1728570 - [wpt-sync] Sync PR 30286 - Replace forced-break-in-nested-columns.html with a correct WPT test.

Status: RESOLVED FIXED

(Core :: Layout: Columns, task, P4)

Description

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

Sync web-platform-tests PR 30286 into mozilla-central (this bug is closed when the sync is complete).

PR: https://github.com/web-platform-tests/wpt/pull/30286
Details from upstream follow.

b'Morten Stenshorne <[e-mail]>' wrote:

Replace forced-break-in-nested-columns.html with a correct WPT test.

The old test was assuming a legacy engine implementation limitation,
where we're unable to push the first fragment of a multicol container to
the next outer fragmentainer if there was no room for its contents in
the current outer fragmentainer.

In the test, see the first DIV child of the inner .mc. The legacy engine
would just push the line inside that DIV to the next outer
fragmentainer, even if there's no valid breakpoint there. The correct
behavior is to push the first fragment of the inner multicol container
itself to the next outer fragmentainer (there's a perfect breakpoint
after the first DIV child of the outer .mc. LayoutNG block fragmentation
gets this right.

Bug: 829028
Change-Id: I55950c5aad3418b49dabe12debd43317cf578c96
Reviewed-on: https://chromium-review.googlesource.com/3135656
WPT-Export-Revision: 278b71eb00c77301ae07ba4081a067c05fd6da48

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=87a4ca01218c68b0918aee2f12b8ad22b3770256

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/6e8f7aa62a29
[wpt PR 30286] - Replace forced-break-in-nested-columns.html with a correct WPT test., a=testonly

Comment 3

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

Test result changes from PR not available.

Comment 4

[Marian-Vasile Laza]

https://hg.mozilla.org/mozilla-central/rev/6e8f7aa62a29