Problem: `timeline.place {"audioTrack": "A2"}` on a sequence that has
only A1 placed the clip on A1, overwrote what was there and returned ok.
`track_p` returned `None` both for "no track asked for" and for "that
track does not exist", so callers fell back to the source-patched track.
It also took any first letter other than V as an audio track, accepted
track ids that are not in the sequence, and `split_at(1)` panicked on an
empty or non-ASCII name.
Solution: `track_p` returns `Result<Option<TrackId>>` and takes the
command id, like the other fallible parameter helpers. An absent (or
null) parameter is `Ok(None)` and keeps every default as it was. A name
or id the active sequence does not have is a parameter error
(`EngineError::BadParams`): "invalid parameters for `timeline.place`: no
track A2 in this sequence (`audioTrack`)". All callers propagate it:
timeline.place (`track`, `audioTrack`), timeline.move, timeline.razor,
timeline.setTrack, timeline.setTargeting, sequence.closeGap,
sequence.deleteTrack, sequence.deleteTracks, the go-to-gap commands,
sequence.transcribe and the multicam sync reference track.
Not changed: a `timeline.move` entry without a `clip`, `track` or `time`
is still skipped, as before; only a track that was named and is missing
is an error.
Test: `naming_a_missing_track_is_an_error_not_a_default` in
track_params_tests.rs (missing and hostile names, the error kind, nothing
edited, no undo step, existing tracks by name and id still resolve).
docs/agents.md notes the rule.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
punkhopandClaude Opus 5.5
9d3975a697