Some tracks don't exist on the sources in the wanted cut — every copy is, say,
the instrumental. The retry engine correctly rejects each (version mismatch) and
gives up, leaving the track missing. New opt-in fallback: once a track's AcoustID
retries are fully exhausted, if every quarantined candidate for it failed the
SAME version mismatch (same matched version, e.g. all instrumental) and there are
>= N of them, accept the best (first-tried = oldest = highest-confidence) one.
Safety rules (core/imports/version_mismatch_fallback.py):
- Version mismatches only. Audio/artist mismatches (different recording) and
integrity/duration failures (truncated/wrong file) never participate.
- All qualifying entries must share the same matched version; a mix
(instrumental + live) is ambiguous → no acceptance.
- Re-import bypasses ONLY the AcoustID gate; integrity/duration/bit-depth still
run, so a truncated or genuinely wrong file is never let through here.
- Reuses the existing quarantine approve_quarantine_entry + re-verify dispatch.
Wired at the AcoustID give-up point in the verification wrapper. Two new
post_processing settings surfaced in the Retry Logic tile (default off):
accept_version_mismatch_fallback + version_mismatch_min_count.
Pure decision core + orchestration covered by tests (11). Acceptance logged at
WARNING with track + matched version.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
