1588566 - [wpt-sync] Sync PR 19677 - The block-offset of a spanner may affect layout.

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, task, P4)

Description

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

Sync web-platform-tests PR 19677 into mozilla-central (this bug is closed when the sync is complete).

PR: https://github.com/web-platform-tests/wpt/pull/19677
Details from upstream follow.

Morten Stenshorne <[e-mail]> wrote:

The block-offset of a spanner may affect layout.

We already had code that copied to the block-offset from the spanner
placeholder to the actual spanner layout object, but we also need to
make sure that it actually gets laid out.

See test: In the initial layout pass we'd set the block-size of the
first column row (with the empty DIC) to the block-size of the multicol
container. Then we'd bump into the spanner, and realize that this
block-size would't do, since we need to balance columns in front of a
spanner. Because of this initial block-size of the column row, the
initial layout pass of the spanner would put the spanner below that,
tricking the machinery into believing that we need a break inside the
spanner. In the next layout pass the block-size of the column row would
be corrected, and also the position of the spanner. But we wouldn't
re-lay out, and thus incorrectly keeping a pagination strut in the
middle of the spanner.

Bug: 1006249
Change-Id: If7ec10389ba5f6e78d9ecb5fd4ad7fd113c128bb
Reviewed-on: https://chromium-review.googlesource.com/1859977
WPT-Export-Revision: a60d1f230fbbc6b6955764ce9ce8fb0060825d71

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=57cbe9b09bc74000ed9247a2d6b51ed265830fb5

Comment 2

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

## GitHub CI Results
wpt.fyi [PR Results](https://wpt.fyi/results/?sha=1452217cb6ba183bccbcfbc8c75a87a0e2c65385&label=pr_head) [Base Results](https://wpt.fyi/results/?sha=1452217cb6ba183bccbcfbc8c75a87a0e2c65385&label=pr_base)

Ran 1 tests

### Firefox
  PASS: 1

### Chrome
  FAIL: 1

### Safari
  PASS: 1

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/2fc47e585a2d
[wpt PR 19677] - The block-offset of a spanner may affect layout., a=testonly

Comment 4

[Alexandru Michis [:malexandru]]

https://hg.mozilla.org/mozilla-central/rev/2fc47e585a2d