Bug 293179 – v8.dev: wrong height for span in grid listing

• Component: Layout and Rendering
• Status: RESOLVED FIXED

[Ahmad Saleem]

Hi Team,

Going through random website, I came across another Web Compat issue, so raising it now.

Website Link: https://v8.dev/features/explicit-resource-management#explicit-resource-management-support

*** Steps to Reproduce ***
1) Open above article
2) Try to hover over image icons of Chrome, Mozilla etc and notice that `hover` does not cover full container height

*** Expected Result ***
Hover color cover full container width and height and width should be more square rather than elongated one.

*** Actual Result ***

Height is 172px while width is 146px in Safari while in Chrome, it is 146 x 146 (removing subpixel deliberately here).

*** Other browsers ***

Chrome Canary 138.0.7184.0 (Official Build) canary (arm64) - Works
Safari 18.5 - Does not work
WebKit ToT (295054@main) - Does not work
Firefox Nightly 140 (20250516092940) - Works
Ladybird (b559965448e37e68f52d119ba0aea0b3f94a0f7f) - hover color is different but height and width works.

Just raising, so we can fix it.

Thanks!

[Ahmad Saleem]

Created attachment 475282 [details]
Safari (Broken) Reference Screenshot

[Radar WebKit Bug Importer]

<rdar://problem/151655455>

[Karl Dubost]

Icons are in a grid applied to a ul/li setup. 

<ul class="feature-support">
    <li class="environment has-link has-support">
        <a href="https://chromestatus.com/feature/5071680358842368">
            <span class="icon chrome">Chrome:</span> 
            <span class="support">supported since version 
                <span class="version">134</span>
            </span>
        </a>
    </li>
…
</ul>

.feature-support {
    grid-gap: .5em;
    background: var(--main-background-color);
    display: grid;
    grid-template-columns: 1fr 1fr 1fr 1fr 1fr;
    margin-bottom: .5em;
    padding-left: 0;
}

the hover is applied to the anchor, not the li element.

footer a:focus, footer a:hover, main a:focus, main a:hover {
    background-color: #0a50c2;
    background-color: var(--main-and-footer-link-color);
    color: #fff;
    color: var(--main-background);
}

The li doesn't adjust its height to the full height of the anchor.

[Karl Dubost]

OK reduced test case:
https://codepen.io/webcompat/pen/wBBbNxE

ul {
  width: 500px;
    background-color: gold;
    display: grid;
    grid-template-columns: 1fr 1fr 1fr 1fr 1fr;
}
li {
  background-color:pink;
  border: 2px solid red;}

span {
  display:block;
  padding: 100% 0 0}

<ul>
  <li><span> </span></li>
  <li><span> </span></li>
  <li><span> </span></li>
  <li><span> </span></li>
  <li><span> </span></li>
</ul>

[Karl Dubost]

There is probably an already existing bug about that.

[Sammy Gill]

Created attachment 475391 [details]
Testcase

Attaching further reduced test case

[Sammy Gill]

From a bit of debugging it doesn't quite seem to be a grid issue. You can achieve the same bug by removing display: grid from the ul.

A render tree dump seems to give the following


B---YLC--L --* RenderView at (0,0) size 2560x1356 renderer (0x134238150) layout box (0x0)
B----L---L --    HTML RenderBlock at (0,0) size 2560x150 renderer (0x1341ec230) layout box (0x0) node (0x1340ac6a0)
B--------- --      BODY RenderBody at (8,16) size 2544x118 renderer (0x1341ec3a0) layout box (0x0) node (0x1340ac730) (layout overflow 0,0 2544x118) (visual overflow 0,-1 2544x120)
B--------L --        UL RenderGrid at (0,0) size 140x118 renderer (0x15a380000) layout box (0x0) node (0x1342e4340) (layout overflow 0,0 140x118) (visual overflow 0,-1 141x120)
B--------L --          LI RenderListItem at (40,0) size 100x118 renderer (0x1343e4100) layout box (0x0) node (0x1340ac7c0) (layout overflow -17,0 117x118) (visual overflow -17,-1 118x120)
B---Y----- --            RenderBlock at (0,0) size 100x18 renderer (0x1341ec680) layout box (0x13423c340) (layout overflow -17,0 117x18) (visual overflow -17,0 117x18)
           --              line at (0.00,0.00) size (100.00x18.00) baseline (14.00) enclosing top (0.00) bottom (18.00)
           --                Root inline box at (0.00,0.00) size (0.00x18.00)
           --                Run(s):
           --                  Atomic box at (-17.00,0.00) size 7.00x18.00 renderer->(0x1341e8380)
I---Y----- --              RenderListMarker (::marker) at (-17,0) size 7x18 renderer (0x1341e8380) layout box (0x13423c410)
B--------- --            SPAN RenderBlock at (0,18) size 100x100 renderer (0x1341ec510) layout box (0x0) node (0x1340ac850) (layout overflow 0,0 100x100) (visual overflow -1,-1 102x102)

The extra spacing at the top looks like it is coming from the fact that the list item is computing its height from its contents and the list marker content adds to it. Adding list-style: none; to the ul causes us to size the list item the same as other engines

[Karl Dubost]

Created attachment 475394 [details]
rendering in safari, firefox, chrome

[Karl Dubost]

interesting looking at 
https://searchfox.org/wubkat/source/Source/WebCore/rendering/RenderListMarker.cpp

I have seen 
https://searchfox.org/wubkat/rev/a7ddc6651da8ec6a5337847fae050ddf658db1b7/Source/WebCore/rendering/RenderListMarker.cpp#424-429
```cpp
LayoutUnit RenderListMarker::lineHeight(bool firstLine, LineDirectionMode direction, LinePositionMode linePositionMode) const
{
    if (!isImage())
        return m_listItem->lineHeight(firstLine, direction, PositionOfInteriorLineBoxes);
    return RenderBox::lineHeight(firstLine, direction, linePositionMode);
}
```


So I tried `line-height: 0`. 
This is also fixing the issue for Safari.

[Karl Dubost]

Maybe related 
https://github.com/chromium/chromium/commit/b71361654f918e79822e8db957ffc2ee361e3ff2
https://github.com/w3c/csswg-drafts/issues/2418

[alan]

Created attachment 475476 [details]
[fast-cq]Patch

[EWS]

Committed 295819@main (7352a31480b4): <https://commits.webkit.org/295819@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 475476 [details].