🪢 refactor: Eliminate Unnecessary Re-renders During Message Streaming#12454
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Pull request overview
Refactors message rendering to reduce unnecessary re-renders during streaming by preventing isSubmitting changes from cascading through memoized message components.
Changes:
- Introduces a stable
TMessageChatContextobject passed from wrapper components into memoized render components, avoidinguseChatContextsubscriptions insideReact.memo. - Switches
isSubmittingusage to ref-backed access patterns (getter/ref) to keep callbacks stable and reduce prop churn. - Moves “effective
isSubmittingonly for latest message” computation into wrapper components and simplifies memoized components accordingly.
Reviewed changes
Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.
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| File | Description |
|---|---|
| client/src/hooks/Messages/useMessageProcess.tsx | Stabilizes handleScroll against isSubmitting changes using a ref. |
| client/src/hooks/Messages/useMessageActions.tsx | Stops subscribing to ChatContext; consumes a passed chatContext and ref-guards regenerate. |
| client/src/components/Messages/MessageContent.tsx | Creates/passes stable chatContext; only passes isSubmitting to latest message. |
| client/src/components/Messages/ContentRender.tsx | Accepts chatContext prop; relies on wrapper-computed effective isSubmitting. |
| client/src/components/Chat/Messages/ui/MessageRender.tsx | Accepts chatContext prop; relies on wrapper-computed effective isSubmitting. |
| client/src/components/Chat/Messages/Message.tsx | Creates/passes stable chatContext; only passes isSubmitting to latest message. |
| client/src/common/types.ts | Adds TMessageChatContext type documenting the stable context/getter pattern. |
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Defines a type for a stable context object that wrapper components pass to memo'd message components, avoiding direct ChatContext subscriptions that bypass React.memo during streaming.
useMessageActions previously called useChatContext() inside memo'd components (MessageRender, ContentRender), bypassing React.memo when isSubmitting changed during streaming. Now accepts a stable chatContext param instead, using a ref for the isSubmitting guard in regenerateMessage. Also stabilizes handleScroll in useMessageProcess by using a ref for isSubmitting instead of including it in useCallback deps.
Wrapper components (Message, MessageContent) now create a stable chatContext object via useMemo with a getter-backed isSubmitting, and compute effectiveIsSubmitting (false for non-latest messages). This ensures MessageRender and ContentRender (both React.memo'd) only re-render for the latest message during streaming, preventing unnecessary re-renders of all prior messages and their SubRow, HoverButtons, and SiblingSwitch children.
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…ders buildTree creates new message objects on every streaming update for ALL messages, not just the changed one. This defeats React.memo's default shallow comparison since the message prop has a new reference even when the content hasn't changed. Custom areEqual comparators now compare message by key fields (messageId, text, error, depth, children length, etc.) instead of reference equality, preventing unnecessary re-renders of SubRow, Files, HoverButtons and other children for non-latest messages.
- Wrap StopButton in React.memo - Wrap AudioRecorder in React.memo, use ref for isSubmitting in onTranscriptionComplete callback to stabilize it - Remove useChatContext() from FileFormChat (bypassed its memo during streaming), accept files/setFiles/setFilesLoading as props from ChatForm instead
ChatForm re-renders frequently during streaming (ChatContext changes). This caused StopButton and AttachFileChat/AttachFileMenu to re-render despite being memo'd, because their props were new references each time. - Wrap handleStopGenerating in a ref-based stable callback so StopButton always receives the same function reference - Create stableConversation via useMemo keyed on rendering-relevant fields only (conversationId, endpoint, agent_id, etc.), so AttachFileChat and FileFormChat don't re-render from unrelated conversation metadata updates (e.g., title generation)
…mChat Both components used useFileHandling() which internally calls useChatContext(), bypassing their React.memo wrappers and causing re-renders on every streaming chunk. Switch to useFileHandlingNoChatContext() which accepts file state as parameters. The state (files, setFiles, setFilesLoading, conversation) is passed down from ChatForm → AttachFileChat → AttachFileMenu as props, keeping the memo chain intact.
