1793071 - [wpt-sync] Sync PR 36104 - Avoid invalid class C break when a first inflow child fits beside float.

Status: RESOLVED FIXED

(Core :: Layout, task, P4)

Description

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Sync web-platform-tests PR 36104 into mozilla-central (this bug is closed when the sync is complete).

PR: https://github.com/web-platform-tests/wpt/pull/36104
Details from upstream follow.

Morten Stenshorne <[e-mail]> wrote:

Avoid invalid class C break when a first inflow child fits beside float.

If a container was cleared by a preceding float, and said container has
a float and a BFC root child, and the BFC root fits beside the float,
we'd incorrectly detect container separation before the BFC root, even
though there was no gap between it and its container.

We don't really need to let child_margin_got_separated be part of the
container separation check, since we're already comparing block-offsets.
That said, the whole child_margin_got_separated thing is a bit sketchy,
in that there may be false positives. Added a TODO.

Note that, among the tests included, only the -004 one would fail
without this fix. The two others are just regression tests, to make sure
that we still detect valid class C breakpoints in very similar
situations.

Bug: 1368518
Change-Id: I78ff2f5081e4a6878d4556ddbd859286da12e7d3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3921636
Commit-Queue: Morten Stenshorne \<[e-mail]>
Reviewed-by: Ian Kilpatrick \<[e-mail]>
Cr-Commit-Position: refs/heads/main@{#1053246}

Comment 1

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Pushed to try (stability) https://treeherder.mozilla.org/#/jobs?repo=try&revision=741e483c6de31b692d306f947b966c2100409b9f

Comment 2

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

CI Results

Ran 9 Firefox configurations based on mozilla-central, and Firefox, Chrome, and Safari on GitHub CI

Total 3 tests

Status Summary

Firefox

PASS: 2
FAIL: 1

Chrome

PASS: 2
FAIL: 1

Safari

PASS: 3

Links

Gecko CI (Treeherder)
GitHub PR Head
GitHub PR Base

Details

New Tests That Don't Pass

• /css/css-break/class-c-breakpoint-after-float-004.html [wpt.fyi]: FAIL (Chrome: FAIL, Safari: PASS)

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0ab7208335a3
[wpt PR 36104] - Avoid invalid class C break when a first inflow child fits beside float., a=testonly
https://hg.mozilla.org/integration/autoland/rev/04da07c59a70
[wpt PR 36104] - Update wpt metadata, a=testonly

Comment 4

[Iulian Moraru]

https://hg.mozilla.org/mozilla-central/rev/0ab7208335a3
https://hg.mozilla.org/mozilla-central/rev/04da07c59a70