1896062 - New wpt failures in /css/css-ruby/pseudo-first-line.html (Firefox fails to honor `ruby-position` in the `::first-line` pseudo)

Status: NEW

(Core :: Layout: Ruby, defect)

Description

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

Syncing wpt PR 46196 found new untriaged test failures in CI

Tests Affected

New Tests That Don't Pass

• /css/css-ruby/pseudo-first-line.html [wpt.fyi]: FAIL (Chrome: FAIL, Safari: PASS)

CI Results

Gecko CI (Treeherder)
GitHub PR Head

Notes

These updates will be on mozilla-central once bug 1896048 lands.

Note: this bug is for tracking fixing the issues and is not
owned by the wpt sync bot.

This bug is linked to the relevant tests by an annotation in
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If this bug is split into multiple bugs, please also update the
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Comment 1

[Daniel Holbert [:dholbert] (PTO until 2/24)]

Testcase:
https://wpt.live/css/css-ruby/pseudo-first-line.html
Reference case:
https://wpt.live/css/css-ruby/pseudo-first-line-ref.html

We seem to be ignoring the ruby-position styling on the first line. The first line's ruby element is expected to inherit that and put the annotation below the line, but instead it puts the annotation above the line.

Safari: PASS

Safari doesn't meaningfully pass; they don't support unprefixed ruby-position at all, per https://caniuse.com/?search=ruby-position . The testcase and reference case both use that property (and it's the relevant thing being tested), so Safari's implementation is just passing-by-not-having-the-feature.

If I swap to their prefixed version (-webkit-ruby-position: after) in the testcase and reference case, they fail in the same way that we do (the testcase still puts the annotation above the line, when it should in fact put it below the line).