[css-grid] What track sizes match the concept of "intrinsically-sized track" ?

[javifernandez]

The inline-axis and block-axis alignment sections have the following statement:

https://drafts.csswg.org/css-grid/#row-align

If baseline alignment is specified on a grid item whose size in that axis depends on the size of an intrinsically-sized track (whose size is therefore dependent on both the item’s size and baseline alignment, creating a cyclic dependency), that item does not participate in baseline alignment, and instead uses its fallback alignment.

I'm not sure whether some possible values of the track sizing functions may or not produce an intrinsically-sized track. So, I'll collect some cases here that I think they match and other I'd have doubts;

1. auto -> minmax(auto, auto): yes
2. min-content -> minmax(min-content, max-content): yes
3. fit-content -> minmax(auto, fit-content): yes
4. max-content -> minmax(max-content, max-content): yes
5. 1fr -> minmax(auto, 1fr): ??
6. minmax(auto, 20px): yes
7. minmax(20x, auto): yes
8. minmax(min-content, 20px): yes
9. minmax(20px, min-content): yes
10. minmax(20px, 1fr): ??

Basically, in the Chrome and Webkit implementation we are considering that any content-sized track (I'll fill a new issue about this term too) will produce intrinsically-sized tracks. Additionally, we consider a track as content-sized if either its min-sizing function or its max-sizing function is a content-sized value (auto, min-content or max-content).

Finally, my doubts regarding the flex tracks are related to their dependency with the available size, which will come from the grid container's inline and block size. We assume in both, Chrome and WebKit that a flex track in a indefinite sized container should be considered as content-sized. I couldn't find in the spec where this is specified; maybe we should if it's not the case. I'll file a new issue about this if it's worth discussing it.

I've got more questions, which may be related with this one. However, I'll fill separate issues for now; we can merge then if we think all of them are part of the same issue.

[fantasai]

Wrt examples, 5=yes, 10=no.

[javifernandez]

What about case 10 in a grid with indefinite size ? Shouldn't we consider this track as intrinsically sized according to the following statement ?

https://drafts.csswg.org/css-grid/#fr-unit

When the available space is infinite (which happens when the grid container’s width or height is indefinite), flex-sized grid tracks are sized to their contents while retaining their respective proportions.

[tabatkins]

Reviewing the spec, it looks like we didn't consider the interaction of baseline alignment and fr values in indefinitely-sized containers. I think Chrome/WebKit's current behavior, of treating such tracks as intrinsically-sized and thus triggering fallback alignment for extrinsically-sized baseline-aligned items, is reasonable.

We should clarify the spec on this point, and also how baseline alignment is applied in fr tracks with indefinite free space.

[fantasai]

Agenda+ for review. (I don't think this is controversial, but it is a substantive change.)