fix: prevent AbortController GC when redirect is 'error' #4750
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When fetch() is called with redirect: 'error', the requestObject could be garbage collected while the fetch was still in progress. This caused the internal AbortController to be collected, which triggered a FinalizationRegistry callback that removed the abort listener from the user's signal, making abort signals ineffective. The fix stores requestObject in fetchParams to keep it alive for the entire duration of the fetch operation. Fixes: #4627 Signed-off-by: Matteo Collina <hello@matteocollina.com>
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #4750 +/- ##
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- Coverage 93.21% 93.21% -0.01%
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Files 109 109
Lines 33982 33989 +7
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+ Hits 31678 31682 +4
- Misses 2304 2307 +3 ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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metcoder95
approved these changes
Jan 22, 2026
Uzlopak
reviewed
Jan 22, 2026
| crossOriginIsolatedCapability | ||
| crossOriginIsolatedCapability, | ||
| // Keep requestObject alive to prevent its AbortController from being GC'd | ||
| // See https://github.com/nodejs/undici/issues/4627 |
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| // See https://github.com/nodejs/undici/issues/4627 |
I would remove this line as it is just a "diary entry". The corresponding test is having the link and is totally fine.
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Summary
Fixes #4627
When
fetch()is called withredirect: 'error', therequestObject(theRequestinstance) could be garbage collected while the fetch was still in progress. TherequestObjectholds an internalAbortControllervia thekAbortControllerproperty. WhenrequestObjectwas GC'd, theAbortControllerwas also collected, triggering aFinalizationRegistrycallback that removed the abort listener from the user's signal. This caused abort signals to have no effect, resulting in connection leaks for SSE streams.Changes
The fix stores a reference to
requestObjectinfetchParams, which stays alive for the entire duration of the fetch operation. This prevents premature garbage collection of therequestObjectand its internalAbortController.requestObjectto thefetching()functionrequestObjectparameter tofetching()function signaturerequestObjectinfetchParamsobjectTest Plan
test/fetch/issue-4627.jsthat requires--expose-gcflagredirect: 'error', triggers GC, aborts, and verifies no data is received after abortabort should work with redirect: error✅abort should work without redirect: error (control test)✅