[css-grid][css-sizing] min-content size of grid container in block axis

[Loirooriol]

https://drafts.csswg.org/css-sizing/#min-content-block-size says

min-content block size: Equivalent to the max-content block size.

https://drafts.csswg.org/css-grid/#ref-for-min-content says

The max-content size (min-content size) of a grid container is the sum of the grid container’s track sizes (including gutters) in the appropriate axis, when the grid is sized under a max-content constraint (min-content constraint).

So in the block axis it seems CSS Sizing defines the min-content size to be equal to the max-content size, while CSS grid defines them to be different in general.

Usually this is not observable because it's hard to get a min-content size in the block axis, e.g. block-size: min-content behaves as auto. But it's used e.g. in https://drafts.csswg.org/css-flexbox-1/#min-size-auto

The content size suggestion is the min-content size in the main axis

which can be the block axis in a column flex container.

See https://crbug.com/936042 for context. https://jsfiddle.net/9fuL2ecs/

  <div id="flex">
    <div id="grid">
      <div id="item1"></div>
      <div id="item2"></div>
    </div>
  </div>

#flex {
  display: flex;
  flex-direction: column;
  height: 100px;
  overflow: hidden;
}
#grid {
  flex: 1 1 0;
  display: grid;
  grid-template-rows: minmax(0, 100px) 100px;
}
#item1 {
  height: 100px;
  width: 100px;
  background: green;
}
#item2 {
  background: red;
}

Chromium used to let the first row be 0px tall, but currently it behaves like Firefox and min-height:auto on the flex item lets the 1st row grow to 100px and no red is shown. Is this right?

[tabatkins]

Looks like this has been fixed since it was reported, the definition of min-content block size is now:

In general, and definitely for block containers, tables, and inline boxes, this is equivalent to the max-content block size.

which allows for specific layout algos to override the "in general" wording.

[Loirooriol]

Seems fine, though it's unfortunate that Chromium already had this behavior but changed because of the old css-sizing. I hope changing back will still be web compatible.