Bug 143864

Summary: contentWidth can become negative with nested scrollbars
Product: WebKit Reporter: Bem Jones-Bey <bjonesbe>
Component: Layout and RenderingAssignee: Nobody <webkit-unassigned>
Status: NEW ---    
Severity: Normal CC: ahmad.saleem792, rwlbuis, simon.fraser, zalan
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
Test case none

Description Bem Jones-Bey 2015-04-16 22:18:23 PDT 
Created attachment 251004 [details]
Test case

This was originally reported in Blink: https://code.google.com/p/chromium/issues/detail?id=450598

This shows up when a percentage shape margin is specified, since the shape margin is computed based on the width of the containing block, and there's an assert that this computation should always return a positive number,

WebKit stack:
ASSERTION FAILED: shapeMargin() >= 0
/Users/bemjb/Code/WebKit/Source/WebCore/rendering/shapes/RectangleShape.cpp(45) : WebCore::FloatRect WebCore::RectangleShape::shapeMarginBounds() const
1   0x111f23d00 WTFCrash
2   0x114cba5ff WebCore::RectangleShape::shapeMarginBounds() const
3   0x114cbad81 WebCore::RectangleShape::shapeMarginLogicalBoundingBox() const
4   0x1137830dc WebCore::Shape::lineOverlapsShapeMarginBounds(WebCore::LayoutUnit, WebCore::LayoutUnit) const
5   0x1151ca0ac WebCore::ShapeOutsideInfo::computeDeltasForContainingBlockLine(WebCore::RenderBlockFlow const&, WebCore::FloatingObject const&, WebCore::LayoutUnit, WebCore::LayoutUnit)
6   0x1149f74af WebCore::LineWidth::shrinkAvailableWidthForNewFloatIfNeeded(WebCore::FloatingObject*)
7   0x114d23b08 WebCore::RenderBlockFlow::positionNewFloatOnLine(WebCore::FloatingObject*, WebCore::FloatingObject*, WebCore::LineInfo&, WebCore::LineWidth&)
8   0x1149db938 WebCore::LineBreaker::skipLeadingWhitespace(WebCore::BidiResolver<WebCore::InlineIterator, WebCore::BidiRun>&, WebCore::LineInfo&, WebCore::FloatingObject*, WebCore::LineWidth&)
9   0x1149dbb80 WebCore::LineBreaker::nextLineBreak(WebCore::BidiResolver<WebCore::InlineIterator, WebCore::BidiRun>&, WebCore::LineInfo&, WebCore::RenderTextInfo&, WebCore::FloatingObject*, unsigned int, WTF::Vector<WebCore::WordMeasurement, 64ul, WTF::CrashOnOverflow>&)
10  0x114d1e4af WebCore::RenderBlockFlow::layoutRunsAndFloatsInRange(WebCore::LineLayoutState&, WebCore::BidiResolver<WebCore::InlineIterator, WebCore::BidiRun>&, WebCore::InlineIterator const&, WebCore::BidiStatus const&, unsigned int)
11  0x114d1d291 WebCore::RenderBlockFlow::layoutRunsAndFloats(WebCore::LineLayoutState&, bool)
12  0x114d21ad0 WebCore::RenderBlockFlow::layoutLineBoxes(bool, WebCore::LayoutUnit&, WebCore::LayoutUnit&)
13  0x114cfa382 WebCore::RenderBlockFlow::layoutInlineChildren(bool, WebCore::LayoutUnit&, WebCore::LayoutUnit&)
14  0x114cf93c8 WebCore::RenderBlockFlow::layoutBlock(bool, WebCore::LayoutUnit)
15  0x114cc57c9 WebCore::RenderBlock::layout()
16  0x114cfcbf3 WebCore::RenderBlockFlow::layoutBlockChild(WebCore::RenderBox&, WebCore::RenderBlockFlow::MarginInfo&, WebCore::LayoutUnit&, WebCore::LayoutUnit&)
17  0x114cfa5e6 WebCore::RenderBlockFlow::layoutBlockChildren(bool, WebCore::LayoutUnit&)
18  0x114cf93eb WebCore::RenderBlockFlow::layoutBlock(bool, WebCore::LayoutUnit)
19  0x114cc57c9 WebCore::RenderBlock::layout()
20  0x114cfcbf3 WebCore::RenderBlockFlow::layoutBlockChild(WebCore::RenderBox&, WebCore::RenderBlockFlow::MarginInfo&, WebCore::LayoutUnit&, WebCore::LayoutUnit&)
21  0x114cfa5e6 WebCore::RenderBlockFlow::layoutBlockChildren(bool, WebCore::LayoutUnit&)
22  0x114cf93eb WebCore::RenderBlockFlow::layoutBlock(bool, WebCore::LayoutUnit)
23  0x114cc57c9 WebCore::RenderBlock::layout()
24  0x114fefddd WebCore::RenderView::layoutContent(WebCore::LayoutState const&)
25  0x114ff0c3a WebCore::RenderView::layout()
26  0x113eb6bf9 WebCore::FrameView::layout(bool)
27  0x113b16990 WebCore::Document::implicitClose()
28  0x113e806ab WebCore::FrameLoader::checkCallImplicitClose()
29  0x113e8037e WebCore::FrameLoader::checkCompleted()
30  0x113e7ee82 WebCore::FrameLoader::finishedParsing()
31  0x113b23dd3 WebCore::Document::finishedParsing()
Comment 1 Ahmad Saleem 2022-11-01 17:00:57 PDT 
This comment seems to mention that it was Blink specific:

https://bugs.chromium.org/p/chromium/issues/detail?id=450598#c3

This commit was pushed to fix issue in Blink:

https://src.chromium.org/viewvc/blink?view=revision&revision=194638

and Webkit has similar code here:

https://github.com/WebKit/WebKit/blob/0d7afc5a45c140c44497a81e92416f01306be877/Source/WebCore/rendering/shapes/ShapeOutsideInfo.cpp#L172

and I am not super sure, whether we need to do anything or not but appreciate if someone else can comment, it would be great. Thanks!