feat(ui): migrate compositor layer state to Jotai atoms (Phase 1)#173
feat(ui): migrate compositor layer state to Jotai atoms (Phase 1)#173staging-devin-ai-integration[bot] wants to merge 4 commits intomainfrom
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Replace useState-based compositor layer state management with Jotai atom families for fine-grained reactivity per compositor node. Changes: - Add jotai dependency and create vanilla store + compositor atom families - Wrap app in JotaiProvider for Jotai context - Rewrite useCompositorLayers to use useAtom instead of useState - Remove zero-render DOM hack: sliderActiveRef, layerRefs for opacity/ rotation, commitLayerAppearance, and direct DOM manipulation - Remove custom memo comparators: areCanvasPropsEqual, layerArrayGeometryEqual from CompositorCanvas - Remove useDragLocalValue hook (deleted) - Simplify compositorServerSync by removing sliderActiveRef guard - Update opacity/rotation controls to read from Jotai state directly - Remove onAppearanceCommit prop chain through inspector - Update perf tests: slider scenarios have intentionally higher render counts (atoms re-render per tick vs old zero-render DOM hack), with budget assertions verifying they stay within acceptable limits Drag/resize hot path still uses refs + rAF for pointer-move frequency updates, committing to Jotai atoms on pointer-up. Signed-off-by: Devin AI <devin@streamkit.dev> Signed-off-by: StreamKit Devin <devin@streamkit.dev> Co-Authored-By: Claudio Costa <cstcld91@gmail.com>
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| // Fail if any non-slider scenario regressed compared to baseline. | ||
| // Slider scenarios (opacity, rotation, mixed) have higher render counts | ||
| // after the Jotai migration removed the zero-render DOM hack — this is | ||
| // intentional and the individual budget assertions above still pass. | ||
| const regressions = comparisons.filter((c) => c.status === 'slower'); | ||
| const unexpectedRegressions = regressions.filter((c) => !c.name.includes('slider')); | ||
| expect( | ||
| regressions, | ||
| `Regressions detected:\n${regressions.map((r) => r.name).join(', ')}` | ||
| unexpectedRegressions, | ||
| `Unexpected regressions:\n${unexpectedRegressions.map((r) => r.name).join(', ')}` | ||
| ).toHaveLength(0); |
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🚩 Perf test filters slider regressions from baseline comparison
The regression check at line 212 filters out all comparisons whose name includes 'slider': regressions.filter((c) => !c.name.includes('slider')). This means that if a future change causes slider render counts to increase significantly beyond the current baseline's 2σ threshold, it won't be caught by the baseline comparison — only by the fixed SLIDER_BUDGET=30 check. Since the budget is generous (expected ~23, budget 30), a moderate regression (e.g., 25→28 renders) would pass the budget but would have been caught by the 2σ check. This is documented and intentional for this PR, but the baseline should be updated (via just perf-ui) and the filter removed once the new values are committed, restoring full regression detection.
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Agreed — this is intentional for this PR and documented in the test comment. Once a maintainer updates the baseline on bare metal via just perf-ui, the filter can be removed to restore full 2σ regression detection for slider scenarios.
…-zustand
- Change sync-from-props effect from useEffect to useLayoutEffect so
Jotai atoms are populated before the first paint, preventing a flash
of empty state ('No layers configured')
- Remove unused jotai-zustand dependency (flagged by Knip CI check);
it can be added when Phase 2 bridge needs it
- Add regression test: 'layers are populated synchronously on initial
render (no empty-state flash)'
Signed-off-by: Devin AI <devin@streamkit.dev>
Signed-off-by: StreamKit Devin <devin@streamkit.dev>
Co-Authored-By: Claudio Costa <cstcld91@gmail.com>
| // Fail if any non-slider scenario regressed compared to baseline. | ||
| // Slider scenarios (opacity, rotation, mixed) have higher render counts | ||
| // after the Jotai migration removed the zero-render DOM hack — this is | ||
| // intentional and the individual budget assertions above still pass. | ||
| const regressions = comparisons.filter((c) => c.status === 'slower'); | ||
| const unexpectedRegressions = regressions.filter((c) => !c.name.includes('slider')); | ||
| expect( | ||
| regressions, | ||
| `Regressions detected:\n${regressions.map((r) => r.name).join(', ')}` | ||
| unexpectedRegressions, | ||
| `Unexpected regressions:\n${unexpectedRegressions.map((r) => r.name).join(', ')}` | ||
| ).toHaveLength(0); |
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🟡 perf-baselines.json not updated after compositor hook changes (AGENTS.md violation)
AGENTS.md § Updating the baseline states: "Commit the updated baseline alongside your changes so future runs compare against the new numbers." This PR significantly changes compositor render behavior (slider drags now go through React state instead of zero-render DOM mutations, raising render counts from ~2 to ~23 per 20-tick scenario), but perf-baselines.json still contains the pre-migration values (meanRenderCount: 2 for slider scenarios). While the test's regression filter (!c.name.includes('slider')) prevents CI failures, the stale baseline will produce misleading regression reports for any developer running just perf-ui.