- Re-export useFileHandlingNoChatContext from hooks barrel - Import from ~/hooks instead of direct path for test compatibility - Add useToastContext mock to @librechat/client in AttachFileMenu tests since useFileHandlingNoChatContext runs the core hook which needs it - Add useFileHandlingNoChatContext to ~/hooks test mock
- Switch AttachFileMenu from useSharePointFileHandling (subscribes to ChatContext) to useSharePointFileHandlingNoChatContext with explicit file state props - Memoize ChatForm textarea onFocus/onBlur handlers with useCallback to prevent TextareaAutosize re-renders (inline arrow functions and .bind() created new references on every ChatForm render) - Update AttachFileMenu test mocks for new hook variants
ChatForm was re-rendering on every streaming chunk because it subscribed to useChatContext() internally, and the ChatContext value changed frequently during streaming. Extract context subscription into a ChatFormWrapper that: - Subscribes to useChatContext() (re-renders on every chunk, cheap) - Stabilizes conversation via selective useMemo - Stabilizes handleStopGenerating via ref-based callback - Passes individual stable values as props to ChatForm ChatForm (memo'd) now receives context values as props instead of subscribing directly. Since individual values (files, setFiles, isSubmitting, etc.) are stable references during streaming, ChatForm's memo prevents re-renders entirely — it only re-renders when isSubmitting actually toggles (2x per stream: start/end).
- Wrap newConversation in ref-based stable callback in ChatFormWrapper (was the remaining unstable prop causing ChatForm to re-render) - Wrap CollapseChat in React.memo to prevent re-renders from parent
useAddedResponse returned a new object literal on every render, causing AddedChatContext.Provider to trigger re-renders of all consumers (including ChatForm) on every streaming chunk. Wrap in useMemo so the context value stays referentially stable.
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Finding 1: Switch AttachFile.tsx from useFileHandling to useFileHandlingNoChatContext, closing the optimization hole for standard (non-agent) chat endpoints. Finding 2: Replace content reference equality with length comparison in both memo comparators — safer against buildTree array reconstruction. Finding 3: Add conversation?.model to stableConversation deps in ChatFormWrapper so file uploads use the correct model after switches. Finding 4/14: Fix stableNewConversation to explicitly return the underlying call's result instead of discarding it via `as` cast. Finding 5/6: Extract useMemoizedChatContext hook shared by Message.tsx and MessageContent.tsx — eliminates ~70 lines of duplication and stabilizes chatContext.conversation via selective useMemo to prevent post-stream metadata updates from re-rendering all messages. Finding 8: Use TMessage type for regenerate param instead of Record<string, unknown>. Finding 9: Use FileSetter alias in FileFormChat instead of inline type. Finding 11: Fix pre-existing broken throttle in useMessageProcess — was creating a new throttle instance per call, providing zero deduplication. Now retains the instance via useMemo. Finding 12: Initialize isSubmittingRef with chatContext.isSubmitting instead of false for consistency. Finding 13: Add ChatFormWrapper displayName.
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The length-based comparison (content?.length) missed updates within existing content parts during streaming — text chunks update a part's content without changing the array length, so the comparator returned true and skipped re-renders for the latest message. Reference equality (===) is correct here: buildTree preserves content array references for unchanged messages via shallow spread, while React Query gives the latest message a new reference when its content updates during streaming.
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The local isSubmittingRef was stale for non-latest messages (which don't re-render during streaming by design). chatContext.isSubmitting is a getter backed by the wrapper's ref, so reading it at call-time always returns the current value regardless of whether the component has re-rendered.
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HoverButtons uses isSubmitting via useGenerationsByLatest to disable regenerate and hide edit buttons during streaming. Passing the effective value (false for non-latest messages) re-enabled those actions mid-stream, risking overlapping edits/regenerations. Use chatContext.isSubmitting (getter, always returns current value) for HoverButtons while keeping the effective value for rendering-only UI (cursor, placeholder, streaming indicator).
