The existing fallback (pipeline.py:1084) only ran inside
post_process_matched_download_with_verification — i.e. when a file *was*
downloaded and AcoustID retries were fully exhausted. If the retry *search*
itself found zero valid candidates (source returned nothing, or all failed
HiFi validation), the task was marked not_found and the fallback was never
reached, even though the quarantine already held N version-mismatch entries.
Fix: add try_version_mismatch_fallback to TaskWorkerDeps; in the "no valid
candidates" path of task_worker, invoke it before marking not_found when
is_quarantine_retry. Wired in _build_task_worker_deps via a new helper
(_try_version_mismatch_fallback_for_worker) that calls
try_accept_version_mismatch_fallback directly with the track's title and
artist and a reprocess lambda over _post_process_matched_download_with_verification.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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