases canonical-name inclusion + dedup against
alias entries + missing-canonical handling + exception path
- strict-then-non-strict fallback (empty-strict + low-strict-score)
- trust gate MB-only escape + low-confidence rejection + ambiguity
rejection (two artists same MB score) + same-script regression
- end-to-end reporter scenario with the real `artist_names_match`
helper proving the bridge works for "Русская филармония, Дмитрий
Яблонский" vs expected "Dmitry Yablonsky"
Existing alias tests in `test_artist_alias_service.py` updated to
reflect: canonical name now appears in `fetch_artist_aliases`
output, lookup makes 2 search calls (strict + non-strict fallback)
on first cache miss instead of 1.
Full suite: 3065 passed.
