Bug 249987 – Inapplicable top, bottom style shouldn't affect height calculation

• Status: NEW
• Component: Layout and Rendering

[Ahmad Saleem]

Hi Team,

While going through WebKit, I came across another failing test case in Safari 16.2 & Safari Technology Preview 160 while passing in Chrome Canary 111 and Firefox Nightly 110:

Test Case - https://jsfiddle.net/vrsmce24/

Blink Commit - https://chromium.googlesource.com/chromium/blink/+/034a32ac2e53bac07e201ba7cc1d6af6ebfd3dc5

I don't know whether it is possible to merge 1-1 but just wanted to raise so we can track it.

Thanks!

[Ahmad Saleem]

Seems we need to update this: https://searchfox.org/wubkat/source/Source/WebCore/rendering/RenderBoxModelObject.cpp#286

[Radar WebKit Bug Importer]

<rdar://problem/103893875>

[Ahmad Saleem]

NOTE - This issue seems to be something similar to cache related issues, because if I refresh same tab again, it passes. Very strange!

[Ahmad Saleem]

We have this:

https://searchfox.org/wubkat/source/Source/WebCore/rendering/RenderBoxModelObject.cpp#268

 if (isOutOfFlowPositionedWithImplicitHeight(*cb))
        return nullptr;
    

and 'isOutOfFlowPositionedWithImplicitHeight' function is exactly as this patch:

static inline bool isOutOfFlowPositionedWithImplicitHeight(const RenderBoxModelObject& child)
{
    return child.isOutOfFlowPositioned() && !child.style().logicalTop().isAuto() && !child.style().logicalBottom().isAuto();
}