571105 - "ASSERTION: Visited style has wrong parent" with <link> root

Status: RESOLVED FIXED

(Core :: Layout, defect)

Description

[Jesse Ruderman]

Attachment: testcase

###!!! ASSERTION: Visited style has wrong parent: 'Error', file /builds/moz2_slave/mozilla-central-macosx-debug/build/layout/base/nsFrameManager.cpp, line 638
frame: ScrollbarFrame(scrollbar)(-1) (0x3b3bb70) style: 0x3b3a9d8 {}

This assertion was added in a patch in bug 558943.

Comment 1

[Boris Zbarsky [:bzbarsky]]

So in this case aContext->GetParent()->GetStyleIfVisited() is null, but "childStyleIfVisited->GetRuleNode() == aContext->GetRuleNode()" is true.

The frame in question is the scrollbar frame.  The root scrollbar, of course.

Now the scrollbar's style context is parented to the scrollframe's style context.  The scrollframe's style context does NOT have a style if visited.  But the scrollbar does.  At the same time, the scrollbar's style context and its style if visited have the _same_ rulenode.

Should we perhaps treat aVisitedRuleNode == aRuleNode as being equivalent to aVisitedRuleNode == null in GetContext?

Comment 2

[Boris Zbarsky [:bzbarsky]]

In particular, in this case it seems like we had a relevant link, but no difference in the rules that actually matched us with :visited vs not.

If we make the change I suggest in comment 1, we can remove the code in ReparentStyleContext that was doing that already.

Comment 3

[Boris Zbarsky [:bzbarsky]]

Attachment: Like so, perhaps

Comment 4

[Boris Zbarsky [:bzbarsky]]

Er, I added the testcase as a crashtest locally.

Comment 5

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Comment on attachment 450729 [details] [diff] [review]
Like so, perhaps

r=dbaron

Comment 6

[Boris Zbarsky [:bzbarsky]]

Pushed http://hg.mozilla.org/mozilla-central/rev/b0e7db4a20c7