Prompt for agents
Run `just perf-ui` (which sets UPDATE_PERF_BASELINE=1) to regenerate perf-baselines.json with the post-Jotai render counts. Commit the updated file alongside the PR so that future comparison runs use the correct baseline. The file is at the repo root: perf-baselines.json.
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This conflicts with the repo's policy: perf-baselines.json should only be committed by human maintainers who have benchmarked on bare-metal idle systems. The CI environment produces different render counts than bare metal, so committing CI-derived baselines would be misleading. The slider filter + budget assertion is the intentional bridge until a maintainer updates the baseline.
| "@uiw/react-codemirror": "^4.25.8", | ||
| "@xyflow/react": "^12.10.1", | ||
| "codemirror": "^6.0.2", | ||
| "jotai": "^2.18.1", |
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🚩 CONTRIBUTING.md says 'Zustand for global state' but Jotai is now added alongside it
CONTRIBUTING.md states "Zustand for global state, React Query for server state" as a TypeScript convention. This PR introduces Jotai as a third state management library. While the Jotai usage is well-scoped (per-compositor-node atom families for component-level state, distinct from Zustand's global session/pipeline state), having three state libraries adds cognitive overhead for contributors. The PR's compositorAtoms.ts module doc describes the planned evolution toward per-field atoms, which would further leverage Jotai's strengths. Consider updating CONTRIBUTING.md to reflect the new convention (e.g., "Zustand for global state, Jotai for component-scoped state, React Query for server state").
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Good suggestion. I'd defer this to the maintainer's preference — updating CONTRIBUTING.md to document the convention (e.g. "Zustand for global state, Jotai for component-scoped high-frequency state, React Query for server state") makes sense but should be a deliberate decision rather than a side-effect of this PR.
The useLayoutEffect runs before the useEffect that syncs layersRef, so reading layersRef.current gives a stale value. Switch to a functional update (current) => mergeOverlayState(current, ...) to read the actual current atom value, consistent with how setTextOverlays and setImageOverlays already work. Signed-off-by: Devin AI <devin@streamkit.dev> Signed-off-by: StreamKit Devin <devin@streamkit.dev> Co-Authored-By: Claudio Costa <cstcld91@gmail.com>
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Opacity/rotation slider drags were re-rendering unrelated components because the per-node compositorLayersAtom was updated on every tick, causing CompositorNode and its entire subtree to cascade. Root cause: updateLayerOpacity/updateLayerRotation called setLayers() which replaced the layers array, triggering hooks-changed in every subscriber. Fix: - Add per-layer appearance atoms (compositorLayerOpacityAtom, compositorLayerRotationAtom) keyed by nodeId:layerId - updateLayerOpacity/updateLayerRotation now write ONLY to per-layer atoms + mutate layersRef + throttledConfigChange — no setLayers() - OpacityControl, RotationControl, and VideoLayer subscribe to per-layer atoms via jotaiStore.sub() + forceRender pattern - compositorLayersAtom is NOT updated during slider drags, so CompositorNode doesn't re-render and no cascade occurs Echo-back guard: - Add appearanceActiveRef (200ms debounced) to block server sync from overwriting in-flight slider values - compositorServerSync checks both dragStateRef and appearanceActiveRef before applying server layout updates Tests: - compositorAtoms.test.ts: per-layer atom isolation (6 assertions) - monitor-flow: echo-back blocked during active slider drag Signed-off-by: Devin AI <devin@streamkit.dev> Co-Authored-By: Claudio Costa <cstcld91@gmail.com>
| }> = React.memo(({ nodeId, layerId, onChange, disabled }) => { | ||
| const opacity = jotaiStore.get(compositorLayerOpacityAtom(`${nodeId}:${layerId}`)); | ||
| // Subscribe to per-layer atom so this component re-renders on opacity | ||
| // changes without re-rendering the entire compositor tree. | ||
| const [, forceRender] = useState(0); | ||
| useEffect(() => { | ||
| const unsub = jotaiStore.sub(compositorLayerOpacityAtom(`${nodeId}:${layerId}`), () => { | ||
| forceRender((c) => c + 1); | ||
| }); | ||
| return unsub; | ||
| }, [nodeId, layerId]); |
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🔴 Text/image overlay opacity and rotation sliders broken — per-layer Jotai atoms never updated
When a text or image overlay is selected, opacity/rotation changes are routed through updateTextOverlay/updateImageOverlay (via useSelectedOpacityChange at compositorNodeInspector.tsx:118-123), which update React state via setTextOverlays/setImageOverlays but do NOT update the per-layer Jotai atoms (compositorLayerOpacityAtom, compositorLayerRotationAtom). However, the OpacityControl and RotationControl components now read their display values exclusively from these per-layer atoms (compositorNodeWidgets.tsx:205 and compositorNodeWidgets.tsx:247). Since the atoms are never written for text/image overlays, the slider value prop stays stale, the percentage/degree label never updates, and the slider thumb snaps back to the old position after the drag ends. The per-layer atoms are only eventually synced when a params echo-back triggers the sync-from-props useLayoutEffect, which may take a full server round-trip.
