Bug 231244 – Regression (r283339): [ iOS15 Debug ] fast/attachment tests are ASSERTION FAILED: !textPosition.x

• Component: New Bugs
• Status: RESOLVED CONFIGURATION CHANGED

fast/attachment/attachment-label-highlight.html
fast/attachment/attachment-title-with-rtl.html

Are crashing on iOS 15 Debug.

History: https://results.webkit.org/?suite=layout-tests&suite=layout-tests&test=fast%2Fattachment%2Fattachment-label-highlight.html&test=fast%2Fattachment%2Fattachment-title-with-rtl.html

Stderr: 

ASSERTION FAILED: !textPosition.x
./platform/graphics/coretext/DrawGlyphsRecorderCoreText.cpp(305) : void WebCore::DrawGlyphsRecorder::recordDrawGlyphs(CGRenderingStateRef, CGGStateRef, const CGAffineTransform *, const CGGlyph *, const CGPoint *, size_t)
1   0x138fc4e99 WTFCrash
2   0x15cd408bb WTFCrashWithInfo(int, char const*, char const*, int)
3   0x161366010 WebCore::DrawGlyphsRecorder::recordDrawGlyphs(CGRenderingState*, CGGState*, CGAffineTransform const*, unsigned short const*, CGPoint const*, unsigned long)
4   0x16136438c WebCore::drawGlyphs(CGContextDelegate*, CGRenderingState*, CGGState*, CGAffineTransform const*, unsigned short const*, CGPoint const*, unsigned long)
5   0x1141b8e21 draw_glyphs.11583
6   0x1141b8a9b CGContextShowGlyphsWithAdvances
7   0x110e53650 EnumerateOverlappingGlyphs(CGContext*, TFont const&, unsigned short const*, long, int, void (CFRange, bool) block_pointer)
8   0x110e551f3 CTFontDrawGlyphsWithAdvancesInternal
9   0x110e1bf17 TRun::DrawGlyphs(CGContext*, CFRange) const
10  0x110e34ed0 TLine::DrawGlyphs(CGContext*) const
11  0x161368304 WebCore::DrawGlyphsRecorder::drawNativeText(__CTFont const*, double, __CTLine const*, CGRect)
12  0x15f22cea5 WebCore::paintAttachmentText(WebCore::GraphicsContext&, WebCore::RenderAttachmentInfo&)
13  0x15f22c54c WebCore::RenderThemeIOS::paintAttachment(WebCore::RenderObject const&, WebCore::PaintInfo const&, WebCore::IntRect const&)
14  0x161a2a613 WebCore::RenderTheme::paint(WebCore::RenderBox const&, WebCore::ControlStates&, WebCore::PaintInfo const&, WebCore::LayoutRect const&)
15  0x1617abd72 WebCore::RenderBox::paintBoxDecorations(WebCore::PaintInfo&, WebCore::LayoutPoint const&)
16  0x16199faae WebCore::RenderReplaced::paint(WebCore::PaintInfo&, WebCore::LayoutPoint const&)
17  0x1618392b9 WebCore::paintPhase(WebCore::RenderElement&, WebCore::PaintPhase, WebCore::PaintInfo&, WebCore::LayoutPoint const&)
18  0x161839248 WebCore::RenderElement::paintAsInlineBlock(WebCore::PaintInfo&, WebCore::LayoutPoint const&)
19  0x160a3d350 WebCore::LayoutIntegration::LineLayout::paint(WebCore::PaintInfo&, WebCore::LayoutPoint const&)
20  0x1617a25d4 WebCore::RenderBlockFlow::paintInlineChildren(WebCore::PaintInfo&, WebCore::LayoutPoint const&)
21  0x161778a52 WebCore::RenderBlock::paintContents(WebCore::PaintInfo&, WebCore::LayoutPoint const&)
22  0x16177a12e WebCore::RenderBlock::paintObject(WebCore::PaintInfo&, WebCore::LayoutPoint const&)
23  0x16177836b WebCore::RenderBlock::paint(WebCore::PaintInfo&, WebCore::LayoutPoint const&)
24  0x161778fc2 WebCore::RenderBlock::paintChild(WebCore::RenderBox&, WebCore::PaintInfo&, WebCore::LayoutPoint const&, WebCore::PaintInfo&, bool, WebCore::RenderBlock::PaintBlockType)
25  0x161778bf7 WebCore::RenderBlock::paintChildren(WebCore::PaintInfo&, WebCore::LayoutPoint const&, WebCore::PaintInfo&, bool)
26  0x161778b66 WebCore::RenderBlock::paintContents(WebCore::PaintInfo&, WebCore::LayoutPoint const&)
27  0x16177a12e WebCore::RenderBlock::paintObject(WebCore::PaintInfo&, WebCore::LayoutPoint const&)
28  0x16177836b WebCore::RenderBlock::paint(WebCore::PaintInfo&, WebCore::LayoutPoint const&)
29  0x1618ce300 WebCore::RenderLayer::paintForegroundForFragmentsWithPhase(WebCore::PaintPhase, WTF::Vector<WebCore::LayerFragment, 1ul, WTF::CrashOnOverflow, 16ul, WTF::FastMalloc> const&, WebCore::GraphicsContext&, WebCore::RenderLayer::LayerPaintingInfo const&, WTF::OptionSet<WebCore::PaintBehavior>, WebCore::RenderObject*)
30  0x1618cc061 WebCore::RenderLayer::paintForegroundForFragments(WTF::Vector<WebCore::LayerFragment, 1ul, WTF::CrashOnOverflow, 16ul, WTF::FastMalloc> const&, WebCore::GraphicsContext&, WebCore::GraphicsContext&, WebCore::LayoutRect const&, bool, WebCore::RenderLayer::LayerPaintingInfo const&, WTF::OptionSet<WebCore::PaintBehavior>, WebCore::RenderObject*)
31  0x1618c7e0f WebCore::RenderLayer::paintLayerContents(WebCore::GraphicsContext&, WebCore::RenderLayer::LayerPaintingInfo const&, WTF::OptionSet<WebCore::RenderLayer::PaintLayerFlag>)
com.apple.WebKit.WebContent.Development terminated (pid 85202) because the process crashed

Created attachment 440239 [details]
Crash log

[Radar WebKit Bug Importer]

<rdar://problem/83896187>

According to the history, it appears that the crash started somewhere between r283320  and r283355

I was able to reproduce the crash locally using fast/attachment/attachment-label-highlight.html --debug --ios-simulator.

The test crashed with r283339 and passed with r283332 (No revisions to test in-between).

I think https://trac.webkit.org/changeset/283339/webkit may have caused the crash.

Reverted the change here https://trac.webkit.org/changeset/283577/webkit

[Devin Rousso]

After talking with @Myles Maxfield, we believe that the failing `ASSERT` is no longer (and may never have been) accurate/needed. CT is allowed to modify the text position between the `CGContextSetTextPosition` call and `DrawGlyphsRecorder::recordDrawGlyphs`. I tested this by calling `CGContextSetTextPosition` with manually overridden coordinates and visually confirming that the output was moved by the relevant amount.