fix(rich-markdown-editor): defer non-collab settle/stream mutations off the render phase (flushSync) by waleedlatif1 · Pull Request #6073 · simstudioai/sim

waleedlatif1 · 2026-07-30T00:31:37Z

Summary

Follow-up to #6070. Fixes the second flushSync source on the rich-markdown editor — the non-collaborative streaming/settle path (#6070 fixed the collab editability effect).

The non-collab settle/stream effect called editor.setContent / setEditable / setTextSelection / focus directly in the effect body. setContent mounts the custom node views synchronously through @tiptap/react's flushSync (tiptap#3764), so when the effect runs while React is mid-render it throws "flushSync was called from inside a lifecycle method." Surfaces on the agent-streaming-into-a-non-collab-editor path.

Fix

Small runOffRender helper defers the effect-body view mutations to a queueMicrotask (runs right after the current commit, before paint; no-ops if the editor was torn down).
The settle block is deferred as one microtask so setContent → collapse selection → setEditable → focus keep their exact order.
The streaming rAF tick is untouched — it already runs off-render (inside requestAnimationFrame), so it keeps writing content directly with no added latency.
queueMicrotask is TipTap's own documented remedy for this warning (and what they use internally — PR #3188).

Type of Change

Bug fix

Testing

497 rich-markdown-editor tests pass (incl. stream-settle-selection); tsc + lint + api-validation + boundary + prune green.
Needs a live check: stream an agent into a non-collab markdown file and confirm it renders smoothly (this path is client rendering timing that can't be verified headlessly).

Checklist

Code follows project style guidelines
Self-reviewed my changes
Tests added/updated and passing
No new warnings introduced
I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

…ff the render phase (flushSync) The non-collaborative streaming/settle effect called editor.setContent / setEditable / setTextSelection / focus directly in the effect body. setContent mounts the custom node views synchronously through the @tiptap/react flushSync path (tiptap#3764), so when this effect runs while React is mid-render it throws "flushSync was called from inside a lifecycle method." This is the second flushSync source (the collab editability effect was the first, fixed separately); it fires on the agent-streaming-into-a-non-collab-editor surface. Defer the effect-body view mutations to a microtask via a small runOffRender helper (runs right after the current commit, before paint; no-ops if the editor was torn down). The settle block is deferred as ONE microtask so setContent -> collapse selection -> setEditable -> focus keep their order. The streaming rAF tick is left untouched — it already runs off-render, so it keeps writing content directly. queueMicrotask is TipTap's own documented remedy for this warning. 497 rich-markdown-editor tests (incl. stream-settle-selection) pass; tsc + lint + api-validation + boundary + prune green. Needs a live check: stream an agent into a non-collab markdown file and confirm it still renders smoothly.

vercel · 2026-07-30T00:31:43Z

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cursor · 2026-07-30T00:31:48Z

PR Summary

Low Risk
Client-only TipTap/React timing fix on the non-collab agent-streaming editor path; no auth, persistence, or API changes, with behavior guarded by existing tests including stream-settle selection.

Overview
Fixes React "flushSync was called from inside a lifecycle method" on the non-collaborative agent streaming/settle path in rich-markdown-editor.tsx (follow-up to collab editability deferral in #6070).

setContent, setEditable, setTextSelection, and focus no longer run synchronously in the streaming/settle effect. They go through a runOffRender helper that **queueMicrotask**s work after commit, with a run-sequence token so a superseded effect pass cannot apply stale editor updates. The rAF streaming tick is unchanged and still updates content directly.

On settle, one ordered microtask still does sync body → collapse selection → re-apply editability → optional focus. pendingCollapseRef records when a settle owed a selection collapse; if that microtask is dropped because a newer run superseded it, the steady-sync path still collapses selection so post-stream select-all cannot leave rich-leaf-in-selection decorations stuck on dividers/images.

