Reported by kettui on PR #374 review: the inline filter that backed
`set_album_api_track_count` only counted rows where `type_ == 'track'`,
but `discogs_client.get_album_tracks` itself accepts both `'track'`
AND empty `type_` as real songs (line 660: `type_ in ('track', '')`).
Releases where Discogs returns some real tracks with an empty `type_`
field would be undercounted, which would silently disagree with the
repair job's fallback `_get_expected_total` path (which calls into
`get_album_tracks_for_source` and therefore uses the client's count).
Extracted the filter into `count_discogs_real_tracks(tracklist)` —
single source of truth for the rule, testable in isolation, and the
worker call site is now a one-liner that names what it's doing. Also
defensive about the input shape: `type_ == None`, missing field, and
empty/None tracklist all handled cleanly.
10 tests pin the behavior:
- empty/missing/None type_ all count as a real track (the kettui case)
- 'heading', 'index', 'sub_track' excluded
- unknown future type strings excluded conservatively
- realistic multi-disc tracklist with mixed shapes counts correctly
- empty/None input returns 0 without raising
Credit: kettui — the PR #374 review comment that flagged this.
Broque Thomas