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March 29, 2026 20:10
- Add isSubmitting to chatContext useMemo deps in useMemoizedChatContext so HoverButtons correctly updates when streaming starts/ends (2 extra re-renders per session, belt-and-suspenders for post-stream state) - Change conversation?.messages?.length dep to boolean in ChatFormWrapper stableConversation — only need 0↔1+ transition for landing page check, not exact count on every message addition - Add defensive comment at chatContext destructuring point in useMessageActions explaining why isSubmitting must not be destructured - Remove dead mockUseFileHandling.mockReturnValue from AttachFileMenu tests
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- Extract complex expression (conversation?.messages?.length ?? 0) > 0 to hasMessages variable for static analysis in ChatFormWrapper - Add eslint-disable for intentional isSubmitting dep in useMemoizedChatContext (forces new chatContext reference on streaming start/end so HoverButtons re-renders)
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…danny-avila#12454) * refactor: add TMessageChatContext type for stable context passing Defines a type for a stable context object that wrapper components pass to memo'd message components, avoiding direct ChatContext subscriptions that bypass React.memo during streaming. * perf: remove ChatContext subscription from useMessageActions useMessageActions previously called useChatContext() inside memo'd components (MessageRender, ContentRender), bypassing React.memo when isSubmitting changed during streaming. Now accepts a stable chatContext param instead, using a ref for the isSubmitting guard in regenerateMessage. Also stabilizes handleScroll in useMessageProcess by using a ref for isSubmitting instead of including it in useCallback deps. * perf: pass stable chatContext to memo'd message components Wrapper components (Message, MessageContent) now create a stable chatContext object via useMemo with a getter-backed isSubmitting, and compute effectiveIsSubmitting (false for non-latest messages). This ensures MessageRender and ContentRender (both React.memo'd) only re-render for the latest message during streaming, preventing unnecessary re-renders of all prior messages and their SubRow, HoverButtons, and SiblingSwitch children. * perf: add custom memo comparators to prevent message reference re-renders buildTree creates new message objects on every streaming update for ALL messages, not just the changed one. This defeats React.memo's default shallow comparison since the message prop has a new reference even when the content hasn't changed. Custom areEqual comparators now compare message by key fields (messageId, text, error, depth, children length, etc.) instead of reference equality, preventing unnecessary re-renders of SubRow, Files, HoverButtons and other children for non-latest messages. * perf: memoize ChatForm children to prevent streaming re-renders - Wrap StopButton in React.memo - Wrap AudioRecorder in React.memo, use ref for isSubmitting in onTranscriptionComplete callback to stabilize it - Remove useChatContext() from FileFormChat (bypassed its memo during streaming), accept files/setFiles/setFilesLoading as props from ChatForm instead * perf: stabilize ChatForm child props to prevent cascading re-renders ChatForm re-renders frequently during streaming (ChatContext changes). This caused StopButton and AttachFileChat/AttachFileMenu to re-render despite being memo'd, because their props were new references each time. - Wrap handleStopGenerating in a ref-based stable callback so StopButton always receives the same function reference - Create stableConversation via useMemo keyed on rendering-relevant fields only (conversationId, endpoint, agent_id, etc.), so AttachFileChat and FileFormChat don't re-render from unrelated conversation metadata updates (e.g., title generation) * perf: remove ChatContext subscription from AttachFileMenu and FileFormChat Both components used useFileHandling() which internally calls useChatContext(), bypassing their React.memo wrappers and causing re-renders on every streaming chunk. Switch to useFileHandlingNoChatContext() which accepts file state as parameters. The state (files, setFiles, setFilesLoading, conversation) is passed down from ChatForm → AttachFileChat → AttachFileMenu as props, keeping the memo chain intact. * fix: update imports and test mocks for useFileHandlingNoChatContext - Re-export useFileHandlingNoChatContext from hooks barrel - Import from ~/hooks instead of direct path for test compatibility - Add useToastContext mock to @librechat/client in AttachFileMenu tests since useFileHandlingNoChatContext runs the core hook which