1762447 - Tables don't support being fragmented within multicol

Status: NEW

(Core :: Layout: Tables, defect)

Description

[Daniel Holbert [:dholbert]]

Attachment: testcase 1 (expected/correct result would be for both yellow boxes to be split between columns)

(This is a longstanding issue, but I couldn't find a bug on file for it; hence, filing this one.)

Right now, our table layout code doesn't support being fragmented in the context of a multicol/multi-column element. It only supports being fragmentation in paginated/printed output.

It does this by relying on bool isPaginated = aPresContext->IsPaginated(); which includes printed contexts but not multicol:
https://searchfox.org/mozilla-central/rev/625c3d0c8ae46502aed83f33bd530cb93e926e9f/layout/tables/nsTableFrame.cpp#1660

We fail a number of WPT tests as a result of this. (I'll dupe bugs for those test failures here.)

The attached testcase demonstrates this failure, too. The upper yellow box (with a regular block) gets split between columns, but the lower one (for a table / table-cell) does not in Firefox.

Comment 5

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

The severity field for this bug is relatively low, S3. However, the bug has 4 duplicates.
:dholbert, could you consider increasing the bug severity?

For more information, please visit auto_nag documentation.

Comment 6

[Daniel Holbert [:dholbert]]

Dupe count isn't really interesting/relevant here (i.e. this isn't multiple users running up against this and filing bugs).

The dupes are just filed on different WPT tests that happen to exercise this scenario.

Comment 7

[Thomas Wisniewski [:twisniewski]]

Removing the webcompat priority for now, as we don't have any known site breakage right now.