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.
Created attachment 355541 [details]
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.
Oops, I initially thought this is a very recent regression but it's not that. The bug simply doesn't reproduce in Safari.
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.
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.
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.
*** Bug 192068 has been marked as a duplicate of this bug. ***
It paints when we paint with accelerated drawing, but not when we don't.