[webkit-reviews] review denied: [Bug 103329] [CSS Grid Layout] Properly support for z-index on grid items : [Attachment 233000] Patch

[bugzilla-daemon at webkit.org]

Benjamin Poulain <benjamin at webkit.org> has denied Manuel Rego Casasnovas
<rego at igalia.com>'s request for review:
Bug 103329: [CSS Grid Layout] Properly support for z-index on grid items
https://bugs.webkit.org/show_bug.cgi?id=103329

Attachment 233000: Patch
https://bugs.webkit.org/attachment.cgi?id=233000&action=review

------- Additional Comments from Benjamin Poulain <benjamin at webkit.org>
View in context: https://bugs.webkit.org/attachment.cgi?id=233000&action=review


> Source/WebCore/rendering/style/RenderStyle.cpp:676
> +    // StyleResolver has ensured that zIndex is non-auto only if it's
applicable.

I would consider a series of assertions here to ensure that comment is true.
Otherwise a mistake in the future could cause us to overpaint like crazy.

> Source/WebCore/rendering/style/RenderStyle.cpp:678
> +    if (m_box->zIndex() != other->m_box->zIndex()
> +	   || m_box->hasAutoZIndex() != other->m_box->hasAutoZIndex())

This can be on one line, no need to use Google's short line style.

> LayoutTests/ChangeLog:13
> +	   *
fast/css-grid-layout/grid-item-z-index-change-repaint-expected.html: Added.
> +	   * fast/css-grid-layout/grid-item-z-index-change-repaint.html: Added.


I would add more tests similar to this:

Here you test if changing the z-index cause a correct repaint.

There is one area of the patch that is not tested by this: going in and out of
grid position. I would add tests ensuring
1) An element supports the z-index once it gets a grid positioning.
2) It repaints accordingly.