Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 8490d02c5dcc8461ce5d8161717d292d8085a596
https://github.com/WebKit/WebKit/commit/8490d02c5dcc8461ce5d8161717d292d8085a596
Author: Sosuke Suzuki <[email protected]>
Date: 2026-07-12 (Sun, 12 Jul 2026)
Changed paths:
A
JSTests/stress/async-from-sync-iterator-close-on-rejection-throwing-return.js
M Source/JavaScriptCore/runtime/JSMicrotask.cpp
Log Message:
-----------
[JSC] AsyncFromSyncIterator does not close correctly when the sync iterator
yields a rejected value promise
https://bugs.webkit.org/show_bug.cgi?id=319185
Reviewed by Yusuke Suzuki.
Per IteratorClose[1] invoked with a throw completion, any exception thrown
while getting or calling the return method must be discarded so the outer
completion (the original rejection reason) is preserved. JSC was letting a
throwing return() propagate (leaving the promise pending with an uncaught
exception) and letting a throwing return getter reject the promise with the
getter's exception instead of the original reason.
const it = {
[Symbol.iterator]: () => ({
next: () => ({ value: Promise.reject(new Error("original")), done:
false }),
return() { throw new Error("close error"); }
})
};
(async () => { for await (const _ of it) {} })(); // never settled before
[1]: https://tc39.es/ecma262/#sec-iteratorclose
Test:
JSTests/stress/async-from-sync-iterator-close-on-rejection-throwing-return.js
*
JSTests/stress/async-from-sync-iterator-close-on-rejection-throwing-return.js:
Added.
(shouldBe):
(const.syncIterable.Symbol.iterator.return.get return):
(throw.new.Error.async drainMicrotasks):
(async drainMicrotasks):
(async gen):
(throw.new.Error):
* Source/JavaScriptCore/runtime/JSMicrotask.cpp:
(JSC::asyncFromSyncIteratorContinueOrDone):
Canonical link: https://commits.webkit.org/317012@main
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