^{Reviewed by Cursor Bugbot for commit a40a0e0. Configure here.}

greptile-apps · 2026-07-30T00:35:40Z

Greptile Summary

Defers non-collab rich-markdown settle/stream editor mutations off the render phase and invalidates superseded microtasks.

Adds runOffRender (queueMicrotask) so setContent / setEditable / selection / focus are not called directly inside the reconcile effect (avoids TipTap/@tiptap/react flushSync during render).
Tags each effect run with settleRunSeqRef so deferred work runs only for the latest run and a live editor.
Tracks pendingCollapseRef so a selection collapse owed by a dropped settle still runs on a later settle or steady-sync path.
Leaves the streaming requestAnimationFrame content path writing directly (already off-render).

Confidence Score: 5/5

This PR appears safe to merge; the prior microtask-staleness issue is addressed and no remaining blocking failure is evident.

The settle/stream path defers TipTap view mutations off render, drops superseded microtasks with a run sequence token, and carries selection-collapse debt so a dropped settle cannot leave a stale select-all decoration without a later collapse. No blocking failure remains.

Important Files Changed

Filename	Overview
apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/rich-markdown-editor/rich-markdown-editor.tsx	Non-collab reconcile effect defers view mutations via run-token-guarded microtasks and preserves settle selection-collapse across superseded runs; streaming rAF path unchanged.

_{Reviews (4): Last reviewed commit: "fix(rich-markdown-editor): never drop th..." | Re-trigger Greptile}

waleedlatif1 · 2026-07-30T00:37:41Z

@greptile

waleedlatif1 · 2026-07-30T00:37:42Z

@cursor review

cursor

✅ Bugbot reviewed your changes and found no new issues!

1 issue from previous review remains unresolved.

Comment @cursor review or bugbot run to trigger another review on this PR

^{Reviewed by Cursor Bugbot for commit e01aeb6. Configure here.}

…ia a run token runOffRender previously only guarded editor.isDestroyed, so if React ran the next reconcile pass (a newer stream or settle) before a queued microtask flushed, the stale microtask could still apply setContent/setEditable/setTextSelection over the newer state. Tag each effect run with an incrementing token; a deferred mutation applies only when its run is still the latest (and the editor is alive). A run token fits this effect's several early-return exits better than a per-exit cleanup flag. Addresses Greptile/Cursor review.

waleedlatif1 · 2026-07-30T00:44:30Z

@greptile

waleedlatif1 · 2026-07-30T00:44:31Z

@cursor review

…nder a superseded run The run token drops a superseded settle's microtask, but the settle had already flipped its state flags synchronously — so a pre-empting steady-sync run took the non-settle path and never collapsed the selection, leaving a post-stream select-all painting the leaf-in-selection decoration. Track the collapse as a debt (pendingCollapseRef): whichever deferred run ultimately applies — settle or the steady-sync path — clears it, so the collapse runs exactly once on the latest content. Addresses the Cursor review finding.

waleedlatif1 · 2026-07-30T00:53:32Z

@greptile

waleedlatif1 · 2026-07-30T00:53:33Z

@cursor review

cursor

✅ Bugbot reviewed your changes and found no new issues!

Comment @cursor review or bugbot run to trigger another review on this PR

^{Reviewed by Cursor Bugbot for commit a40a0e0. Configure here.}

cursor Bot reviewed Jul 30, 2026

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Comment thread ...ace/[workspaceId]/files/components/file-viewer/rich-markdown-editor/rich-markdown-editor.tsx

chore(rich-markdown-editor): trim verbose flushSync-defer comments

e01aeb6

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waleedlatif1 merged commit caa0a73 into realtime-rooms Jul 30, 2026
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waleedlatif1 deleted the fix-noncollab-flushsync branch July 30, 2026 01:00

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waleedlatif1 commented Jul 30, 2026

Summary

Fix

Type of Change

Testing

Checklist

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Greptile Summary

Confidence Score: 5/5

Important Files Changed

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