Bug 111143 – setTimeouts triggered by WebWorker messages are not executed in order

• Component: UI Events
• Status: UNCONFIRMED

[Adam Rice]

Created attachment 190889 [details]
Test case to reproduce; requires my_task2.js

Steps to reproduce:

1. Save the attached files testTimeoutOrdering2.html and my_task2.js somewhere they will be visible via HTTP.
2. Load testTimeoutOrdering2.html via HTTP (or HTTPS).
3. Click on "Start Test".
4. (Optional) Create lots of new tabs, or apply load to the browser by some other means

Expected behaviour:

"last timeout fired" counts up. "timeouts skipped" remains at 0.

Observed behaviour:

"timeouts skipped" becomes non-zero. This means that timeouts which were registered with setTimeout(closeOverTimeoutCount, 0) in the Window context are being executed out-of-order. This is contrary to the HTML5 spec:

http://www.whatwg.org/specs/web-apps/current-work/multipage/timers.html#dom-windowtimers-settimeout

and also contrary to normal behaviour.

Reproduced:
Safari 6.0.2 (8536.27.17): BAD
WebKit nightly 6.0.2 (8536.26.17, 537+): BAD
Chrome 26.0.1410.12: BAD
Firefox 19.0: OK
Opera 12.14 1738: OK
IE 10: BAD (Hard to reproduce; try opening "Print Preview" then closing it again)

This report and the attached test case are based on http://crbug.com/172587 filed by "offler".

[Adam Rice]

Created attachment 190890 [details]
Javascript for the WebWorker used by the test case