Bug 132421

Summary: fast/multicol/fixed-stack.html failing since introduction.
Product: WebKit Reporter: Andreas Kling <kling>
Component: Layout and RenderingAssignee: Dave Hyatt <hyatt>
Status: NEW ---    
Severity: Normal CC: ap, bfulgham, clopez, darin, kling, simon.fraser, thorton
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
See Also: https://bugs.webkit.org/show_bug.cgi?id=159214
Attachments:
Description Flags
Patch darin: review+

Description Andreas Kling 2014-05-01 00:15:05 PDT
This test was added in r168076 and is failing on bots since.

It appears to be a problem with compositing vs non-compositing code paths. There is a small antialiasing difference in the output, and it goes away if I force the -expected.html to use accelerate compositing as well.
Comment 1 Andreas Kling 2014-05-01 00:18:44 PDT
Skipped: <http://trac.webkit.org/changeset/168090>
Comment 2 Tim Horton 2014-05-01 06:54:31 PDT
Seems like this should have gotten ImageOnlyFailure'd, not Skipped! That way we'll still learn if the text parts differ and just ignore the bad image parts.
Comment 3 Dave Hyatt 2014-05-01 09:41:47 PDT
Hmmm not sure how to fix. The whole point was to compare compositing vs. non-compositing, so if the images aren't going to match I'm not sure how to test this issue.
Comment 4 Dave Hyatt 2014-05-01 09:42:06 PDT
I guess I should turn it into a pixel test.
Comment 5 Alexey Proskuryakov 2014-05-01 09:43:23 PDT
Updated the expectation in <http://trac.webkit.org/r168106>.
Comment 6 Tim Horton 2014-05-01 09:49:55 PDT
(In reply to comment #3)
> Hmmm not sure how to fix. The whole point was to compare compositing vs. non-compositing, so if the images aren't going to match I'm not sure how to test this issue.

It would be nice to have a link to the failure here so we can see what kind of AA differences are occuring. Ideally there should be no differences between the two modes, and you shouldn't have to worry about this when writing a test.

Andreas, did it fail on WebKit2 bots as well? (i.e. was the issue with the whole webview being in compositing/not, which only switches on WebKit1 bots, or with the content specifically being in compositing/not, which switches on both).
Comment 8 Carlos Alberto Lopez Perez 2014-08-19 04:36:59 PDT
This test pass on GTK (WK2)
Comment 9 Alexey Proskuryakov 2014-10-24 12:12:05 PDT
As of Yosemite, the test now fails on WK1 too, because it actually started to use compositing.

Updated expectations in <http://trac.webkit.org/r175170>.
Comment 10 Brent Fulgham 2015-01-21 14:20:04 PST
(In reply to comment #9)
> As of Yosemite, the test now fails on WK1 too, because it actually started
> to use compositing.
> 
> Updated expectations in <http://trac.webkit.org/r175170>.

After this test expectation change, Windows now passes as well.
Comment 11 Simon Fraser (smfr) 2021-12-21 20:51:31 PST
Created attachment 447777 [details]
Patch