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
Cin pre-review pass on the false-positive risk. Three tightenings:
# 1. Bumped MB-search trust threshold from 0.6 → 0.85
`MusicBrainzService.lookup_artist_aliases` previously trusted any
MB search match scoring ≥ 0.6 combined (name-similarity + MB
relevance). For distinctive cross-script artists the user-reported
case targets (Hiroyuki Sawano, Сергей Лазарев, etc.) real matches
score ~1.0 — well above 0.85. The 0.6 floor was loose enough to
let in moderate matches for ambiguous names, risking aliases for
the wrong artist getting cached + applied.
Bumped to 0.85. Tighter without rejecting any of the legit
cross-script cases the PR is for.
# 2. Ambiguity gate — skip when results within 0.1 of best
When MB search returns multiple results all scoring high (within
0.1 of the best), the artist name is ambiguous — common name with
multiple distinct artists ("John Smith" returning 10 different
John Smiths). Pulling aliases for any one of them risks the wrong
artist's data bridging incorrectly to a file's tag.
Added explicit ambiguity detection: when 2+ results within 0.1,
skip alias lookup entirely + cache empty. Matches Cin's
"explicit > implicit" — the prior code just picked the highest
score blindly.
# 3. Diagnostic log when alias rescues a comparison
When the alias path triggers a PASS that direct similarity would
have FAILed, emit an INFO log: `Artist alias rescued comparison:
expected='X' vs actual='Y' (direct sim=0.00, alias 'Z' →
score=1.00)`.
Lets future bug reports trace which alias triggered which decision.
Doesn't change behavior — visibility only. Logs ONLY the rescue
case, not happy-path direct matches (no log spam).
# Tests added (5)
`test_artist_alias_service.py` (+3):
- `test_moderate_confidence_match_now_skipped_strict_threshold`
- `test_ambiguous_results_skipped`
- `test_unambiguous_high_confidence_match_succeeds`
`test_acoustid_verification_aliases.py` (+3):
- `test_alias_rescue_emits_info_log` — direct-fail + alias-pass
emits INFO log
- `test_no_log_when_direct_match_succeeds` — happy path quiet
- `test_no_log_when_alias_doesnt_help` — failed path also quiet
# Test infrastructure note
Logging tests use a directly-attached `ListHandler` on
`soulsync.acoustid.verification` (the actual logger name —
dot-separated by `get_logger`), NOT pytest's caplog. Same pattern
as the prior watchdog-test fix — caplog is intermittently flaky
in full-suite runs for soulsync namespace loggers. An owned
handler sidesteps both issues.
# Verification
- 85/85 matching tests pass (+5 from prior commit)
- 2543 full suite passes (+6 from prior, +85 PR-total)
- Ruff clean
- Reporter's Japanese + Russian regression tests still pass —
legit cross-script case (sim ≈ 1.0) clears the new 0.85
threshold easily
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
Previous commit only populated `artists.aliases` for artists the MB
worker had enriched. But the AcoustID verifier (next commit) needs
aliases for ANY expected artist — including:
- Artists not yet in the user's library (first download)
- Artists in the library where MB enrichment hasn't run yet
- Artists where MB enrichment ran but found no MBID (NULL aliases)
This commit adds a multi-tier resolution helper that fills those
gaps without thrashing the MB API.
# Multi-tier resolution
`lookup_artist_aliases(artist_name) -> list[str]`:
1. **Library DB** (fast path): existing `get_artist_aliases` lookup
by name. No network. Most common path once the worker has
enriched everything.
2. **Cache** (existing `musicbrainz_cache` table, entity_type=
`artist_aliases`): a prior live lookup for this name. Empty
cache hit is respected (don't re-query when MB previously had
nothing).
3. **Live MB**: search artist by name → pick highest-confidence
match (combined name-similarity + MB relevance) → fetch aliases
for that MBID → cache the result.
