yt_dlp sometimes returns float `duration_ms` for YouTube tracks. The
discovery workers format the duration with `f"{x // 60000}:{(x % 60000)
// 1000:02d}"` — and `:02d` requires an int. When the duration is a
float, the format string raises:
Unknown format code 'd' for object of type 'float'
Caught when running YouTube discovery on a real playlist (bbno$ tracks)
— every track failed with status='Error'.
Pre-existing bug, surfaced now because of yt_dlp returning float
durations on this playlist. Fixed at all 8 sites by casting through
`int()` before the `// 60000` and `% 60000` operations:
- core/discovery/youtube.py: 2 sites in run_youtube_discovery_worker
(cache hit + main result construction).
- web_server.py L29238/L29372: 2 sites in _run_listenbrainz_discovery_worker.
- web_server.py L40112/L40136/L40161/L40178: 4 sites in the YouTube
retry/pre-discovered results assembly path.
The `if duration_ms` / `if dur` guard already protects against None and 0,
so `int(...)` is only called on truthy numeric values.
Tests: 1 new regression test under tests/discovery/test_discovery_youtube.py
(`test_float_duration_does_not_crash_format`) — passes a float
duration_ms and asserts the worker completes without an error result.
Ruff clean.
3c1f614b6e