Bug 286002 – REGRESSION (286055@main): Relative-positioned input elements in scroll areas don't render outlines

• Component: Compositing
• Status: RESOLVED FIXED

[Georges Basile Stavracas Neto]

Created attachment 473907 [details]
Reproducer

This seems to be a regression introduced by https://commits.webkit.org/286055@main for fixing https://bugs.webkit.org/show_bug.cgi?id=282478

See the attachment for a reproducer.

Specifically, commit https://commits.webkit.org/286055@main introduces the following line:

```
if (localPaintFlags.contains(PaintLayerFlag::PaintingOverflowContents))
            return false;
```

and this is preventing the outline from the input field from rendering.

[Radar WebKit Bug Importer]

<rdar://problem/142995142>

[Georges Basile Stavracas Neto]

Pull request: https://github.com/WebKit/WebKit/pull/39130

[Simon Fraser (smfr)]

Seems to happen when the <input> itself is `position:relative` (but a relative container is OK).

[Simon Fraser (smfr)]

The issue here is that we want to avoid painting the outline *for the scroller itself* in the scrolled contents layer (hence the `return false` for PaintingOverflowContents), but we do need to paint the outline in any descendant layers.

[Simon Fraser (smfr)]

I have an alternative fix.

[Simon Fraser (smfr)]

Pull request: https://github.com/WebKit/WebKit/pull/39229

[EWS]

Committed 289154@main (d183e4fe4bcd): <https://commits.webkit.org/289154@main>

Reviewed commits have been landed. Closing PR #39229 and removing active labels.