Bug 197731

Summary:	Sometimes we hit ASSERT(!parentClipRect.isInfinite()) in RenderLayerBacking::computeParentGraphicsLayerRect
Product:	WebKit	Reporter:	Simon Fraser (smfr) <simon.fraser>
Component:	Compositing	Assignee:	Nobody <webkit-unassigned>
Status:	RESOLVED DUPLICATE
Severity:	Normal	CC:	simon.fraser, zalan
Priority:	P2
Version:	WebKit Nightly Build
Hardware:	Unspecified
OS:	Unspecified
See Also:	https://bugs.webkit.org/show_bug.cgi?id=126160

Description Simon Fraser (smfr) 2019-05-08 21:11:49 PDT

At webkit r245059, we sometimes assert at ASSERT(!parentClipRect.isInfinite()) in RenderLayerBacking::computeParentGraphicsLayerRect.

I can reproduce this in DumpRenderTree with accessibility/media-element.html

Comment 1 Simon Fraser (smfr) 2019-05-08 21:13:46 PDT

This code runs when we have a m_ancestorClippingLayer, and we make one based on the result of RenderLayerCompositor::clippedByAncestor(), which uses:

layer.backgroundClipRect(RenderLayer::ClipRectsContext(computeClipRoot, TemporaryClipRects)).isInfinite()

However, RenderLayerBacking::computeParentGraphicsLayerRect() is doing:

        ShouldRespectOverflowClip shouldRespectOverflowClip = compositedAncestor->isolatesCompositedBlending() ? RespectOverflowClip : IgnoreOverflowClip;
        RenderLayer::ClipRectsContext clipRectsContext(compositedAncestor, TemporaryClipRects, IgnoreOverlayScrollbarSize, shouldRespectOverflowClip);
        LayoutRect parentClipRect = m_owningLayer.backgroundClipRect(clipRectsContext).rect(); // FIXME: Incorrect for CSS regions.

so 'shouldRespectOverflowClip' differs.

Comment 2 Simon Fraser (smfr) 2019-05-08 21:21:06 PDT

That code came from https://trac.webkit.org/changeset/168314/webkit

Comment 3 Simon Fraser (smfr) 2019-05-08 21:24:14 PDT


*** This bug has been marked as a duplicate of bug 197695 ***