fix(react): refresh transport across renders in useChat#16326
Closed
fayonation wants to merge 3 commits into
Closed
fix(react): refresh transport across renders in useChat#16326fayonation wants to merge 3 commits into
fayonation wants to merge 3 commits into
Conversation
Delegate sendMessages and reconnectToStream through a stable transport ref so inline DefaultChatTransport body/headers stay in sync with React state across re-renders and async initialization. Fixes vercel#7819 Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
5 tasks
pull Bot
pushed a commit
to ben-vargas/ai
that referenced
this pull request
Jul 1, 2026
…one (vercel#16546) ## Background `useChat()` creates its `Chat` instance once and stores it in a `useRef()`, so as a result, a `transport` passed to `useChat()` was captured and then frozen at its value in the first render. If react state later changes, the `transport` becomes stale. A very similar problem was addressed in vercel#8985 but with callbacks. ## Summary Rather than passing the transport directly to `Chat`, this passes a proxy object that always reads the latest transport (or falls back to a default one). This uses the same solution as in vercel#8985 for callbacks. ## Manual Verification Added a route to the ai-e2e-next example at `/chat/stale-transport-demo`. It reproduces the bug without the changes made, and then is fixed with these changes. ## Related Issues Fixes vercel#7819 Closes vercel#12330 Closes vercel#13464 Closes vercel#15380 Closes vercel#16326
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
transportin a ref updated on every renderChata stable delegating transport sosendMessages/reconnectToStreamalways use the latest inlineDefaultChatTransport(and itsbody/headersclosures)transport#bodyis always stale #7819) and asyncuseEffectinitialization (useChatDefaultChatTransportbody does not update when body changes beforesendMessageis called. #7109)Fixes #7819
Test plan
cd packages/react && pnpm build(DTS passes)cd packages/react && pnpm test -- src/use-chat.ui.test.tsx(64 tests)use-chat.ts)