1660507 - Cross-origin timeouts/intervals are suspended during sync operations

Status: NEW

(Core :: DOM: Core & HTML, defect)

Description

[u608768]

This came up in bug 1646498 comment 7.

STR

1. Open https://kashav.ca/bugs/1660507/a1.html. Note that the toplevel frame and the innermost frame are same-origin, and that the middle frame is cross-origin. This reproduces regardless of if the frames are same process or not (not a fission bug!).
2. Wait a few seconds for the counters to start.
3. Click either the alert or confirm button in any frame to enter a sync modal operation.
4. In Firefox, you should notice that all 3 counters are paused while a modal is open. Chrome only pauses counters in the same origin as the modal (e.g., opening the modal from the middle frame will not pause the toplevel/innermost counter and similarly for modals opened in the toplevel/innermost frame).

I haven't checked the spec yet, so I'm unsure who is correct here, but figured I'd file this anyways.

Comment 1

[u608768]

Attachment: b.html

Comment 2

[Henri Sivonen (:hsivonen) (temporarily away from Bugzilla)]

Superficially, it looks like we're doing the right thing here. Needinfoing annevk for spec assessment.

Comment 3

[Anne (:annevk)]

Under ideal circumstances the two (theoretical) event loops involved would use separate threads/processes, but the specification allows both Chrome's and Firefox's behavior. See https://html.spec.whatwg.org/#event-loops.