[css-sizing-4] How to parse "contain-intrinsic-size: 10px auto 20px;"

[cbiesinger]

https://www.w3.org/TR/css-sizing-4/#intrinsic-size-override

The grammar allows the length and auto in any order. Therefore, the following is valid:
contain-intrinsic-size: 10px auto 20px;

However, should it be interpreted as contain-intrinsic-width: auto 10px; contain-intrinsic-height: 20px; or as contain-intrinsic-width: 10px; contain-intrinsic-height: auto 20px;?

@fantasai @tabatkins

[tabatkins]

Following up: we just fixed the ordering as auto <length>, since that reflects the importance of the values and solves the parsing issue - 10px auto 20px is thus c-i-width: 10px; c-i-height: auto 20px;.

[Loirooriol]

<length> | auto <length> could be shortened to auto? <length>

[tabatkins]

It can be, yes, but we sometimes separate out clauses like this when the behavior is significantly different and we want to talk about the cases separately.

[cbiesinger]

Thanks, sgtm. I implemented that in https://chromium-review.googlesource.com/c/chromium/src/+/3138514.