[wrangler] Keep request-scoped proxy errors non-fatal - #15207
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The e2e job died mid-run and passed on a re-run. It was not flaky infrastructure and it was not the OOM killer: `wrangler dev` exits on a SINGLE failed proxied request, and reports it as `✘ [ERROR]` with an empty message. Wrangler forwards every request through its own ProxyWorker. When that inner fetch rejects, the ProxyWorker reports it to the ProxyController, `DevEnv.handleErrorEvent` finds no matching non-fatal case and re-emits it as a top-level `error`; the dev command is `await events.once(devEnv, "teardown")`, and Node's `events.once` rejects on `error`, so the command throws and the process exits 1. The cause crossed a Worker boundary, so it is a plain object rather than an Error, and `castErrorCause` wraps it in `new Error()` -- message "". Hence a fatal exit that names nothing. The rejection is `Network connection lost.`, raised when a client disconnects while its request body is still uploading. Playwright does that every time it closes a page with a form POST in flight. Confirmed by reduction: five aborted uploads against a bare Worker kill wrangler 4.121.0 with the exact CI signature, and survive it patched. So the failure was one browser-side race taking down the server for the rest of the suite -- seventy `ERR_CONNECTION_REFUSED` failures, three attempts each, none of them naming the event. Patch wrangler with upstream's own fix (cloudflare/workers-sdk#15207, issue #15203): report the failed request and keep serving. Two call sites, because wrangler bundles the ProxyController twice. Remove the patch when a release carries the fix -- a version bump that leaves it here fails the install rather than applying quietly. `patches/**` joins the js paths filter: a patched dependency is application behaviour, and editing it must run the suite that proves it. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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The e2e job died mid-run and passed on a re-run. It was not flaky infrastructure and it was not the OOM killer: `wrangler dev` exits on a SINGLE failed proxied request, and reports it as `✘ [ERROR]` with an empty message. Wrangler forwards every request through its own ProxyWorker. When that inner fetch rejects, the ProxyWorker reports it to the ProxyController, `DevEnv.handleErrorEvent` finds no matching non-fatal case and re-emits it as a top-level `error`; the dev command is `await events.once(devEnv, "teardown")`, and Node's `events.once` rejects on `error`, so the command throws and the process exits 1. The cause crossed a Worker boundary, so it is a plain object rather than an Error, and `castErrorCause` wraps it in `new Error()` -- message "". Hence a fatal exit that names nothing. The rejection is `Network connection lost.`, raised when a client disconnects while its request body is still uploading. Playwright does that every time it closes a page with a form POST in flight. Confirmed by reduction: five aborted uploads against a bare Worker kill wrangler 4.121.0 with the exact CI signature, and survive it patched. So the failure was one browser-side race taking down the server for the rest of the suite -- seventy `ERR_CONNECTION_REFUSED` failures, three attempts each, none of them naming the event. Patch wrangler with upstream's own fix (cloudflare/workers-sdk#15207, issue #15203): report the failed request and keep serving. Two call sites, because wrangler bundles the ProxyController twice. Remove the patch when a release carries the fix -- a version bump that leaves it here fails the install rather than applying quietly. `patches/**` joins the js paths filter: a patched dependency is application behaviour, and editing it must run the suite that proves it. Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
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+💯 priority to fix. This is blocking us in development. In the meantime, we're using the patch. |
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Fixes #15203.
Refs #14926 and #14641.
Customer Summary
wrangler devrunning when proxying one local request fails, instead of terminating the development session and its dependent test runner.Network connection lost.) rather than an empty fatal diagnostic.Technical Summary
ProxyWorkerfetch errors as request-scoped failures and logs them without dispatching a fatal controllererrorevent.Why
ProxyWorkeralready rejects the affected request. Promoting its serialized error to the dev environment's fatal error bus unnecessarily shuts downwrangler dev, which then causes parallel Playwright processes to receive SIGTERM.Testing
pnpm -w test:ci -F wrangler -- ProxyController.test.tspnpm prettifypnpm check(203 tasks passed)Network connection lost.A picture of a cute animal (not mandatory, but encouraged)