Bug 122027 – ASSERTION FAILED: foundContainer in RenderGeometryMap::mapToContainer(WebCore::TransformState &, const WebCore::RenderLayerModelObject *) const

• Status: ASSIGNED
• Component: Layout and Rendering

[zalan]

SSIA

[zalan]

Created attachment 212830 [details]
test reduction

[zalan]

<rdar://problem/15082483>

[zalan]

This happens when the layout container tree != painting container tree.
With CSS filters (blur in this case), when a child element is (absolute)positioned, its parent in layout terms might differ from its parent in painting terms. The geometry map is initiated with layout containers, but in RenderLayer::updateLayerPositionsAfterScroll(), we pass the repaint container to the mapping function, which in turn fails to transform the coordinates as repaint container != layout container ->assert. -see computeRepaintRects(renderer().containerForRepaint(), geometryMap);

[Vicki Pfau]

This is likely the same bug as https://bugs.webkit.org/show_bug.cgi?id=117981

[zalan]

*** Bug 117981 has been marked as a duplicate of this bug. ***

[zalan]

(In reply to comment #3)
> This happens when the layout container tree != painting container tree.
> With CSS filters (blur in this case), when a child element is (absolute)positioned, its parent in layout terms might differ from its parent in painting terms. The geometry map is initiated with layout containers, but in RenderLayer::updateLayerPositionsAfterScroll(), we pass the repaint container to the mapping function, which in turn fails to transform the coordinates as repaint container != layout container ->assert. -see computeRepaintRects(renderer().containerForRepaint(), geometryMap);

Let me rephrase it. The container tree for the absolute positioned object is not  the same as the painting tree unless the parent has transform or it is positioned too. In this case, the parent has CSS filter only and while it requires a dedicated render layer, when it comes to figuring out the containing block, it is skipped.

[Carlos Bentzen]

I just hit this assertion in WPE running Youtube TV.