2016959 - WPT /css/css-break/out-of-flow-in-multicolumn-012.html after bug 2012842 with layout.abspos.fragmentainer-aware-positioning.enabled=true

Status: RESOLVED FIXED

(Core :: Layout: Positioned, defect)

Description

[Ting-Yu Lin [:TYLin] (PST, UTC-7)]

https://wpt.live/css/css-break/out-of-flow-in-multicolumn-012.html

This test verifies that an absolute containing block's block-size can grow during fragmentation due to break-inside: avoid. That is, the absCB's unfragmented block-size can be smaller than its cumulative block-size after fragmentation. I somewhat expected we might fail in this scenario, so I'm glad we have a testcase that exercises it.

Comment 1

[Ting-Yu Lin [:TYLin] (PST, UTC-7)]

This is probably acceptable and shouldn't block enabling the pref in bug 2002115, unless others feel differently.

Comment 2

[Ting-Yu Lin [:TYLin] (PST, UTC-7)]

I have an idea to fix this. Also, if we introduce a measuring reflow for printing in bug 2009647, this bug must be fixed to prevent https://wpt.live/css/css-page/page-margin-004-print.html from failing.

Comment 3

[Ting-Yu Lin [:TYLin] (PST, UTC-7)]

Attachment: Bug 2016959 - Allow abspos element with auto block-size to have fragmentation-imposed block-size growth. r?dshin,#layout

This patch also prevents WPT /css/css-page/page-margin-004-print.html from
failing when adding a measuring reflow to printing context.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/ac2258bf799a
https://hg.mozilla.org/integration/autoland/rev/7cdbb0c14bb8
Allow abspos element with auto block-size to have fragmentation-imposed block-size growth. r=dshin,layout-reviewers

Comment 5

[agoloman]

https://hg.mozilla.org/mozilla-central/rev/7cdbb0c14bb8

Comment 6

[Iulian Moraru]

https://hg.mozilla.org/mozilla-central/rev/7cdbb0c14bb8