[CSSRegions] Crash while repainting an invalid region

[Mihnea Ovidenie]

A invalid region, part of a dependency cycle, should not attempt to repaint the content from the associated named flow.

[Mihnea Ovidenie]

Created attachment 219900 [details]
Patch

[Daniel Bates]

Comment on attachment 219900 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=219900&action=review

This looks sane to me. Feel free to have a domain expert look over this patch.

> LayoutTests/fast/regions/repaint/invalid-region-repaint-crash.html:4
> +        <script src="../../repaint/resources/text-based-repaint.js" type="text/javascript"></script>

Please remove the HTML attribute type as it's unnecessary given that this document is an HTML5 document.

> Source/WebCore/rendering/RenderLayer.cpp:6278
> +        RenderNamedFlowFragment* region = toRenderBlockFlow(&renderer())->renderNamedFlowFragment();

Notice that we generate a toRenderBlockFlow()-variant that takes and returns a reference. For you consideration, I suggest we use this variant to remove the address-of operator and to document the "non-nullness" of the return value of toRenderBlockFlow() since renderer() is guaranteed to be non-null.

RenderNamedFlowFragment* region = toRenderBlockFlow(renderer()).renderNamedFlowFragment();

[Mihnea Ovidenie]

Created attachment 219958 [details]
Patch for landing

[WebKit Commit Bot]

Comment on attachment 219958 [details]
Patch for landing

Clearing flags on attachment: 219958

Committed r161054: <http://trac.webkit.org/changeset/161054>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.