Bug 191930 – Radial gradient with href sometimes doesn't paint in WK1 or with the very first layout in WK2

• Component: SVG
• Status: NEW

[Ryosuke Niwa]

When href content attribute is used on radial gradient to copy attributes from another radial gradient,
the very first paint / layout in MiniBrowser and DumpRenderTree doesn't reference to it.

The problem doesn't seem to reproduce in Safari perhaps because it triggers multiple layouts.

[Ryosuke Niwa]

Created attachment 355541 [details]
Reduction

To reproduce the bug, open the attached bug in MiniBrowser. The issue reproduces the very first time the document is loaded.

It appears that reproducing the problem requires a new WK2 window. In WK1, the green box never appears regardless of how many window sizes I trigger so that's a pretty serious bug.

[Ryosuke Niwa]

Oops, I initially thought this is a very recent regression but it's not that. The bug simply doesn't reproduce in Safari.

[Ryosuke Niwa]

There are suspicious early exists for when renderer() is null in SVGRadialGradientElement::collectGradientAttributes but removing them didn't fix the issue. There is some kind of dependency resolution that's broken here since the bug doesn't reproduce if href isn't specified on radial gradient.

[Ryosuke Niwa]

Hm... tests like LayoutTests/svg/custom/radialGradient-focal-radius.svg is working so it's only the subset of features that don't quite work.

[Ryosuke Niwa]

It looks like updating href content attribute doesn't update the rendering at all: https://bugs.webkit.org/show_bug.cgi?id=191934

I suspect these two bugs are related.

[Simon Fraser (smfr)]

*** Bug 192068 has been marked as a duplicate of this bug. ***

[Simon Fraser (smfr)]

It paints when we paint with accelerated drawing, but not when we don't.

[Simon Fraser (smfr)]

<rdar://problem/46298791>

[Radar WebKit Bug Importer]

<rdar://problem/46675465>