669158 - "ASSERTION: How did that happen?" in nsGlobalWindow::ResetTimersForNonBackgroundWindow

Status: VERIFIED FIXED

(Core :: DOM: Core & HTML, defect, P1)

Description

[Jesse Ruderman]

Attachment: testcase (requires popups to be enabled)

The testcase triggers this assertion, usually within a few seconds:

###!!! ASSERTION: How did that happen?: '!IsTimeout(nextTimeout) || timeout->mWhen < nextTimeout->mWhen', file dom/base/nsGlobalWindow.cpp, line 9469

The function containing this assertion was added in bug 647001.

Comment 1

[Jesse Ruderman]

Attachment: stack trace

Comment 2

[Boris Zbarsky [:bzbarsky]]

Taking. 

What's happening here is that the code in ResetTimersForNonBackgroundWindow assumes timers are stored in mWhen order, which is true _except_ in the middle of a timer firing.  In that case, timers that come after it can have an earlier mWhen than the timer, apparently.  That's the case we're hitting here, as far as I can tell: the b2 timer is firing, calls window.close(), that causes a switch back to the original window and an unclamping of some timer, etc.

I'll dig into this a bit more to figure out exactly what's happening and how to fix it.

Comment 3

[Boris Zbarsky [:bzbarsky]]

Attachment: Don't try to unclamp the dummy timeout.

Comment 4

[Boris Zbarsky [:bzbarsky]]

http://hg.mozilla.org/integration/mozilla-inbound/rev/9e84bca4fc42

Comment 5

[Boris Zbarsky [:bzbarsky]]

Comment on attachment 544645 [details] [diff] [review]
Don't try to unclamp the dummy timeout.

Requesting aurora approval for this.  This should be a safe fix; all we're doing is not unclamping timers that we're about to fire anyway, so that the invariants we assume about the sorting of the timer list continue to hold.

Comment 6

[Kyle Huey (Exited; not receiving bugmail, old account, do not use)]

http://hg.mozilla.org/mozilla-central/rev/9e84bca4fc42

Comment 7

[Boris Zbarsky [:bzbarsky]]

http://hg.mozilla.org/releases/mozilla-aurora/rev/091434c8909e

Comment 8

[Trif Andrei-Alin[:AlinT]]

Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:8.0a2) Gecko/20110821 Firefox/8.0a2

I runned the testcase and the results are that when allowing popups, the tab switches to the popup tab,over and over again(i don't know for how long, i only runned it for a few minutes).
Is that the intended behaviour?
Thanks.

Comment 9

[Boris Zbarsky [:bzbarsky]]

Yes, that's the intended behavior given the code in the testcase.

Comment 10

[Trif Andrei-Alin[:AlinT]]

Thanks for the clarification.
Setting resolution to Verified Fixed.