needs it - Add useFileHandlingNoChatContext to ~/hooks test mock * perf: fix remaining ChatForm streaming re-renders - Switch AttachFileMenu from useSharePointFileHandling (subscribes to ChatContext) to useSharePointFileHandlingNoChatContext with explicit file state props - Memoize ChatForm textarea onFocus/onBlur handlers with useCallback to prevent TextareaAutosize re-renders (inline arrow functions and .bind() created new references on every ChatForm render) - Update AttachFileMenu test mocks for new hook variants * refactor: add displayName to ChatForm for React DevTools * perf: prevent ChatForm re-renders during streaming via wrapper pattern ChatForm was re-rendering on every streaming chunk because it subscribed to useChatContext() internally, and the ChatContext value changed frequently during streaming. Extract context subscription into a ChatFormWrapper that: - Subscribes to useChatContext() (re-renders on every chunk, cheap) - Stabilizes conversation via selective useMemo - Stabilizes handleStopGenerating via ref-based callback - Passes individual stable values as props to ChatForm ChatForm (memo'd) now receives context values as props instead of subscribing directly. Since individual values (files, setFiles, isSubmitting, etc.) are stable references during streaming, ChatForm's memo prevents re-renders entirely — it only re-renders when isSubmitting actually toggles (2x per stream: start/end). * perf: stabilize newConversation prop and memoize CollapseChat - Wrap newConversation in ref-based stable callback in ChatFormWrapper (was the remaining unstable prop causing ChatForm to re-render) - Wrap CollapseChat in React.memo to prevent re-renders from parent * perf: memoize useAddedResponse return value useAddedResponse returned a new object literal on every render, causing AddedChatContext.Provider to trigger re-renders of all consumers (including ChatForm) on every streaming chunk. Wrap in useMemo so the context value stays referentially stable. * perf: memoize TextareaHeader to prevent re-renders from ChatForm * perf: address review findings for streaming render optimization Finding 1: Switch AttachFile.tsx from useFileHandling to useFileHandlingNoChatContext, closing the optimization hole for standard (non-agent) chat endpoints. Finding 2: Replace content reference equality with length comparison in both memo comparators — safer against buildTree array reconstruction. Finding 3: Add conversation?.model to stableConversation deps in ChatFormWrapper so file uploads use the correct model after switches. Finding 4/14: Fix stableNewConversation to explicitly return the underlying call's result instead of discarding it via `as` cast. Finding 5/6: Extract useMemoizedChatContext hook shared by Message.tsx and MessageContent.tsx — eliminates ~70 lines of duplication and stabilizes chatContext.conversation via selective useMemo to prevent post-stream metadata updates from re-rendering all messages. Finding 8: Use TMessage type for regenerate param instead of Record<string, unknown>. Finding 9: Use FileSetter alias in FileFormChat instead of inline type. Finding 11: Fix pre-existing broken throttle in useMessageProcess — was creating a new throttle instance per call, providing zero deduplication. Now retains the instance via useMemo. Finding 12: Initialize isSubmittingRef with chatContext.isSubmitting instead of false for consistency. Finding 13: Add ChatFormWrapper displayName. * fix: revert content comparison to reference equality in memo comparators The length-based comparison (content?.length) missed updates within existing content parts during streaming — text chunks update a part's content without changing the array length, so the comparator returned true and skipped re-renders for the latest message. Reference equality (===) is correct here: buildTree preserves content array references for unchanged messages via shallow spread, while React Query gives the latest message a new reference when its content updates during streaming. * fix: cancel throttled handleScroll on unmount and remove unused import * fix: use chatContext getter directly in regenerateMessage callback The local isSubmittingRef was stale for non-latest messages (which don't re-render during streaming by design). chatContext.isSubmitting is a getter backed by the wrapper's ref, so reading it at call-time always returns the current value regardless of whether the component has re-rendered. * fix: remove unused useCallback import from useMemoizedChatContext * fix: pass global isSubmitting to HoverButtons for action gating HoverButtons uses isSubmitting via useGenerationsByLatest to disable regenerate and hide edit buttons during streaming. Passing the effective value (false