1831829 - Print Preview freezing tab when loading a column layout based document

Status: VERIFIED FIXED

(Core :: Print Preview, defect)

Description

[Vlad Lucaci, Thunderbird QA (:vlucaci)]

Found in

• 114.0a1 (2023-05-07)

Affected versions

• 113.0-build2
• 114.0a1 (2023-05-07)

Tested platforms

• Affected platforms: macOS 13, Ubuntu 22, Windows 11
• Unaffected platforms: none

Steps to reproduce

1. Launch FF.
2. Go to this website
3. Print Preview (CTRL+P)

Expected result

• The webpages is print previewed without any issues.

Actual result

• The page does not load inside print preview and the tab becomes unresponsive

Regression range

• First bad: 2022-08-10
• Last good: 2022-08-09
• Pushlog: autoland:pushlog
• Potentially regressed by: 793686

Additional notes

• This issue has been investigated and submitted as part of this Support Question.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

:TYLin, since you are the author of the regressor, bug 793686, could you take a look?

For more information, please visit BugBot documentation.

Comment 2

[Ting-Yu Lin [:TYLin] (PST, UTC-8)]

Attachment: testcase1.zip (snapshot of the website, not reduced)

I can reproduce this issue with the saved website. I think the column-balancing algorithm is trapped in an infinite loop in print preview because of some break-inside:avoid elements.

Comment 3

[Ting-Yu Lin [:TYLin] (PST, UTC-8)]

Attachment: Bug 1831829 - Consider multicol container in paginated context when setting mIsTopOfPage bit.

A top-level multicol in a paginated context can be fragmented. We should use the
same logic to set the mIsTopOfPage bit as if the multicol is a nested one.

WARNING: loading the testcase without this patch can trap Firefox in an infinite
loop.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/1620189277fc
Consider multicol container in paginated context when setting mIsTopOfPage bit. r=emilio

Comment 5

[Cristian Tuns]

https://hg.mozilla.org/mozilla-central/rev/1620189277fc

Comment 6

[BugBot [:suhaib / :marco/ :calixte]]

The patch landed in nightly and beta is affected.
:TYLin, is this bug important enough to require an uplift?

• If yes, please nominate the patch for beta approval.
• If no, please set status-firefox114 to wontfix.

For more information, please visit BugBot documentation.

Comment 7

[Ting-Yu Lin [:TYLin] (PST, UTC-8)]

Comment on attachment 9332532 [details]
Bug 1831829 - Consider multicol container in paginated context when setting mIsTopOfPage bit.

Beta/Release Uplift Approval Request

• User impact if declined: Browser can freeze in printing or printing preview if the page cotains multi-column layout and break-inside:avoid elements.
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): It's low risky because it's a one line change (modulo the comment update) and the code path is the same as nested multi-column layout
• String changes made/needed: None
• Is Android affected?: Yes

Comment 8

[Pascal Chevrel:pascalc]

Comment on attachment 9332532 [details]
Bug 1831829 - Consider multicol container in paginated context when setting mIsTopOfPage bit.

Approved for 114 beta 4, thanks.

Comment 9

[Pascal Chevrel:pascalc]

https://hg.mozilla.org/releases/mozilla-beta/rev/a63faf7294d9

Comment 10

[Vlad Lucaci, Thunderbird QA (:vlucaci)]

Hello,

Confirming this issue as verified fixed on 114.0b4 (20230514175823) and 115.0a1 (20230514213610) using macOS 13, Ubuntu 22 and Windows 11.

Comment 11

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

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/40215 for changes under testing/web-platform/tests

Comment 12

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

Upstream PR merged by moz-wptsync-bot