1797250 - [wpt-sync] Sync PR 36642 - Write column-count back to legacy correctly.

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 36642 into mozilla-central (this bug is closed when the sync is complete).

PR: https://github.com/web-platform-tests/wpt/pull/36642
Details from upstream follow.

Morten Stenshorne <[e-mail]> wrote:

Write column-count back to legacy correctly.

Column-count was written back to legacy by resolving it separately after
actual layout. At this point we don't have the information we need - the
content box inline-size. We were actually passing the available
inline-size from the containing block instead, which is wrong (unless
the content-box inline-size of the multicol container happens to be
identical to the containing block inline-size), and worse: it could be
indefinite, which may be the case if the multicol container is a grid
item. We'd end up with both division by zero and correctness issues.

It's much better to write column-count back during actual multicol
layout, just like we already do for column inline-size.

Bug: 1349884
Change-Id: I6ab3f13bc3bc3f47bda12bf9c54f1bb1171ffda4
Reviewed-on: https://chromium-review.googlesource.com/3970622
WPT-Export-Revision: 8b60ac4f6e5222168e486bb2a3558c817d93a32d

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=8e08e2dc90690a5961c867a68cab77e0a508eed5

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0e7b6b5495aa
[wpt PR 36642] - Write column-count back to legacy correctly., a=testonly
https://hg.mozilla.org/integration/autoland/rev/2e2642db0151
[wpt PR 36642] - Update wpt metadata, a=testonly

Comment 3

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

Test result changes from PR not available.

Comment 4

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/0e7b6b5495aa
https://hg.mozilla.org/mozilla-central/rev/2e2642db0151