Bug 293319 – AbortController.signal.reason is lost after garbage collection

• Component: DOM
• Status: RESOLVED FIXED

Reproduction: Run the code in Safari, and Collect garbage before the setTimeout resolves

(() => {
    const controller = new AbortController();
    controller.abort(new Error("should print this"));

    // Press 'collect garbage' before this setTimeout resolves
    setTimeout(() => {
        console.log(controller.signal.reason);
    }, 1000);
})()

Actual results:

    'undefined' is printed after one second

Expected results:

    The error "should print this" should be printed after one second

Build date and hardware:

    Safari Technology Preview Release 219 (Safari 18.4, WebKit 20622.1.12) on M3 Max macOS 15.3 (24D60)

[Radar WebKit Bug Importer]

<rdar://problem/152111446>

[youenn fablet]

Pull request: https://github.com/WebKit/WebKit/pull/45986

[EWS]

Committed 295688@main (f1292b56a628): <https://commits.webkit.org/295688@main>

Reviewed commits have been landed. Closing PR #45986 and removing active labels.