for non-latest messages) re-enabled those actions mid-stream, risking overlapping edits/regenerations. Use chatContext.isSubmitting (getter, always returns current value) for HoverButtons while keeping the effective value for rendering-only UI (cursor, placeholder, streaming indicator). * fix: address second review — stale HoverButtons, messages dep, cleanup - Add isSubmitting to chatContext useMemo deps in useMemoizedChatContext so HoverButtons correctly updates when streaming starts/ends (2 extra re-renders per session, belt-and-suspenders for post-stream state) - Change conversation?.messages?.length dep to boolean in ChatFormWrapper stableConversation — only need 0↔1+ transition for landing page check, not exact count on every message addition - Add defensive comment at chatContext destructuring point in useMessageActions explaining why isSubmitting must not be destructured - Remove dead mockUseFileHandling.mockReturnValue from AttachFileMenu tests * chore: remove dead useFileHandling mock artifacts from AttachFileMenu tests * fix: resolve eslint warnings for useMemo dependencies - Extract complex expression (conversation?.messages?.length ?? 0) > 0 to hasMessages variable for static analysis in ChatFormWrapper - Add eslint-disable for intentional isSubmitting dep in useMemoizedChatContext (forces new chatContext reference on streaming start/end so HoverButtons re-renders)
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…danny-avila#12454) * refactor: add TMessageChatContext type for stable context passing Defines a type for a stable context object that wrapper components pass to memo'd message components, avoiding direct ChatContext subscriptions that bypass React.memo during streaming. * perf: remove ChatContext subscription from useMessageActions useMessageActions previously called useChatContext() inside memo'd components (MessageRender, ContentRender), bypassing React.memo when isSubmitting changed during streaming. Now accepts a stable chatContext param instead, using a ref for the isSubmitting guard in regenerateMessage. Also stabilizes handleScroll in useMessageProcess by using a ref for isSubmitting instead of including it in useCallback deps. * perf: pass stable chatContext to memo'd message components Wrapper components (Message, MessageContent) now create a stable chatContext object via useMemo with a getter-backed isSubmitting, and compute effectiveIsSubmitting (false for non-latest messages). This ensures MessageRender and ContentRender (both React.memo'd) only re-render for the latest message during streaming, preventing unnecessary re-renders of all prior messages and their SubRow, HoverButtons, and SiblingSwitch children. * perf: add custom memo comparators to prevent message reference re-renders buildTree creates new message objects on every streaming update for ALL messages, not just the changed one. This defeats React.memo's default shallow comparison since the message prop has a new reference even when the content hasn't changed. Custom areEqual comparators now compare message by key fields (messageId, text, error, depth, children length, etc.) instead of reference equality, preventing unnecessary re-renders of SubRow, Files, HoverButtons and other children for non-latest messages. * perf: memoize ChatForm children to prevent streaming re-renders - Wrap StopButton in React.memo - Wrap AudioRecorder in React.memo, use ref for isSubmitting in onTranscriptionComplete callback to stabilize it - Remove useChatContext() from FileFormChat (bypassed its memo during streaming), accept files/setFiles/setFilesLoading as props from ChatForm instead * perf: stabilize ChatForm child props to prevent cascading re-renders ChatForm re-renders frequently during streaming (ChatContext changes). This caused StopButton and AttachFileChat/AttachFileMenu to re-render despite being memo'd, because their props were new references each time. - Wrap handleStopGenerating in a ref-based stable callback so StopButton always receives the same function reference - Create stableConversation via useMemo keyed on rendering-relevant fields only (conversationId, endpoint, agent_id, etc.), so AttachFileChat and FileFormChat don't re-render from unrelated conversation metadata updates (e.g., title generation) * perf: remove ChatContext subscription from AttachFileMenu and FileFormChat Both components used useFileHandling() which internally calls useChatContext(), bypassing their React.memo wrappers and causing re-renders on every streaming chunk. Switch to useFileHandlingNoChatContext() which accepts file state as parameters. The state (files, setFiles, setFilesLoading, conversation) is passed down from ChatForm → AttachFileChat → AttachFileMenu as