513146 - mochitest-plain: test_domWindowUtils.html fails intermittently

Status: RESOLVED FIXED

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

Description

[Serge Gautherie (:sgautherie)]

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox3.5/1251411556.1251418059.10690.gz
Linux mozilla-1.9.1 unit test on 2009/08/27 15:19:16
{
... | at index 0 for data [0, 100] - got null, expected [object HTMLDivElement]
... | at index 1 for data [9, 109] - got null, expected [object HTMLDivElement]
... | at index 4 for data [0, 100, true, false] - got null, expected [object HTMLDivElement]
... | at index 5 for data [9, 109, true, false] - got null, expected [object HTMLDivElement]
... | at index 6 for data [0, 100000, true, false] - got null, expected [object HTMLDivElement]
... | at index 7 for data [9, 100009, true, false] - got null, expected [object HTMLDivElement]
}

Comment 1

[David Dahl :ddahl]

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox3.5-Unittest/1252094822.1252096869.8026.gz&fulltext=1

Comment 2

[Daniel Holbert [:dholbert]]

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox3.5-Unittest/1257186501.1257188837.6044.gz
Linux mozilla-1.9.1 test mochitests on 2009/11/02 10:28:21

Comment 3

[Boris Zbarsky [:bzbarsky]]

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1266601481.1266602103.10239.gz
OS X 10.5.2 mozilla-central opt test mochitests-3/5 on 2010/02/19 09:44:41  
s: bm-xserve17

Comment 4

[Boris Zbarsky [:bzbarsky]]

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1266602287.1266604723.18310.gz
WINNT 5.2 mozilla-central debug test mochitests-3/5 on 2010/02/19 09:58:07  
s: win32-slave18

Comment 5

[David Dahl :ddahl]

OS X 10.5.2 mozilla-central opt test mochitests-3/5 [testfailed] Started 11:23, finished 11:36
http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1266607388.1266608141.31755.gz

Comment 6

[David Dahl :ddahl]

Linux mozilla-central opt test mochitests-3/5 [testfailed] Started 11:29, finished 11:47
http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1266607768.1266608765.1650.gz

Comment 7

[David Dahl :ddahl]

OS X 10.5.2 mozilla-central opt test mochitests-3/5 [testfailed] Started 11:56, finished 12:12

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1266609416.1266610318.6170.gz

Comment 8

[David Dahl :ddahl]

WINNT 5.2 mozilla-central opt test mochitests-3/5 [testfailed] Started 12:09, finished 12:21
http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1266601481.1266602103.10239.gz

Comment 9

[David Dahl :ddahl]

WINNT 5.2 mozilla-central debug test mochitests-3/5 [testfailed] Started 13:56, finished 14:34
http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1266616575.1266618835.2312.gz

Comment 10

[David Dahl :ddahl]

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1266617159.1266619251.3656.gz

WINNT 5.2 mozilla-central debug test mochitests-3/5 [testfailed] Started 14:05, finished 14:41

Comment 11

[David Dahl :ddahl]

OS X 10.5.2 mozilla-central opt test mochitests-3/5 [testfailed] Started 14:44, finished 14:53

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1266619455.1266619967.6279.gz

Comment 12

[David Dahl :ddahl]

OS X 10.5.2 mozilla-central opt test mochitests-3/5 [testfailed] Started 17:48, finished 17:58

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1266630528.1266631064.8888.gz

Comment 13

[Daniel Holbert [:dholbert]]

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1266631570.1266632012.11393.gz
Linux mozilla-central opt test mochitests-3/5 on 2010/02/19 18:06:10
s: moz2-linux-slave21

Comment 14

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

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1266632216.1266633906.16976.gz

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1266632330.1266632846.13939.gz

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1266633154.1266633623.16243.gz

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1266614437.1266617673.30749.gz

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1266621502.1266621912.13635.gz

This is permaorange on Windows.

Comment 15

[Boris Zbarsky [:bzbarsky]]

Attachment: The fix I just pushed [Checkin: Comment 16+18 & 19 & 20]

This test went perma-orange today when I checked in reflows off refresh driver.

The reason for this (and for the previous failures) is that the test structure is basically like this:

  <link rel="stylesheet" href="something">
  <!-- some other stuff -->
  <div style="position it somewhere">
  <script>
    function f() {
      // rely on the div being positioned at the right somewhere without
      // flushing layout first
    }
    f();
  </script>

If the script runs before the <div> has been initially laid out, the test fails.  The only reason it sometimes passed before is that we sometimes parsed the <div> before the stylesheet had finished loading.  When we then parsed the <script>, it blocked on the stylesheet load, went back out to the event loop, and we processed the div layout before the script executed.  If the race went the other way, so the sheet loaded before we parsed the <div>, then the test failed.

With reflow off refresh driver, we started failing unless we ended up hanging out in the event loop waiting for the sheet load for more than 20ms or so.  Which was most of the time.

The fix is simple: just don't run the test function until onload, at which point the layout should be up-to-date.  The other option (which doesn't rely on that onload behavior, in case we ever want to switch to the cheating Webkit way) is an explicit flush at the start of the test function.  Gavin, let me know if you'd prefer that.

Comment 16

[Serge Gautherie (:sgautherie)]

(In reply to comment #15)
> Created an attachment (id=427903) [details]
> The fix I just pushed

http://hg.mozilla.org/mozilla-central/rev/1d2b78587a8a

Comment 17

[:Gavin Sharp [email: [e-mail]]]

Comment on attachment 427903 [details] [diff] [review]
The fix I just pushed
[Checkin: Comment 16+18 & 19 & 20]

A comment explaining why we're waiting for onload might not hurt, but I think this is fine.

Comment 18

[Boris Zbarsky [:bzbarsky]]

Pushed a comment as http://hg.mozilla.org/mozilla-central/rev/975a17a14ec7

Comment 19

[Serge Gautherie (:sgautherie)]

Comment on attachment 427903 [details] [diff] [review]
The fix I just pushed
[Checkin: Comment 16+18 & 19 & 20]


http://hg.mozilla.org/releases/mozilla-1.9.2/rev/6315d8b83a54

Comment 20

[Serge Gautherie (:sgautherie)]

Comment on attachment 427903 [details] [diff] [review]
The fix I just pushed
[Checkin: Comment 16+18 & 19 & 20]


(In reply to comment #19)
> http://hg.mozilla.org/releases/mozilla-1.9.2/rev/6315d8b83a54

Sorry, I pushed with my name...

***

http://hg.mozilla.org/releases/mozilla-1.9.1/rev/dec3225c7aaf