Three compounding bugs froze the UI when dragging the playhead after
playback:
1. Self-deadlock on preview_windows: supply_preview_window /
cancel_preview_windows / cancel_preview_window called
cancel_preview_sequence / cancel_preview_frame while HOLDING the
preview_windows mutex; those calls fire completions synchronously and
the completion locks preview_windows again. Caught by sampling the
hung process: UI thread in cancel_preview_sequence -> TicketSlot::
finish -> completion -> Mutex::lock. Cancels/releases are now
collected under the lock and fired after it is dropped.
2. Seek starvation by shard pinning: a Seek request's scheduler frame
is its ticket id, pinning it to worker (id mod W). The playback
window fills every worker's slots (window slots are only released by
UI-thread consumption), so the seek's pinned worker could have zero
free slots while the UI thread blocked on the seek — permanent
starvation. Seeks (interactive frame / real-time audio) are now
claimable by ANY worker; the no-stealing shard rule stays for
Playback frames (adjacent frames finish together).
3. No per-worker reserve: the global preview_window_capacity reserve is
pool-wide accounting, but exhaustion happens per worker. Playback /
Background claims now leave one credit unused per worker; Seek
claims may use the last slot (they complete on the worker without
UI involvement).
Also: RealEngine::drop cancels the preview windows — ShmFrameRef has no
self-release, so every dropped engine leaked its window's slots from
the shared pool, starving later windows (surfaced as the full-suite
playback_window_supplies_playhead_frames failure once the new probe
test shifted the test schedule). new_sequence_has_default_two_video_
two_audio_tracks now takes the engine test lock (it asserts on the
global undo stack; running lock-free raced parallel undo histories).
New regression probe interactive_seek_renders_without_hanging: play 30
ticks (window fills and holds shm slots), pause, seek, synchronously
render — must not hang. Scheduler tests updated for the reserve and
seek-any-worker contract. OAK_DEBUG_DISPATCH=1 enables the dispatcher
starvation/pool diagnostics used to track this down.
Three real-engine throughput loops (thumbnail pipeline, full-res fill
behind the proxy, playback window supply) failed on machine slowness:
their pass/fail was a wall-clock Instant deadline, so a loaded machine
broke them for speed, not for a broken pipeline. Each loop now counts
engine pumps — machine-speed independent — and asserts the condition
within a bounded number of pumps. The two single-frame worker channel
receives keep a generous 60 s recv_timeout (a one-shot bounded
operation, not a throughput loop).
oak-cli: the integration fixtures moved with the app crate during the
workspace restructure; point the fixture helpers at
../oak-app/tests instead of the (now empty) repo-root tests/.
playback_display_tracks_the_playhead used a 30 s wall-clock deadline as
its pass/fail criterion, so a slow or loaded machine failed the test
for machine speed, not for a broken pipeline — spurious, unrelated to
any race. The loop now terminates on playback-clock progress (playhead
>= 120, ~5 s of playback; the transport advances independently of
render speed, so termination is guaranteed) and the only judgment is
the tracking invariant at that point. No Instant::now() remains.
Verified green on a heavily loaded machine in 84 s.
oakui/component/controls.rs owns the effect/editor controls instead of
reaching into gpui_widgets:
- Slider: horizontal 1:1-cursor drag (the gpui_widgets slider only
responded to vertical cursor movement, so horizontal drags did
nothing), wheel, middle-click reset, arrow keys (Shift = 1/10 step,
Home/End = range ends), and double-click numeric editing (app text
input; commit on blur, Escape cancels). A gesture emits
ValueChanged exactly once on drop — one undoable edit per drag, so
per-mouse-move edits + frame invalidation can no longer freeze the
UI thread.
- CheckBox: click / Space / Enter toggle, request-only contract
(Toggled + set_state), theme colors, optional label.
- ComboBox: click opens a popup list, Up/Down navigate (open) or
change the selection (closed), Enter commits/opens, Escape closes.
- SpinBox: wheel + Up/Down (Shift fine) + Home/End.
The params panel, timeline and dialogs import from the component
module. App-move fallout: i18n packs resolve from the repo-root
assets/i18n via CARGO_MANIFEST_DIR (crates/oak-app is not the repo
root anymore), and the render tests' worker-binary paths point at
../../target/debug/oak-worker.
All crates take the oak-* kebab-case naming (oak-audio, oak-codec,
oak-common, oak-core, oak-ffmpeg-link, oak-node, oak-otio, oak-plugin,
oak-render, oak-storage, oak-task, oak-timeline, oak-undo), with the
lib identifiers rewritten (oakrender:: -> oak_render::, oakcore_rs:: ->
oak_core::, ...) across all 226 referencing files.
The GUI application moves from the workspace root into
crates/oak-app/: src/, build.rs (paths fixed for the new location) and
tests/ travel with it, the root Cargo.toml becomes workspace-only
([workspace] + workspace.package + profiles), and the app package
inherits the workspace version. The screenshots example becomes a
standalone crate examples/simple_player/ with its own Cargo.toml.
Every crate now inherits the single workspace version
(version.workspace = true), and the workflows' crate paths and the
build docs follow the renames.
Validated with a clean cargo check --workspace.
Mike-Solar