2008537 - position-area should implicitly apply correct justify-self value

Status: RESOLVED FIXED

(Core :: Layout: Positioned, defect)

Description

[Jake Archibald [:jakea]]

Attachment: Demo

https://codepen.io/jaffathecake/pen/bNVbQyp?editors=1100

Press the button to show the popover. It should not overflow the sides of the viewport.

https://drafts.csswg.org/css-anchor-position-1/#position-area-alignment

Comment 1

[Jake Archibald [:jakea]]

Marking as dev-doc-needed assuming https://github.com/mdn/browser-compat-data/pull/28761 lands and we should mark ourselves as no-longer-partial.

Comment 2

[Jonathan Kew [:jfkthame]]

It looks like we do try to use the appropriate justify-self value (anchor-center) here, but what we fail to do is to treat it as a "safe" alignment by default.

Adding an explicit justify-self: anchor-center to the #footnote element fixes the behavior. But with the initial value of auto, although that gets resolved to anchor-center, the "raw" value being auto means that we skip the alignment fixup here.

A possible fix may be to exempt a resolved value of anchor-center from the condition here, as the "legacy behavior" that code wants to preserve won't be relevant to anchor-positioning anyhow.

Comment 3

[Jonathan Kew [:jfkthame]]

Attachment: Bug 2008537 - Use "safe" behavior by default when applying implicit anchor-center alignment. r=#anchor-pos

Comment 4

[Jonathan Kew [:jfkthame]]

Attachment: Bug 2008537 - Add a simple reftest to confirm default anchor-center justification is 'safe'. r=#anchor-pos

This fails in current Nightly (without the patch here). It renders as expected in Chrome.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/326431509879
https://hg.mozilla.org/integration/autoland/rev/133b0f2e5db4
Use "safe" behavior by default when applying implicit anchor-center alignment. r=layout-anchor-positioning-reviewers,layout-reviewers,emilio,dshin
https://github.com/mozilla-firefox/firefox/commit/819f2165c3c9
https://hg.mozilla.org/integration/autoland/rev/bea6b109a5e4
Add a simple reftest to confirm default anchor-center justification is 'safe'. r=layout-anchor-positioning-reviewers,emilio

Comment 6

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

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/56992 for changes under testing/web-platform/tests

Comment 7

[Serban Stanca [:SerbanS]]

https://hg.mozilla.org/mozilla-central/rev/133b0f2e5db4
https://hg.mozilla.org/mozilla-central/rev/bea6b109a5e4

Comment 8

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

Upstream PR merged by moz-wptsync-bot

Comment 9

[Emilio Cobos Álvarez [:emilio]]

Attachment: Bug 2008537 - Use "safe" behavior by default when applying implicit anchor-center alignment.

Original Revision: https://phabricator.services.mozilla.com/D277892

Comment 10

[Emilio Cobos Álvarez [:emilio]]

Attachment: Bug 2008537 - Add a simple reftest to confirm default anchor-center justification is 'safe'.

This fails in current Nightly (without the patch here). It renders as expected in Chrome.

Original Revision: https://phabricator.services.mozilla.com/D277893

Comment 11

[Dave Letorey]

Related issues and pull requests

• Firefox 148 Release PR
• BCD PR

Comment 12

[Pulsebot]

https://github.com/mozilla-firefox/firefox/commit/55f70a5d7fb0
https://hg.mozilla.org/releases/mozilla-release/rev/52cc9f58dad9
https://github.com/mozilla-firefox/firefox/commit/3674bb587b64
https://hg.mozilla.org/releases/mozilla-release/rev/a73eba95e1b9