Bug 245025

Summary: [css-grid] span i should not serialize to span 1 i
Product: WebKit Reporter: Tim Nguyen (:ntim) <ntim>
Component: CSSAssignee: Matt Woodrow <mattwoodrow>
Status: RESOLVED FIXED    
Severity: Normal CC: mattwoodrow, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
See Also: https://github.com/web-platform-tests/wpt/pull/36010
Bug Depends on:    
Bug Blocks: 204611    

Comment 1 Radar WebKit Bug Importer 2022-09-10 06:22:11 PDT
<rdar://problem/99778041>
Comment 2 Matt Woodrow 2022-09-21 19:06:49 PDT
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.
Comment 3 Matt Woodrow 2022-09-21 19:23:06 PDT
Pull request: https://github.com/WebKit/WebKit/pull/4587
Comment 4 EWS 2022-09-23 23:32:08 PDT
Committed 254821@main (fc4a525dc150): <https://commits.webkit.org/254821@main>

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