Pulls the 390-line watchlist auto-scan orchestrator out of `web_server.py`
into a new `core/watchlist/` package. Watchlist (followed-artists scanner
that finds new releases) is a separate domain from kettui's wishlist
(failed-download retry queue), so this lift does not overlap with the
ongoing PR400-style extractions.
What `process_watchlist_scan_automatically` does:
1. Smart stuck-detection guard before acquiring the timer lock —
prevents deadlock when a previous scan flag is dangling past the
2-hour timeout.
2. Inside the timer lock: re-check + set the active scan flag with the
current timestamp.
3. Per-profile expansion (or single-profile when manually triggered):
- Watchlist count check + Spotify auth gate.
- Backfill missing artist images.
4. Initialize a fresh `watchlist_scan_state` dict (the deps property
setter rebinds the web_server.py module-level name so external
sentinel checks via id() comparison still detect the swap).
5. Pause enrichment workers, then call
`WatchlistScanner.scan_watchlist_artists` with a per-event progress
callback that translates scanner events into automation log lines.
6. Post-scan steps (skipped if the scan was cancelled mid-flight):
- Populate discovery pool from similar artists (per-profile).
- Refresh ListenBrainz playlists.
- Update current seasonal playlist (weekly cadence).
- Generate Last.fm radio playlists.
- Sync Spotify library cache.
- Activity feed entry + automation_engine.emit('watchlist_scan_completed').
7. On exception: mark state['status']='error', re-raise so the
automation wrapper records the failure.
8. Finally: resume enrichment workers, clear the scanner's rescan
cutoff, reset the auto-scanning flag.
Strict 1:1 byte parity:
The original mutated `watchlist_auto_scanning`,
`watchlist_auto_scanning_timestamp`, and `watchlist_scan_state` as
module globals (with a leading `global` decl). Here those names are
exposed through the `WatchlistAutoScanDeps` proxy as Python properties
so the lifted body keeps the same `name = value` / `name[key] = value`
shape. Property setters fan writes back to web_server.py via callback
pairs.
Diff vs original after `deps.X` → global X normalization is **zero
differences** apart from the dropped `global` declaration line — Python
doesn't need it once the names are property accesses on the deps object.
390 lines orig = 390 lines lifted, byte-identical body otherwise.
Dependencies injected via `WatchlistAutoScanDeps` (15 fields total) —
Flask app, spotify_client, automation_engine, watchlist_timer_lock, plus
5 callable helpers and 6 property delegate callbacks (paired
get/set for each of the three globals).
Tests: 11 new under tests/watchlist/test_auto_scan.py covering
stuck-detection guard, race-check inside lock, zero-watchlist short-
circuit, unauthenticated Spotify gate, successful scan with all post-
scan steps, automation event emission, activity feed logging,
cancellation mid-scan skipping post-steps, profile-scoped trigger,
flag reset in finally, rescan cutoff clear in finally.
Full suite: 1319 passing (was 1308). Ruff clean.
Broque Thomas