Bug 264876 – [SVG2] getPointAtLength should throw exception when not in Active Document for SVGPathElement

• Component: SVG
• Status: REOPENED

[Ahmad Saleem]

Hi Team,

While looking through SVG2 Web-spec (around IDL interfaces), I noticed that we need to through exception when 'getPointAtLength' is not in renderable document.

SVG Web-Spec: https://svgwg.org/svg2-draft/types.html#InterfaceSVGGeometryElement

"The getPointAtLength method is used to return the point at a given distance along the path. When getPointAtLength(distance) is called, the following steps are run:

If current element is a non-rendered element, and the UA is not able to compute the total length of the path, then throw an InvalidStateError.'

So I think we need to update our both 'Legacy' and 'LBSE' RenderShape call sites for 'getPointAtLength' to be 'ExceptionOr<>' and throw an error.

WebKit Source: https://searchfox.org/wubkat/rev/7753b1fdea4b4605b4851dec61966b8b7247302a/Source/WebCore/rendering/svg/RenderSVGShape.cpp#312

Just wanted to raise so we can track and fix it.

Thanks!

[Ahmad Saleem]

It might progress this failing WPT test case:

https://wpt.fyi/results/svg/types/scripted/SVGGeometryElement.getPointAtLength-03.svg?label=master&label=experimental&aligned=&q=getpointatlength

"When SVGGeometryElement.getPointAtLength is called with an element that is not in the document, either succeed or throw exception with SVGPathElement"

[Radar WebKit Bug Importer]

<rdar://problem/118720630>

[EWS]

Committed 274308@main (9f2facf9ef6d): <https://commits.webkit.org/274308@main>

Reviewed commits have been landed. Closing PR #23699 and removing active labels.

[Ahmad Saleem]

Reverted 274929@main