Followup to the all-libraries-mode commit. Without dedup, a Plex Home
family where two users both have "Drake" in their music libraries
would see "Drake" twice in SoulSync's library list — Plex returns
distinct ratingKeys for each section's copy of the same artist.
Dedup design — applied selectively, NOT everywhere:
- ``_dedupe_artists(artists)``: groups by lowercased title, picks
the canonical entry by ``leafCount`` (more tracks wins). Active
ONLY in all-libraries mode; single-library mode is a no-op fast
path with zero behavior change.
- ``_dedupe_albums(albums)``: same but keys on
(lowercased parentTitle, lowercased title) so two artists with
identically-titled albums (e.g. self-titled releases) stay
separate.
Applied to:
- ``get_all_artists()`` — public listing for the library view
- ``get_library_stats()`` — count matches what user sees in the list
Deliberately NOT applied to:
- ``get_all_artist_ids()`` / ``get_all_album_ids()`` — these feed
removal detection (compare returned ratingKey set against DB-linked
ratingKeys to decide what's been removed). Deduping here would falsely
flag non-canonical ratingKeys as "removed" and prune SoulSync's DB
tracks that are linked to them. Pinned by two CRITICAL tests.
- ``_all_tracks()`` — track count stays raw because the same track
in two sections IS two distinct files / Plex entries, not a logical
duplicate.
- ``_search_general()`` and ``search_tracks`` Stage 1/2 — search
results stay raw so cross-section matches aren't lost. Stage 1
may miss cross-section tracks for the same artist but Stage 2's
server-wide track search catches them.
Logging: when raw vs deduped artist counts differ, ``get_all_artists``
logs both so users can see "Found 4697 artists across all music
sections (4521 unique after cross-section dedup)" — surfaces the
overlap clearly.
Tests: 8 new tests in test_plex_all_libraries.py pin:
- canonical pick by leafCount (artists + albums)
- case-insensitive name match
- single-library no-op path (zero behavior change for those users)
- album dedup keys on (artist, title) so different-artist same-title
albums stay separate
- ``get_all_artists`` listing applies dedup
- ``get_all_artist_ids`` does NOT dedup (CRITICAL — removal detection)
- ``get_all_album_ids`` does NOT dedup (CRITICAL — removal detection)
- ``get_library_stats`` uses deduped counts for artists/albums but
raw count for tracks
Existing pre-stat test updated to use distinct mock instances —
``[MagicMock()] * 5`` creates five references to one mock which now
correctly collapses under dedup.
71/71 media_server tests green, 2162/2162 full suite green.
Honest known limitation acknowledged in WHATS_NEW + version modal:
write-back (genre / poster / metadata updates) targets one
ratingKey at a time — only updates the canonical section's copy of
an artist if it exists in multiple. Other section's copy stays
unchanged. Document and revisit if it matters.