Intent to Ship: CSS quotes property - support 'auto' value

[Rune Lillesveen]

Contact emails

fut...@chromium.org

Specification

https://www.w3.org/TR/css-content-3/#quotes

TAG review

Simple change to established CSS standard, shipped in Firefox, no TAG review should be necessary.

Summary

Support 'auto' for the 'quotes' property. CSS2 specified the initial value for 'quotes' as UA dependent, but WebKit and Blink currently return an invalid value (empty string) for computed style which will not round-trip. Setting it to the empty string will remove the declaration instead of setting it to the initial value. css-content-3 instead uses an 'auto' keyword for the default UA behavior.

Motivation

Fix brokenness in current implementation and align with spec and Firefox.

Risks

Interoperability and Compatibility

The 'auto' value was shipped in Firefox 70.

Interop

Improved with Firefox, worse with WebKit, but considering the current uselessness of the invalid value returned by Blink/WebKit, the current interop is not really that valuable.

Compat

• Setting the value to initial does not change, the behavior of auto is the same as with the current internal initial representation.
• Current sites adding a declaration with 'auto' will change behavior to what happens in Firefox. Not likely that this is common.
• Firefox got a report for the interop issue according to: https://bugs.chromium.org/p/chromium/issues/detail?id=990557#c8

Expected low risk for both interop and compat.

Gecko: Shipped/Shipping (https://developer.mozilla.org/en-US/docs/Web/CSS/quotes#Browser_compatibility) Shipped in Firefox 70 according to MDN.

WebKit: No signal Not responded to reported issue: https://bugs.webkit.org/show_bug.cgi?id=215646

Web developers: No signals

Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)?

Yes

Is this feature fully tested by web-platform-tests?

Yes

• http://wpt.fyi/css/css-content/inheritance.html
• http://wpt.fyi/css/css-content/quotes-033.html
• http://wpt.fyi/css/css-typed-om/the-stylepropertymap/properties/quotes.html

Tracking bug

https://crbug.com/990557

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/4922661488558080

This intent message was generated by Chrome Platform Status.

[Domenic Denicola]

Does this change include changing the default user agent stylesheet to no longer match https://html.spec.whatwg.org/#quotes? If so, it would be ideal to get that spec changed; I asked the CSSWG about that some months ago in https://github.com/w3c/csswg-drafts/issues/4074#issuecomment-628161036 but did not get a response.

[Emilio Cobos Álvarez]

On 8/20/20 4:35 PM, Domenic Denicola wrote:

> Does this change include changing the default user agent stylesheet to no longer match https://html.spec.whatwg.org/#quotes? If so, it would be ideal to get that spec changed; I asked the CSSWG about that some months ago in https://github.com/w3c/csswg-drafts/issues/4074#issuecomment-628161036 but did not get a response.

Yeah, no browser behaves like the HTML spec says. Such an stylesheet
would be extremely inefficient, so the spec should just be changed to
maybe define what quotes: auto does for a given language.

 -- Emilio

[Rune Lillesveen]

If I read the meeting notes in the github issue correctly, it sounds like the intention was to change the UA sheet in HTML to 'auto' and possibly specify the 'auto'-behavior in CSS, not tied to HTML specifically.

[Rune Lillesveen]

... and since 'auto' is the initial value, it might not be necessary with UA styles at all?

 

[Domenic Denicola]

From: Rune Lillesveen <fut...@chromium.org>

> If I read the meeting notes in the github issue correctly, it sounds like the intention was to change the UA sheet in HTML to 'auto' and possibly specify the 'auto'-behavior in CSS, not tied to HTML specifically.
>
> ... and since 'auto' is the initial value, it might not be necessary with UA styles at all?

Yes, that might be the case. I just wish someone would engage with the HTML Standard on this, or at least with the HTML Standard's editors, so that we could have the UA stylesheet be correct, and have the specs match what you're proposing to ship here.
 

[Rune Lillesveen]

Created pull request: https://github.com/whatwg/html/pull/5868

[Rune Lillesveen]

On Thu, Aug 20, 2020 at 2:30 PM Rune Lillesveen <fut...@chromium.org> wrote:

Interoperability and Compatibility

The 'auto' value was shipped in Firefox 70.

Interop

Improved with Firefox, worse with WebKit, but considering the current uselessness of the invalid value returned by Blink/WebKit, the current interop is not really that valuable.

Compat

• Setting the value to initial does not change, the behavior of auto is the same as with the current internal initial representation.
• Current sites adding a declaration with 'auto' will change behavior to what happens in Firefox. Not likely that this is common.
• Firefox got a report for the interop issue according to: https://bugs.chromium.org/p/chromium/issues/detail?id=990557#c8

Expected low risk for both interop and compat.

Gecko: Shipped/Shipping (https://developer.mozilla.org/en-US/docs/Web/CSS/quotes#Browser_compatibility) Shipped in Firefox 70 according to MDN.

WebKit: No signal Not responded to reported issue: https://bugs.webkit.org/show_bug.cgi?id=215646

Updated info for WebKit: Emilio landed a fix for the mentioned issue, so all three engines should be aligned if this ships in Chrome.

[Daniel Bratell]

LGTM1

/Daniel

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[Yoav Weiss]

LGTM2

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[Chris Harrelson]

LGTM3

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