props, keeping the memo chain intact. * fix: update imports and test mocks for useFileHandlingNoChatContext - Re-export useFileHandlingNoChatContext from hooks barrel - Import from ~/hooks instead of direct path for test compatibility - Add useToastContext mock to @librechat/client in AttachFileMenu tests since useFileHandlingNoChatContext runs the core hook which needs it - Add useFileHandlingNoChatContext to ~/hooks test mock * perf: fix remaining ChatForm streaming re-renders - Switch AttachFileMenu from useSharePointFileHandling (subscribes to ChatContext) to useSharePointFileHandlingNoChatContext with explicit file state props - Memoize ChatForm textarea onFocus/onBlur handlers with useCallback to prevent TextareaAutosize re-renders (inline arrow functions and .bind() created new references on every ChatForm render) - Update AttachFileMenu test mocks for new hook variants * refactor: add displayName to ChatForm for React DevTools * perf: prevent ChatForm re-renders during streaming via wrapper pattern ChatForm was re-rendering on every streaming chunk because it subscribed to useChatContext() internally, and the ChatContext value changed frequently during streaming. Extract context subscription into a ChatFormWrapper that: - Subscribes to useChatContext() (re-renders on every chunk, cheap) - Stabilizes conversation via selective useMemo - Stabilizes handleStopGenerating via ref-based callback - Passes individual stable values as props to ChatForm ChatForm (memo'd) now receives context values as props instead of subscribing directly. Since individual values (files, setFiles, isSubmitting, etc.) are stable references during streaming, ChatForm's memo prevents re-renders entirely — it only re-renders when isSubmitting actually toggles (2x per stream: start/end). * perf: stabilize newConversation prop and memoize CollapseChat - Wrap newConversation in ref-based stable callback in ChatFormWrapper (was the remaining unstable prop causing ChatForm to re-render) - Wrap CollapseChat in React.memo to prevent re-renders from parent * perf: memoize useAddedResponse return value useAddedResponse returned a new object literal on every render, causing AddedChatContext.Provider to trigger re-renders of all consumers (including ChatForm) on every streaming chunk. Wrap in useMemo so the context value stays referentially stable. * perf: memoize TextareaHeader to prevent re-renders from ChatForm * perf: address review findings for streaming render optimization Finding 1: Switch AttachFile.tsx from useFileHandling to useFileHandlingNoChatContext, closing the optimization hole for standard (non-agent) chat endpoints. Finding 2: Replace content reference equality with length comparison in both memo comparators — safer against buildTree array reconstruction. Finding 3: Add conversation?.model to stableConversation deps in ChatFormWrapper so file uploads use the correct model after switches. Finding 4/14: Fix stableNewConversation to explicitly return the underlying call's result instead of discarding it via `as` cast. Finding 5/6: Extract useMemoizedChatContext hook shared by Message.tsx and MessageContent.tsx — eliminates ~70 lines of duplication and stabilizes chatContext.conversation via selective useMemo to prevent post-stream metadata updates from re-rendering all messages. Finding 8: Use TMessage type for regenerate param instead of Record<string, unknown>. Finding 9: Use FileSetter alias in FileFormChat instead of inline type. Finding 11: Fix pre-existing broken throttle in useMessageProcess — was creating a new throttle instance per call, providing zero deduplication. Now retains the instance via useMemo. Finding 12: Initialize isSubmittingRef with chatContext.isSubmitting instead of false for consistency. Finding 13: Add ChatFormWrapper displayName. * fix: revert content comparison to reference equality in memo comparators The length-based comparison (content?.length) missed updates within existing content parts during streaming — text chunks update a part's content without changing the array length, so the comparator returned true and skipped re-renders for the latest message. Reference equality (===) is correct here: buildTree preserves content array references for unchanged messages via shallow spread, while React Query gives the latest message a new reference when its content updates during streaming. * fix: cancel throttled handleScroll on unmount and remove unused import * fix: use chatContext getter directly in regenerateMessage callback The local isSubmittingRef was stale for non-latest messages (which don't re-render during streaming by design). chatContext.isSubmitting is a getter backed by the wrapper's ref, so reading it at call-time always