Two perf gaps that would have failed Cin's review:
# Gap #1: alias lookup fired unconditionally
Pre-fix in this commit, `_resolve_expected_artist_aliases` ran at
the top of every `verify_audio_file` call regardless of whether
the direct artist match would have passed. For users whose library
is mostly same-script (95% of cases), every successful verification
was paying for a wasted DB query (and possibly a wasted MB API
call for un-enriched artists).
Restructured the helper to accept a callable provider instead of a
pre-resolved list. Provider invoked LAZILY only when direct
similarity falls below `ARTIST_MATCH_THRESHOLD`. Verifier passes a
memoising thunk that resolves once across the 3 comparison sites
within one verification.
`_alias_aware_artist_sim` now accepts `aliases` as either:
- iterable of strings (used eagerly — backward compat with tests
that already know the aliases)
- callable returning the iterable (resolved on first need within
a verification)
Happy path (direct match passes): zero DB queries, zero MB calls.
Cross-script case: one resolution shared across 3 sites — same as
the prior contract.
# Gap #2: existing-MBID artists never got alias backfill
Worker's `_process_item` artist branch had an `existing_id` short-
circuit (line 296) that updated MBID status but skipped alias
fetch. Result: every user with an already-enriched library had
MBIDs but NULL aliases on day-one of this PR. Live MB lookup at
verify-time covered them, but at the cost of N live calls for N
artists across the library.
Added one-time backfill: when existing-MBID is found AND
`artists.aliases` for that row is empty, fetch + persist aliases.
Subsequent re-scan cycles short-circuit on the populated column —
no repeated MB calls.
New helper `_artist_aliases_empty(artist_id)` does the cheap NULL
check via direct SQL. Best-effort: defensively returns True on
errors so backfill happens (a redundant MB call is cheaper than
missing the backfill entirely).
# Tests added (9)
`test_acoustid_verification_aliases.py` (+6):
- `TestLazyAliasResolution` (3): no lookup when direct match passes,
lookup fires only when direct fails, lookup memoised across the
3 sites within one verification.
- `TestAliasProviderCallable` (3): iterable passed directly,
callable resolves lazily, callable returning empty falls back to
direct sim.
`test_artist_alias_service.py` (+3):
- `test_existing_mbid_path_backfills_aliases_when_column_empty`
- `test_existing_mbid_path_skips_backfill_when_aliases_already_set`
- `test_existing_mbid_backfill_failure_does_not_break_match`
# Verification
- 79/79 matching tests pass (+9 from prior commit)
- 2537 full suite passes (+9, +79 PR-total)
- Ruff clean
- Backward compat: every prior-commit test still passes (the
iterable-shape API still works alongside the new callable shape)
This is the user-visible commit. The reporter's exact two cases
(Japanese kanji, Russian Cyrillic) now pass verification instead of
being quarantined.
# What changed
Verifier's three artist-similarity sites now route through the
shared `core.matching.artist_aliases.artist_names_match` helper
instead of raw `_similarity`:
- `_find_best_title_artist_match` (per-recording scoring at the
best-match stage)
- Secondary scan when title matches but best-match's artist doesn't
(line ~355 pre-fix)
- Final fallback scan over all recordings (line ~403 pre-fix)
Aliases for the expected artist are resolved ONCE at the top of
`verify_audio_file` via `_resolve_expected_artist_aliases`, which
calls the new `MusicBrainzService.lookup_artist_aliases` chain
(library DB → cache → live MB). Single resolution per verification
regardless of how many AcoustID recordings come back — pinned by
test.
New helper `_alias_aware_artist_sim(expected, actual, aliases)`
wraps the pure helper with the verifier's normaliser
(`_similarity`) and threshold (`ARTIST_MATCH_THRESHOLD`). Returns a
single float so existing threshold-comparison code paths keep their
shape — minimal diff.
# Reporter's cases — verified
Case 1 (issue #442 verbatim):
File: YAMANAIAME by 澤野弘之
Expected: YAMANAIAME by Hiroyuki Sawano
Pre-fix: Quarantined (artist=0%)
Post-fix: PASS (alias '澤野弘之' resolved from MB)
Case 2 (issue #442 verbatim):
File: On the Other Side by Sergey Lazarev
Expected: On the other side by Сергей Лазарев
Pre-fix: Quarantined (artist=7%)
Post-fix: PASS (alias 'Sergey Lazarev' resolved from MB)
Both reproduced as regression tests with stubbed MB service.
# Backward compat
Three test cases pin that no-aliases / failure paths preserve
pre-fix behaviour exactly:
- Clear artist mismatch (different artist, same script) still
FAILs — aliases bridge synonyms, not unrelated artists.
- Exact title + artist match still PASSes regardless of aliases.
- MB service raise → verifier completes with direct similarity
(treats failure as "no aliases available" — same as pre-fix).
Also covers manual import: the import-modal "Search for Match"
flow goes through the same verifier, so the reporter's complaint
that "manual import simply throws them back in quarantine again"
is fixed by the same change.
# Tests added (11)
`tests/matching/test_acoustid_verification_aliases.py`:
- `_alias_aware_artist_sim`: alias bridges score ↑, no-aliases
falls back, aliases don't mask genuine mismatches
- `_find_best_title_artist_match` accepts + uses aliases
- Reporter's case 1 (Japanese) end-to-end
- Reporter's case 2 (Russian) end-to-end
- Backward compat: no-aliases mismatch still fails, exact match
still passes, MB-service-raise doesn't break verification
- Performance: alias lookup fires ONCE per verification regardless
of recording count
# Verification
- 11 new verifier tests pass
- 31 prior service tests pass
- 28 prior helper tests pass
- 294 matching + imports tests pass total (no regression)
- Ruff clean
Broque Thomas