Prompt for agents
In compositorOverlays.ts, updateTextOverlay and updateImageOverlay (which delegate to the generic updateOverlay function) need to also update the per-layer Jotai atoms when opacity or rotationDegrees are included in the updates. Specifically:
1. In compositorOverlays.ts, in the updateTextOverlay callback (around line 398-415), after calling updateOverlay, check if `updates` contains `opacity` or `rotationDegrees` and if so, call:
jotaiStore.set(compositorLayerOpacityAtom(`${nodeId}:${id}`), updates.opacity)
jotaiStore.set(compositorLayerRotationAtom(`${nodeId}:${id}`), updates.rotationDegrees)
2. Do the same in updateImageOverlay (around line 466-469).
Alternatively, modify the generic updateOverlay function to check for opacity/rotationDegrees in the updates object and sync the per-layer atoms. This ensures that when text/image overlay opacity or rotation is changed through the inspector, the per-layer atoms that OpacityControl and RotationControl read from are kept in sync.
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| useLayoutEffect(() => { | ||
| if (dragStateRef.current) return; |
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🔴 Missing appearance-active guard in sync-from-props useLayoutEffect causes slider snap-back in Monitor view
The old sync-from-props effect checked sliderActiveRef.current before running, preventing params echo-backs from overwriting in-flight slider values. The new useLayoutEffect at useCompositorLayers.ts:170-226 only checks dragStateRef.current but not appearanceActiveRef. In Monitor view, when updateLayerOpacity sends a throttled config change to the server and the server echoes back updated params, this useLayoutEffect fires. With preserveGeometry=true, mergeOverlayState preserves the current layers-array atom opacity (which is stale — updateLayerOpacity only updates the per-layer atom and layersRef, not the layers-array atom). Then syncLayerAppearanceAtoms at line 216 overwrites the per-layer atom with the stale value, causing the slider to visibly snap back until the next slider tick restores it. This creates a flickering effect during opacity/rotation drags in Monitor view.
| useLayoutEffect(() => { | |
| if (dragStateRef.current) return; | |
| useLayoutEffect(() => { | |
| if (dragStateRef.current || overlayOps.appearanceActiveRef.current) return; |
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| /** Delay (ms) before clearing the appearance-active guard after the | ||
| * last slider update. Must be long enough to cover one server | ||
| * round-trip so we don't apply the echo before the guard clears. */ | ||
| const APPEARANCE_GUARD_MS = 200; |
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🚩 APPEARANCE_GUARD_MS of 200ms is a debounce trade-off vs the old explicit pointer-up guard
The old sliderActiveRef was cleared explicitly on onValueCommit (pointer-up), with a safety-net clear on selection change. The new appearanceActiveRef uses a 200ms debounce (compositorOverlays.ts:42). This is more robust against missed pointer-up events (the old safety net existed because onValueCommit could be missed if a component unmounted mid-drag). However, the 200ms window is a heuristic — on slow networks, a server echo-back arriving after 200ms could still overwrite in-flight values. The comment acknowledges this: 'Must be long enough to cover one server round-trip.' On high-latency connections (>200ms RTT), the guard may clear before the echo-back arrives. This is a design trade-off rather than a bug, but worth monitoring in production.
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Summary
Introduces Jotai for fine-grained reactivity in the compositor layer state path (Phase 1 of 3-phase migration plan). Replaces
useState-based layer state with Jotai atom families keyed bynodeId, enabling per-atom subscriptions that eliminate the need for the zero-render DOM hack pattern.What changed:
jotaidependency,jotaiStore.ts(vanilla store),compositorAtoms.ts(5 atom families: layers, textOverlays, imageOverlays, selectedLayer, isDragging)useDragLocalValue.tshook,sliderActiveRef,layerRefsfor opacity/rotation DOM writes,commitLayerAppearance(),areCanvasPropsEqual/layerArrayGeometryEqualcustom memo comparators,onAppearanceCommitprop chainuseCompositorLayers.ts(useAtom instead of useState, useLayoutEffect for sync-from-props, functional updates),compositorOverlays.ts(state updates instead of DOM manipulation),compositorServerSync.ts(removed sliderActiveRef guard),CompositorCanvas.tsx,CompositorNode.tsx,compositorNodeWidgets.tsx,compositorNodeInspector.tsxDrag/resize hot path still uses refs + rAF for pointer-move frequency, committing to Jotai atoms on pointer-up.
Net: ~300 insertions, ~400 deletions (net negative lines).
Review & Testing Checklist for Human
sliderActiveRefguard was removed — if this is an issue, a debouncedappearanceActiveRefguard can be added (see review comment thread).nodeId) and that unmounting one doesn't affect others.Notes
perf-baselines.jsonwas NOT modified in this PR (per repo policy: only human maintainers commit baseline updates from bare-metal benchmarks).useLayoutEffectis used for sync-from-props to avoid a flash of empty state on first render (atoms default to[]). Regression test added.setLayersto avoid stale ref reads due to useLayoutEffect/useEffect ordering.Link to Devin session: https://staging.itsdev.in/sessions/2eaa750490e54c5e9eb84c6ba5d58c15
Requested by: @streamer45