1448248 - Implement CSS attr(<attr-name>, <attr-fallback>)

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, enhancement, P3)

Description

[Sebastian Zartner [:sebo]]

The CSS Values and Units Module Level 3 extends the attr() function to optionally specify a fallback value, which is used if the named attribute is missing, or its value cannot be parsed into the given type or is invalid/out-of-range for the property.

This bug is meant to implement the basic functionality of the fallback value for the case the attribute is missing.

Sebastian

Comment 1

[Gérard Talbot]

Tests

background: attr(data-test color);
http://w3c-test.org/css/css-values/attr-color-valid.html

width: attr(data-test length);
http://w3c-test.org/css/css-values/attr-length-valid-zero-nofallback.html

width: attr(data-test length);
http://w3c-test.org/css/css-values/attr-length-valid.html

width: attr(data-test px);
http://w3c-test.org/css/css-values/attr-px-valid.html

Comment 2

[Oliver Medhurst [:canadahonk]]

Attachment: Bug 1448248 - Implement CSS attr() fallback

Implemented support for a fallback in CSS attr funcs
(attr(<attr-name>, <attr-fallback>))

Spec: https://drafts.csswg.org/css-values-5/#attr-notation

WIP. Todo:

• Parse fallback into variable
• Use fallback in C++
• Add WPT tests

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a14395d9ad06
Implement CSS attr() fallback r=emilio

Comment 4

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

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/42079 for changes under testing/web-platform/tests

Comment 5

[Iulian Moraru]

https://hg.mozilla.org/mozilla-central/rev/a14395d9ad06

Comment 6

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

Upstream PR merged by moz-wptsync-bot

Comment 7

[Oliver Medhurst [:canadahonk]]

Release Note Request (optional, but appreciated)
[Why is this notable]: New CSS feature supported
[Affects Firefox for Android]: Yes
[Suggested wording]: The CSS attr() function now supports a fallback parameter (eg attr(foobar, "Default value")). First browser to implement, and ship.
[Links (documentation, blog post, etc)]: None yet.

Comment 8

[Dianna Smith [:diannaS]]

Added to 119 beta release notes (https://www.mozilla.org/en-US/firefox/119.0beta/releasenotes/) as well as the Draft release notes for 119

Comment 9

[Dave Letorey]

• Content PR
• BCD PR