A proper artist/album/track blacklist (distinct from download_blacklist, which
stays untouched). ID-keyed across metadata sources so a ban survives a source
switch; profile-scoped; cascade artist→album→track.
- core/blocklist/matching.py — pure decision core (no I/O): build an index from
rows, candidate_block_reason() walks track→album→artist. Same-source ID match
is primary; artist NAME is a fallback (covers the ID-backfill window);
albums/tracks are ID-only (common titles like "Greatest Hits" must not
false-positive across artists). Source-isolated so a numeric Deezer id can't
collide with a numeric iTunes id of a different entity.
- DB: new `blocklist` table (profile_id, entity_type, name, 4 source-id cols,
match_status) + CRUD, match-row fetch, backfill-pending query, id-backfill
update (COALESCE — fills NULLs only).
- Guard: _wishlist_blocklist_reason at the top of add_to_wishlist — every
auto-acquisition path funnels through it, so one check covers watchlist,
discography backfill, repair, manual add. Fails OPEN (a guard error never
blocks a legitimate add).
- Discovery unified IN: legacy discovery_artist_blacklist is migrated into the
blocklist on upgrade (replicated to every profile so no global ban silently
stops working; idempotent; legacy table kept for rollback). Discovery reads
(hero + personalized-playlist SQL) now union the blocklist, so a new-modal
ban filters discovery too.
Tests: 13 on the pure matcher (cascade, id-vs-name rules, source isolation,
precedence) + 10 on the DB/guard (CRUD, profile isolation, dedup, backfill,
end-to-end wishlist refusal + cascade + the discovery migration upgrade path).
50 blocklist/personalized tests pass.