[csswg-drafts] Empty row-groups special treatment (#5772)

atotic has just created a new issue for https://github.com/w3c/csswg-drafts:

== Empty row-groups special treatment ==
Empty row-groups are treated differently during layout. Spec does not mention this. The issues I've found are:

1) When is row-group treated as empty? 

Only row-groups with no children are treated as empty. Empty row child, or an abspos child, all trigger non-empty behavior.

2) What is the size of an empty row-group?

external/wpt/css/css-tables/bounding-box-computation-3.html asserts that empty row-group should have width of 0

Chrome 87, FF 83, Safari 13 disagree, the row-group width matches other rows.
Pre-Chrome Edge has width of 0.

Suggestion: standardize empty row-group width to match table's grid, like other rows. This is prevalent implementation, and aligns with CSS behavior for empty blocks.

3) border-spacing and empty row-groups?

```html
    <table border-spacing:10px>
      <tbody></tbody>
      <tbody></tbody>
      <tbody><td>x</td></tbody>
    </table>
```

Chrome 87, Edge 17, Safari 13 do not generate border spacing for empty row groups. FF does.

What is the location of the first tbody? I believe its offsetTop should be 0 (no border spacing), but bounding-box-computation-3.html disagrees. It inserts border spacing before first row-group, even if it is empty. Unless all row-groups are empty, in which case there is no border-spacing.
Suggestion: empty row-groups should not generate any border spacing before or after ever.


Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/5772 using your GitHub account


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Received on Tuesday, 8 December 2020 21:11:09 UTC