[css-animations] animation-name can contain string

[ewilligers]

The computed value for animation-name can contain strings.

For example, the following are valid:
@Keyframes "initial" { ... }
@Keyframes "None" { ... }

The computed value for animation-name
"initial", "None", None
should be
"initial", "None", none

Without quotes, the computed value would not round trip.

[ewilligers]

Proposed WPT

[tabatkins]

Hm. I guess the question is; do we actually preserve this information in the underlying value? An alternative is to always make it an identifier, but serialize as a string when it's the handful of disallowed idents.

I don't have a strong opinion; I'm fine with matching implementations.

[emilio]

See #2435

[tabatkins]

Cool, so that suggests that we should keep the computed value as idents, and just specify that serialization produces strings in a few limited cases.

[birtles]

@ericwilligers I think this PR is no longer correct. If I understand the resolution from #2435 correctly, we no longer want to allow "initial" as an animation-name, for example.

From what I understand, it sounds like the behavior we want is:

1. Accept <string> or <custom-ident> as we currently do.
2. If <string> is one of the CSS-wide keywords or "default" then it is invalid (at parse / variable-resolution time) as per the rules for custom-idents: https://www.w3.org/TR/css-values-3/#custom-idents
3. When serializing, if the value doesn't have whitespace(??) serialize without quotes (i.e. as <custom-ident>), otherwise serialize as <string>. I'm not sure what other cases require quotes or if there is machinery defining this somewhere else? (I looked in CSS Fonts 4 but didn't find anything there.)

[ewilligers]

I missed #2435

RESOLVED: serialize all keyframes as identifiers

This implies we never serialize as strings, so "1" and " " and "initial" and "None" can not be valid keyframe names. I suspect " hello " should either not be a valid keyframe name, or it should serialize as hello.

This PR can be discarded.

[birtles]

This implies we never serialize as strings

I believe that resolution doesn't capture what was actually discussed. Or at least, when I re-read through the minutes my understanding was that we would still serialize as strings when needed. Tab's comment above also seems to suggest that.

[birtles]

3. When serializing, if the value doesn't have whitespace(??) serialize without quotes (i.e. as <custom-ident>), otherwise serialize as <string>. I'm not sure what other cases require quotes or if there is machinery defining this somewhere else? (I looked in CSS Fonts 4 but didn't find anything there.)

Maybe it would just be better to say that anything that can be serialized as a <custom-ident> is serialized as such, and anything else is serialized as a string.

[birtles]

Cancelling review request as per my comments above, I believe this PR doesn't capture the changes discussed in the minutes.

[ewilligers]

Maybe it would just be better to say that anything that can be serialized as a <custom-ident> is serialized as such, and anything else is serialized as a string.

https://jsfiddle.net/ericwilligers/5na1Ldpb/ shows that Firefox computes "Default" "Initial" "None" as Default Initial None; two of these do not round trip and Default should not round trip either.

[ewilligers]

Note also that Firefox preserves '""' as a specified value, but gives none as the computed value.

[upsuper]

Note also that Firefox preserves '""' as a specified value, but gives none as the computed value.

IIRC this is a known bug of Firefox.

[yisibl]

Note also that Firefox preserves '""' as a specified value, but gives none as the computed value.

IIRC this is a known bug of Firefox.

https://bugzilla.mozilla.org/show_bug.cgi?id=1554737