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
Created attachment 463957 [details] reduced content for WinCairo
(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.
Created attachment 463961 [details] Another test reduction
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).
<rdar://problem/103434293>