[css-lists-3] counter(name, none) should be invalid

[fantasai]

In CSS2, counter(name, none) and counters(name, "string", none) were both invalid, as none was not allowed in counters(). See definition of counter functions in CSS2

In the CSS Lists Level 3 drafts, it was allowed, but it caused the function to return the empty string.

Meanwhile, in Chrome and Firefox, none is valid, and it represents a counter style that returns the empty string (which in counters(), is not the same thing as simply returning the empty string). Testcase

Wrt the css-lists-3 behavior, I can't think of any use case. If you want the empty string, you can just write "". As for the behavior implemented in Chrome and Firefox for counters(), it seems really odd, as it just generates a series of (n-1) copies of a string for a counter nesting depth of n?

I'm updating the css-lists-3 spec to match CSS2, because that's our reference spec for these features and we're supposed to sync with it. Filing this issue to track that and in case anyone wants to argue for matching Chrome & Firefox.

CC @MatsPalmgren @dbaron @tabatkins @jensimmons @LeaVerou

[css-meeting-bot]

The CSS Working Group just discussed counter(name, none) should be invalid.

The full IRC log of that discussion

<fantasai> Topic: counter(name, none) should be invalid
<fantasai> github: https://github.com//issues/4163

[css-meeting-bot]

The CSS Working Group just discussed counter(name, none) should be invalid, and agreed to the following:

• RESOLVED: Update to match 2.1 and make counter(name, none) invalid

The full IRC log of that discussion

<dael> Topic: counter(name, none) should be invalid
<dael> github: https://github.com//issues/4163
<dael> fantasai: If you say counter(name,counter-style) it represents list using that. There is a none value that's value of list-style-type. Some impl think that's valid as a counter style. CSS 2.1 forbids that. I updated spec to match css2.1
<dael> fantasai: If people disagree and think counter(name, none) should be valid we can reconsider
<dael> TabAtkins: I wrote that near 10 years ago. Can't comment on [missed] so whatever
<TabAtkins> s/[missed]/justification
<dael> fantasai: Objections to updating spec to match 2.1?
<TabAtkins> No objection.
<dael> RESOLVED: Update to match 2.1 and make counter(name, none) invalid

[faceless2]

I realise this is closed and CSS 2.1 is long since outdated, but just wanted to note that although "none" wasn't allowed in CSS 2, the final line of the example at https://www.w3.org/TR/CSS21/generate.html#counter-styles has

P:before         { content: counter(p, none) }

and the text above that example explicitly states "All the styles are allowed, including 'disc', 'circle', 'square', and 'none'."

[SebastianZ]

Yes, it looks like the resolution here actually caused the inconsistency between the specs. 😅 See also the discussion in #5795.

Sebastian