Closed Bug 1744737 Opened 2 years ago Closed 2 years ago

[wpt-sync] Sync PR 31929 - Correct document order for fixedpos flex item inside abspos legacy flex.

Categories

(Core :: Layout, task, P4)

Product:
Core
Component:
Layout
Type:
task

Tracking

()

Status:
RESOLVED FIXED
Milestone:
97 Branch
Tracking Flags:
Tracking Status
firefox97 --- fixed

People

(Reporter: mozilla.org, Unassigned)

References

(
URL
)

Details

(Whiteboard: [wptsync downstream])

Sync web-platform-tests PR 31929 into mozilla-central (this bug is closed when the sync is complete).

PR: https://github.com/web-platform-tests/wpt/pull/31929
Details from upstream follow.

Morten Stenshorne <mstensho@chromium.org> wrote:

Correct document order for fixedpos flex item inside abspos legacy flex.

If there's an OOF flex item inside an OOF legacy flex container, and the
flex container isn't the containing block for the item (e.g. fixed-
positioned inside absolute-positioned), check one extra time when
handling them at the containing block.

LayoutBlock::PositionedObjects() gets OOFs out of document order upon
re-layout on a general basis, if there's a fixed-positioned object
inside another OOF, so that we may end up laying out the child before
the parent. If, when eventually laying out the parent, we mark the child
for layout, we'd never get back to laying it out, and DCHECKs would
fail.

The only known actual problem with having objects out of document order
is precisely what's described above, so the fix is limited to that.

Hopefully the legacy engine is removed before we discover any problems
with my fix. :-p

Bug: 1269228
Change-Id: Ifc212e2b8baa6b9fcf58a5714fa7a8a1139f4b87
Reviewed-on: https://chromium-review.googlesource.com/3320257
WPT-Export-Revision: 83de92b338fee19b36eaa679551a71ad7390e97c

Component: web-platform-tests → Layout
Product: Testing → Core

CI Results

Ran 11 Firefox configurations based on mozilla-central, and Firefox, Chrome, and Safari on GitHub CI

Total 1 tests

Status Summary

Firefox

PASS: 1

Chrome

PASS: 1

Safari

PASS: 1

Links

Gecko CI (Treeherder)
GitHub PR Head
GitHub PR Base

Pushed by wptsync@mozilla.com:
https://hg.mozilla.org/integration/autoland/rev/6196e4a0499a
[wpt PR 31929] - Correct document order for fixedpos flex item inside abspos legacy flex., a=testonly

https://hg.mozilla.org/mozilla-central/rev/6196e4a0499a

Status: NEW → RESOLVED
Closed: 2 years ago
status-firefox97: --- → fixed
Resolution: --- → FIXED
Target Milestone: --- → 97 Branch
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