returns the current value regardless of whether the component has re-rendered. * fix: remove unused useCallback import from useMemoizedChatContext * fix: pass global isSubmitting to HoverButtons for action gating HoverButtons uses isSubmitting via useGenerationsByLatest to disable regenerate and hide edit buttons during streaming. Passing the effective value (false for non-latest messages) re-enabled those actions mid-stream, risking overlapping edits/regenerations. Use chatContext.isSubmitting (getter, always returns current value) for HoverButtons while keeping the effective value for rendering-only UI (cursor, placeholder, streaming indicator). * fix: address second review — stale HoverButtons, messages dep, cleanup - Add isSubmitting to chatContext useMemo deps in useMemoizedChatContext so HoverButtons correctly updates when streaming starts/ends (2 extra re-renders per session, belt-and-suspenders for post-stream state) - Change conversation?.messages?.length dep to boolean in ChatFormWrapper stableConversation — only need 0↔1+ transition for landing page check, not exact count on every message addition - Add defensive comment at chatContext destructuring point in useMessageActions explaining why isSubmitting must not be destructured - Remove dead mockUseFileHandling.mockReturnValue from AttachFileMenu tests * chore: remove dead useFileHandling mock artifacts from AttachFileMenu tests * fix: resolve eslint warnings for useMemo dependencies - Extract complex expression (conversation?.messages?.length ?? 0) > 0 to hasMessages variable for static analysis in ChatFormWrapper - Add eslint-disable for intentional isSubmitting dep in useMemoizedChatContext (forces new chatContext reference on streaming start/end so HoverButtons re-renders)
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Summary
I systematically eliminated cascading re-renders during message streaming across the message list and chat input areas. The core problem was that
useChatContext()subscriptions insideReact.memo'd components bypassed memoization — whenisSubmittingor other ChatContext values changed during streaming, every component subscribing to the context re-rendered regardless of memo wrappers. The same pattern repeated withuseFileHandling()and unmemoized return values from hooks likeuseAddedResponse().TMessageChatContexttype and a stable context object pattern usinguseMemowith a getter-backedisSubmitting(ref-based) so the object reference stays stable across streaming updates while callbacks can still read the current value at call-time.useChatContext()fromuseMessageActions— accept a stablechatContextparameter instead, preventing context-triggered re-renders that bypassReact.memoonMessageRenderandContentRender.handleScrollinuseMessageProcessby using a ref forisSubmittinginstead of including it inuseCallbackdeps.areEqualcomparators toMessageRenderandContentRendermemo wrappers that compare themessageprop by key fields (messageId,text,depth,children.length, etc.) instead of reference equality, sincebuildTreecreates new objects for all messages on every streaming chunk.effectiveIsSubmittingcomputation (false for non-latest messages) into theMessageandMessageContentwrapper components so non-latest messages receive a stablefalseprop.StopButton,AudioRecorder,CollapseChat, andTextareaHeaderinReact.memo.useChatContext()fromFileFormChatandAttachFileMenuby switching to the existinguseFileHandlingNoChatContextanduseSharePointFileHandlingNoChatContextvariants, passing file state as explicit props fromChatForm.handleStopGeneratingandnewConversationinChatFormWrappervia ref-based callbacks soStopButtonandMentionreceive stable function references.stableConversationvia selectiveuseMemoinChatFormWrapperkeyed on rendering-relevant fields only, preventing re-renders from unrelated conversation metadata updates like title generation.useChatContext()subscription fromChatForminto aChatFormWrapperthat passes individual stable values as props, allowingChatForm's memo to actually prevent re-renders.useAddedResponsereturn value — it was returning a raw object literal on every render, causingAddedChatContext.Providerto trigger all consumers on every streaming chunk.useFileHandlingNoChatContextfrom the hooks barrel and update test mocks forAttachFileMenuandAttachFileChat.displayNametoChatFormfor React DevTools visibility.Change Type
Testing
Profile with React DevTools Profiler during active message streaming:
MessageRender/ContentRendercomponents show "Did not render" in the flamegraph.AttachFileMenu,AttachFileChat,StopButton,AudioRecorder,FileFormChat,BadgeRow,SendButtonshow "Did not render" during streaming.ChatFormre-renders are minimal (only onisSubmittingtoggle, not every chunk).Checklist