1151201 - [css-grid] Update parsing of 'auto' in track-sizing functions to latest version of the spec.

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, defect)

Description

[Mats Palmgren (inactive)]

The Grid spec has changed <track-breadth>.  This is the OLD spec:
http://www.w3.org/TR/2014/WD-css-grid-1-20140513/#typedef-track-list
Note that 'auto' is a value of <track-size> there, not <track-breadth>.
And that 'auto' is defined as 'minmax(min-content, max-content)'. 

The latest spec has moved 'auto' from <track-size> to <track-breadth>:
http://dev.w3.org/csswg/css-grid/#typedef-track-list
which means it can now occur inside 'minmax()'.
And 'auto' now means 'minmax(auto,auto)', IIUC.

The CSSWG resolution is here:
https://lists.w3.org/Archives/Public/www-style/2015Jan/0269.html
(at line ~213)

  fantasai: Next is about minimum size of grid tracks.
  fantasai: In the Grid spec, if you have an auto or flex-sized
            track, you use the largest of the min-contents of the
            things in the track as the "minimum size" of the track,
            and then grow it or flex it from there.
  fantasai: This doesn't work well for items that have a specified
            minimum size.
  fantasai: We have a min-*:auto value from Flexbox. The idea is to
            have Grid behave the same way.
  fantasai: Default behavior would stay the same, due to "auto", but
            let people override.
  fantasai: This allows "auto" in minmax() - minmax(auto, foo) means
            "use the specified min-* property value", and that
            "auto" on its own expands to "minmax(auto, auto)".

  plinss: Seems fine, but it look like there's a few subtleties I
          haven't wrapped my head around.
  fantasai: I had Peter Salas look over the algorithm, and made some
            fixes. I think the algorithm ends up fine.
  plinss: Any implementors have any opinions?
  Rossen: We were part of the discussion, and were fine with it.

  RESOLVED: Allow "auto" in minmax(), have it look at
            min-width/height for value, using same "auto" behavior
            as flexbox

Comment 1

[Mats Palmgren (inactive)]

Attachment: fix

Comment 2

[Mats Palmgren (inactive)]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=2461622df984

Comment 3

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/21fa8192f848

Comment 4

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/21fa8192f848