Bug 245025 – [css-grid] span i should not serialize to span 1 i

• Status: RESOLVED
• Resolution: FIXED
• Component: CSS

[Tim Nguyen (:ntim)]

See https://wpt.fyi/results/css/css-grid/parsing/grid-area-computed.html?label=master&label=experimental&product=chrome&product=firefox&product=safari&aligned&view=interop&q=label%3Ainterop-2021-grid

[Radar WebKit Bug Importer]

<rdar://problem/99778041>

[Matt Woodrow]

This test is invalid :(

It's checking that `grid-column-start: span 1 i` round-trips exactly, as does `grid-row-start: span i`.

The only way to make both of those tests is to preserve whether the '1' was explicitly passed in, and use that to decide how to serialise the computed value, rather than just using the shortest serialisation principle.

Gecko is passing this because they parse an implicit integer as 0, and omit serializing the integer if it's 0. They then covert 0 to 1 at used value time.

The spec for parsing 'span': If the <integer> is omitted, it defaults to 1. Negative integers or zero are invalid.

[Matt Woodrow]

Pull request: https://github.com/WebKit/WebKit/pull/4587

[EWS]

Committed 254821@main (fc4a525dc150): <https://commits.webkit.org/254821@main>

Reviewed commits have been landed. Closing PR #4587 and removing active labels.