The probe's only natural exit was "every PGS track has shown a non-forced
display set". A genuinely FORCED track never satisfies that, so on the common
authoring — a forced-narrative track for foreign dialogue — the loop read the
title's entire extent set at 2 MiB per call with no byte cap, no time cap and
no halt check. It was also invoked once per title rather than once per distinct
clip, and a disc's playlists overwhelmingly reference the same few clips (main
feature, play-all, seamless-branch variants), so the same physical extents were
re-read 30-150 times. The two defects multiplied: tens of GB, times the
playlist count, off an optical drive.
Reached via ScanOptions::probe_forced_subtitles, whose only consumer is
`freemkv info -v` (freemkv/src/disc_info.rs). The rip path leaves it off. So
the symptom is `info -v` never returning on an ordinary UHD, not a corrupt rip.
Three changes:
* PROBE_BUDGET_SECTORS caps a probe at 256 MiB. A forced track's display sets
appear throughout the title, so a bounded prefix classifies it; the budget
only decides how long we keep looking for a non-forced set before accepting
the forced verdict.
* ScanOptions::halt is now plumbed in and checked per chunk, so `info -v` is
cancellable. The probe previously took no halt at all.
* A ForcedProbeCache memoises verdicts against the title's exact extent list.
Keying on byte-identical input means a hit cannot change any result — it
only removes the re-read.
Verdict application is factored into apply_verdicts so the cached and freshly
probed paths cannot diverge.
Three tests pin the behaviour, each against a reader that counts sectors and
never ends: the budget stops at exactly PROBE_BUDGET_SECTORS, a cancelled halt
reads zero sectors, and a second title with identical extents costs no further
reads while a different extent list still misses the cache.
Also worth recording: the CLI acceptance harness never exercised `info -v`
against an optical drive — it reads ISOs from local SSD, where a full-extent
read is fast enough to hide both defects.
Matthew Jackson
a39045adf1