[world-vercel] Propagate cancel from getReadable() to upstream fetch#1801
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[world-vercel] Propagate cancel from getReadable() to upstream fetch#1801VaguelySerious wants to merge 4 commits intostablefrom
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🦋 Changeset detectedLatest commit: 4a98ba5 The changes in this PR will be included in the next version bump. This PR includes changesets to release 18 packages
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🧪 E2E Test Results❌ Some tests failed Summary
❌ Failed Tests▲ Vercel Production (1 failed)astro (1 failed):
Details by Category❌ ▲ Vercel Production
✅ 🪟 Windows
❌ Some E2E test jobs failed:
Check the workflow run for details. |
When a consumer cancels the ReadableStream returned by `readFromStream` (e.g. an HTTP client hanging up on an endpoint that pipes `run.getReadable()`), the pull loop could continue running and even trigger a fresh reconnect via `connect()` — the new fetch was never tied to the cancellation, so the request kept running in the background. Fix: - Track a `cancelled` flag that `pull` checks before and after each read and before each reconnect. - Plumb an `AbortController.signal` into `fetch` so the in-flight upstream request (including a pending reconnect) is aborted when the consumer cancels. Regression tests cover the abort-signal contract, the mid-timeout reconnect race, and cancel-during-read. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> Signed-off-by: Peter Wielander <mittgfu@gmail.com>
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Signed-off-by: Peter Wielander <mittgfu@gmail.com>
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When a consumer cancels the ReadableStream returned by streams.get (e.g. an HTTP client hanging up on an endpoint that pipes `run.getReadable()`), the pull loop could continue running and even trigger a fresh reconnect via `connect()` — the new fetch was never tied to the cancellation, so the request kept running in the background. Fix: - Track a `cancelled` flag that `pull` checks before and after each read and before each reconnect. - Plumb an `AbortController.signal` into `fetch` so the in-flight upstream request (including a pending reconnect) is aborted when the consumer cancels. Regression tests cover the abort-signal contract, the mid-timeout reconnect race, and cancel-during-read. Port of #1801 (targeting `stable`). 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> Signed-off-by: Peter Wielander <mittgfu@gmail.com>
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- Point workflow tarballs at peter/fix-stream-cancel-reconnect branch preview - Log request.signal.aborted in the stream route The companion workflow PR (vercel/workflow#1801) adds cancel propagation to world-vercel readFromStream. World-vercel's cancel handler logs 'Cancelling stream' when hit; combined with the route.ts log, we can trace whether the cancel makes it all the way through. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com> Signed-off-by: Peter Wielander <mittgfu@gmail.com>
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Summary
Fixes a regression from #1790 / #1742: when a consumer cancels the
ReadableStreamreturned byrun.getReadable()(e.g. an HTTP client disconnects from an API route that pipes the stream out), the pull loop inreadFromStreamkept running and could trigger further reconnects in the background. The in-flight upstream fetch was never aborted, so the endpoint kept fetching long after the client had gone away.Root cause
Two things combined:
cancelledflag —pullhad no way to know the consumer asked to stop.AbortSignalon the upstreamfetch()— even if we noticed, there was no way to unblock a pending request.The
cancelhandler only calledreader.cancel()on whichever reader was captured at that moment. Ifpullwas mid-reconnect (reader = await connect()),cancelcancelled the stale reader; the new fetch then connected and kept streaming.Fix
cancelledflag thatpullchecks before and after eachreader.read()and before eachconnect().AbortController.signalintofetch, aborted fromcancel, so the in-flight request (including a pending reconnect) unblocks.connect()failures triggered by abort are swallowed silently whencancelled.Tests
Three new tests under `readFromStream reconnection > consumer cancel`:
All 70 world-vercel tests pass.
Note
The same bug exists on `main` (the original #1742 implementation that `main` carries). Will open a separate PR for that once this lands.
Test plan
🤖 Generated with Claude Code