perf(desktop): stop idle chat re-renders — memo ChatView + stable tile props (salvage #38470) - #77661
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kshitijk4poor merged 1 commit intoAug 3, 2026
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… props, gated adapter re-sync Re-derive of PR NousResearch#38470 on today's main (its target file desktop-controller.tsx no longer exists after the contrib/ refactor; the three surviving ideas are applied at their new homes): - incremental-external-store-runtime: the dep-less setAdapter effect ran every render; gate on [runtime, store] — behavior-preserving because __internal_setAdapter early-exits on identical store. - ChatView is now memo()d, and session-tile hoists its inline arrow props to useCallbacks/module constants so the memo actually holds. - Render-count regression test (mocked Thread) proves an unrelated parent re-render no longer re-renders the chat shell. Credit: idea and original implementation by @hdd69 in NousResearch#38470.
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August 3, 2026 12:40
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Context
Idle chat surfaces were re-rendering constantly: a dep-less
useEffect(() => runtime.setAdapter(store))ran on EVERY render of the chat surface, andChatView— the whole chat shell — was un-memoized while its tile caller passed fresh inline arrow props on each render, so every idle tick (now-tickers, unrelated store updates) re-rendered the entire chat tree. WHO: everyone with a chat open; the cost scales with tiles/panes mounted.What this does
[runtime, store]— behavior-preserving because__internal_setAdapterearly-exits when the store is unchanged (verified at the early-exit site); the effect now simply skips the call instead of making a no-op one every render.ChatViewinmemo()and hoists session-tile's inline arrow props (onAddUrl, onPasteClipboardImage, onPick*, onRemoveAttachment, onRetryResume, noop pin/delete handlers, the transcribe wrapper) to useCallbacks/module constants so the memo actually holds.Provenance
Re-derive of #38470 by @hdd69 (authorship preserved on the commit; attribution mapping merged in #77641). The original PR is unpickable — its main target file
desktop-controller.tsxno longer exists after the contrib/ surfaces refactor, and its branch carries 3 merge commits — but all three of its ideas are alive on today's main and are applied here at their new homes (session-tile.tsx now owns the ChatView call site).Measured impact
Render-count proof at the test level (stated substitution for CPU%): the new test fails on main (unrelated parent render re-renders the chat shell) and passes with the memo chain — that delta is the entire class of idle re-renders eliminated. 8 tests green across chat/index + incremental-external-store-runtime; mutation check: reverting index.tsx fails the render-count test, restore green.
Closes #38470.