1758723 - [css-multicol] column-span:all should not become a spanner, when inside transform (or other elements which establish fixedpos containing block), per csswg resolution

Status: RESOLVED FIXED

(Core :: Layout: Columns, defect)

Description

[Mozilla Apprentice]

A resolution was made for csswg-drafts/#6805.

[css-multicol] Should column-span:all inside a transform really become a spanner?

• RESOLVED: Accept proposal that elements which establish fixedpos containing block also block descendant spanners

Discussion.

Comment 1

[Daniel Holbert [:dholbert]]

It looks like we should just add a new case to https://searchfox.org/mozilla-central/rev/131f3af9a49d2203adb7b7ef30dcc37c9f1aa10b/layout/base/nsCSSFrameConstructor.cpp#355-359

Comment 2

[Daniel Holbert [:dholbert]]

Attachment: testcase 1

Comment 3

[Daniel Holbert [:dholbert]]

Attachment: non-refrerence-case for testcase 1 (should not match)

Comment 4

[Daniel Holbert [:dholbert]]

Attachment: reference case for testcase 1

Comment 5

[Daniel Holbert [:dholbert]]

STR:
Compare attached testcase, non-reference case, and reference case.

ACTUAL RESULTS:
Testcase 1 matches the non-reference case.
Testcase 1 does not match the reference case.

EXPECTED RESULTS:
Testcase 1 should not match the non-reference case.
Testcase 1 should not the reference case.

Firefox Nightly v100 gives ACTUAL RESULTS.
Chrome dev-channel v100 gives EXPECTED RESULTS (i.e. it looks like they've already implemented this spec change, apparently in https://bugs.chromium.org/p/chromium/issues/detail?id=1267847 )

Comment 6

[Daniel Holbert [:dholbert]]

Note that there's an existing web-platform-test for this ( https://searchfox.org/mozilla-central/rev/eeeba8183d3268e0d563c2becf9f4adc21a37368/testing/web-platform/tests/css/css-multicol/multicol-span-all-017.tentative.html ) but it doesn't have a reference case specified, so it's inactive right now. I called the author/reviewer's attention to this in https://github.com/web-platform-tests/wpt/pull/31837#issuecomment-1063355494 and presumably that will be fixed soon.

Comment 7

[Daniel Holbert [:dholbert]]

(In reply to Daniel Holbert [:dholbert] from comment #6)

Note that there's an existing web-platform-test for this ( https://searchfox.org/mozilla-central/rev/eeeba8183d3268e0d563c2becf9f4adc21a37368/testing/web-platform/tests/css/css-multicol/multicol-span-all-017.tentative.html ) but it doesn't have a reference case specified, so it's inactive

update: this test was fixed (and .tentative dropped from its name).
It now lives here:
https://searchfox.org/mozilla-central/source/testing/web-platform/tests/css/css-multicol/multicol-span-all-017.html
https://wpt.fyi/results/css/css-multicol/multicol-span-all-017.html

Comment 8

[David Shin[:dshin]]

Attachment: Bug 1758723 - Suppress `column-span:all` for descendants of a containing block element for fixed-position descendants r=dholbert

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e9c89f8c95dd
Suppress `column-span:all` for descendants of a containing block element for fixed-position descendants r=dholbert

Comment 10

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

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/33412 for changes under testing/web-platform/tests

Comment 11

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/e9c89f8c95dd

Comment 12

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

Upstream PR merged by moz-wptsync-bot