When a file failed AcoustID verification and got quarantined, the next
auto-wishlist cycle would search for the same track, the deterministic
quality picker would re-select the same (uploader, filename) source,
re-download it, and re-quarantine it. Users woke up to hundreds of
duplicate .quarantined entries from a single bad upload — same source
URL repeatedly, byte-for-byte identical files.
Root cause: `SoulseekClient.filter_results_by_quality_preference` ranks
candidates by quality + bitrate density only. Quarantine history wasn't
consulted, so a high-bitrate FLAC upload with a wrong-track AcoustID
fingerprint kept winning the picker against every other candidate.
Fix shape:
- New helper `core/imports/quarantine.py::get_quarantined_source_keys`
reads every quarantine sidecar's `context.original_search_result`
and returns the set of `(username, filename)` tuples for O(1)
membership checks. Sidecars missing the context field (legacy thin
sidecars written pre-Feb 2026, or orphaned files) and corrupt JSON
are skipped silently — defensive against transient FS / encoding
issues.
- `SoulseekClient._drop_quarantined_sources` runs the membership
filter against incoming TrackResults, drops matches, logs a single
INFO line with the skip count. Called first inside
`filter_results_by_quality_preference` so all four callers
(search-and-download, master worker, validation, orchestrator)
benefit transparently.
- Approving or deleting a quarantine entry removes its sidecar, so
the dedup key disappears from the set on the next search — gives
the user a way to opt back in to a previously-quarantined source
without restarting the app.
7 helper tests cover: missing dir, empty dir, well-formed sidecars
collected as tuples, legacy sidecars skipped, empty source fields
skipped (so empty-string keys can't accidentally drop unrelated
results), corrupt JSON tolerated, duplicate quarantines collapse.
5 integration tests pin: clean candidates pass, known-bad candidates
drop, missing quarantine dir returns input unchanged, filesystem
errors swallowed (defensive), full `filter_results_by_quality_preference`
runs the dedup BEFORE the quality picker — so a high-quality
quarantined source can't win on bitrate.
692 existing download + import tests still green. Cosmetic surface
of the fix is invisible — same UX as today when no quarantine entries
exist; loop only kicks in once a sidecar has been written.
Out of scope: bulk-select / multi-delete UI for the quarantine tab —
S-Bryce mentioned this as a separate pain point in the issue, but
it's its own UX work, not a one-commit drive-by.
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