Bug 249010 – SHOULD NEVER BE REACHED in Layout::TextUtil::breakWord

• Component: Layout and Rendering
• Status: NEW

[Fujii Hironori]

SHOULD NEVER BE REACHED in Layout::TextUtil::breakWord

WinCairo Debug (257609@main) hits an assertion failure by loading https://b.hatena.ne.jp/ .

SHOULD NEVER BE REACHED
C:\home\webkit\gc\Source\WebCore\layout/formattingContexts/inline/text/TextUtil.cpp(303) : WebCore::Layout::TextUtil::breakWord
1   00007FF8FF28248B WTFCrash
2   00007FF8E481D6BE WTFCrashWithInfo
3   00007FF8E7C69CB7 WebCore::Layout::TextUtil::breakWord
4   00007FF8E7C24748 WebCore::Layout::Line::Run::truncate
5   00007FF8E7C2307D WebCore::Layout::Line::truncate
6   00007FF8E7C7571D `WebCore::Layout::LineBuilder::close'::`2'::<lambda_2>::operator()
7   00007FF8E7C68030 WebCore::Layout::LineBuilder::close
8   00007FF8E7C63C10 WebCore::Layout::LineBuilder::layoutInlineContent
9   00007FF8E7C3AB0B WebCore::Layout::InlineFormattingContext::lineLayout
10  00007FF8E7C3A387 WebCore::Layout::InlineFormattingContext::layoutInFlowContentForIntegration
11  00007FF8E7CE5E07 WebCore::LayoutIntegration::LineLayout::layout
12  00007FF8E866DBE2 WebCore::RenderBlockFlow::layoutModernLines
13  00007FF8E865BA5A WebCore::RenderBlockFlow::layoutInlineChildren
14  00007FF8E865B659 WebCore::RenderBlockFlow::layoutInFlowChildren
15  00007FF8E8659B37 WebCore::RenderBlockFlow::layoutBlock
16  00007FF8E864C09F WebCore::RenderBlock::layout
17  00007FF8E7D1080E WebCore::RenderElement::layoutIfNeeded
18  00007FF8E872A390 WebCore::RenderDeprecatedFlexibleBox::applyModernLineClamp
19  00007FF8E8729691 WebCore::RenderDeprecatedFlexibleBox::applyLineClamp
20  00007FF8E8726F1B WebCore::RenderDeprecatedFlexibleBox::layoutVerticalBox
21  00007FF8E8724CCF WebCore::RenderDeprecatedFlexibleBox::layoutBlock
22  00007FF8E864C09F WebCore::RenderBlock::layout
23  00007FF8E865CBE4 WebCore::RenderBlockFlow::layoutBlockChild
24  00007FF8E865B9B6 WebCore::RenderBlockFlow::layoutBlockChildren
25  00007FF8E865B697 WebCore::RenderBlockFlow::layoutInFlowChildren
26  00007FF8E8659B37 WebCore::RenderBlockFlow::layoutBlock
27  00007FF8E864C09F WebCore::RenderBlock::layout
28  00007FF8E7D1080E WebCore::RenderElement::layoutIfNeeded
29  00007FF8E8731759 WebCore::RenderFlexibleBox::maybeCacheChildMainIntrinsicSize
30  00007FF8E8731220 WebCore::RenderFlexibleBox::computeFlexBaseSizeForChild
31  00007FF8E8734FA7 WebCore::RenderFlexibleBox::constructFlexItem

[Fujii Hironori]

Created attachment 463957 [details]
reduced content for WinCairo

[alan]

(In reply to Fujii Hironori from comment #1)
> Created attachment 463957 [details]
> reduced content
Thank you for the test reduction. I wasn't able to repro the assert with it but surely the page asserts.

[alan]

Created attachment 463961 [details]
Another test reduction

[alan]

This is caused by a shortcut we take in IFC when measuring text based content. It results in a slightly incorrect content width value when runs separated by soft wrap opportunities measure differently than the sum of the run widths individually (ie width("AB") != width("A") + width("B")). In case of "b.hatena.ne.jp" we produce an incorrect rendering but that is addressed here: bug 249030 (and there's no other visual impact AFAICT).

[Radar WebKit Bug Importer]

<rdar://problem/103434293>