Always returns a list (possibly empty), never raises. Empty result
on any tier means "no alternate spellings found, fall back to
direct match" — identical to the pre-fix behaviour.
# Threshold gate
Live lookup only trusts the MB search result when combined
similarity score >= 0.6. Below that, we'd be guessing at the wrong
artist — searching `John Smith` returns multiple John Smiths and
pulling aliases for one of them could mismatch. Cache the empty
result so we don't keep re-searching the same low-confidence name.
# Performance contract
Critical for the verifier path: 100 quarantine candidates with the
same expected artist must NOT trigger 100 MB API calls. Cache hit
on second + subsequent calls per unique artist name. Verified by
test pinning the call counts.
# Tests added (8)
- Tier 1 library DB hit — no MB API call fired
- Tier 3 live MB lookup → search → fetch → returns aliases
- Tier 2 cache hit on second call — no re-query
- Empty input → empty return + no API call
- Network failure on search → empty + cached so we don't retry
- No search results → empty + cached
- Low-confidence match (sim < 0.6) skipped — defends against
picking the wrong artist
- Library row exists but aliases NULL → falls through to live
lookup (defends against the half-enriched state)
# Verification
- 31/31 service tests pass (8 new + 23 prior)
- Ruff clean
Issue #442 — MusicBrainz exposes alternate-spelling aliases (Japanese
kanji `澤野弘之` for `Hiroyuki Sawano`, Cyrillic `Сергей Лазарев` for
`Sergey Lazarev`, etc.) on every artist record. SoulSync's MB
enrichment worker had access to this data via `get_artist(mbid,
includes=['aliases'])` but wasn't reading or persisting it.
This commit wires the alias fetch into the worker's existing
artist-match path, persists to the new `artists.aliases` column
added in the prior commit, and adds a verifier-friendly read-by-
name lookup so the AcoustID verifier (next commit) can resolve
aliases without an MB round-trip when the artist is in the library.
# New service methods
- `fetch_artist_aliases(mbid) -> list[str]` — calls
`mb_client.get_artist(mbid, includes=['aliases'])`, parses the
alias array, dedupes case-insensitively. Returns empty list on
any failure (missing key, network error, malformed response) so
transient MB outages never trigger stricter quarantine decisions
than the pre-fix behaviour. Empty mbid → no API call.
- `update_artist_aliases(artist_id, aliases)` — persists as JSON
array to `artists.aliases`. Idempotent — overwrites prior value.
Empty list clears the column. None artist_id is a no-op.
- `get_artist_aliases(artist_name) -> list[str]` — reads back by
artist NAME (not id), case-insensitive. Used by the verifier
where the expected artist comes from track metadata — there's no
library row id at quarantine time. Returns empty list for unknown
artists, missing data, or corrupt JSON (defensive against legacy
rows).
# Worker integration
`MusicBrainzWorker._process_item` artist branch:
- After `update_artist_mbid` succeeds, fetch aliases for the matched
MBID and persist via `update_artist_aliases`.
- Best-effort: alias fetch wrapped in try/except, failure logs at
debug level, doesn't regress the match outcome.
- No alias call when the artist didn't match an MBID (nothing to
enrich).
# Tests (23)
- `fetch_artist_aliases`: extracts names from MB response,
case-insensitive dedup, skips empty/null entries, missing-key
fallback, network failure → empty, empty mbid no API call,
verifies `inc=aliases` request param.
- `update_artist_aliases`: persists as JSON, idempotent overwrite,
empty list clears column, None id is no-op.
- `get_artist_aliases`: returns aliases for known artist,
case-insensitive lookup, empty for unknown artist / no-aliases
row, handles corrupt JSON + non-list shape gracefully.
- Worker integration: matched artist triggers fetch + persist,
no alias call when not matched, alias-fetch failure doesn't
break the match outcome.
# Verification
- 23/23 new tests pass
- Ruff clean
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