Bug 308017 – SVG patternTransform.baseVal.clear() should cause patternTransform to be ignored

• Status: NEW
• Component: SVG

[Karl Dubost]

http://wpt.fyi/svg/pservers/scripted/pattern-transform-clear.svg
Go to http://wpt.live/svg/pservers/scripted/pattern-transform-clear.svg

PASS in Firefox and Chrome
FAIL in Safari

The markup is 

<?xml version="1.0" encoding="UTF-8"?>
<svg xmlns="http://www.w3.org/2000/svg" xmlns:h="http://www.w3.org/1999/xhtml">
  <title>SVG Paint Servers: Clear should cause patternTransform to be ignored.</title>
  <metadata>
    <h:link rel="help" href="https://svgwg.org/svg2-draft/pservers.html#PatternElementPatternTransformAttribute"/>
    <h:link rel="match" href="../reftests/reference/green-100x100.svg"/>
  </metadata>
  <pattern id="p1" patternTransform="scale(2)"/>
  <pattern id="p" href="#p1" viewBox="0 0 50 50" patternTransform="scale(1)" width="100%" height="100%">
    <rect fill="red" width="50" height="50"/>
    <rect fill="green" width="25" height="25"/>
  </pattern>
  <rect fill="url(#p)" width="100" height="100"/>
  <script><![CDATA[
    document.getElementById("p").patternTransform.baseVal.clear();
  ]]></script>
</svg>


SVGTransformList is defined as
https://w3c.github.io/svgwg/svg2-draft/coords.html#InterfaceSVGTransformList

[Exposed=Window]
interface SVGTransformList {

  readonly attribute unsigned long length;
  readonly attribute unsigned long numberOfItems;

  undefined clear();
  SVGTransform initialize(SVGTransform newItem);
  getter SVGTransform getItem(unsigned long index);
  SVGTransform insertItemBefore(SVGTransform newItem, unsigned long index);
  SVGTransform replaceItem(SVGTransform newItem, unsigned long index);
  SVGTransform removeItem(unsigned long index);
  SVGTransform appendItem(SVGTransform newItem);
  setter undefined (unsigned long index, SVGTransform newItem);

  // Additional methods not common to other list interfaces.
  SVGTransform createSVGTransformFromMatrix(optional DOMMatrix2DInit matrix = {});
  SVGTransform? consolidate();
};


The clear() method is defined as:
https://w3c.github.io/svgwg/svg2-draft/types.html#__svg__SVGNameList__clear


> The clear method is used to remove all items in the list. When clear() is called, the following steps are run:
> 
> 1. If the list is read only, then throw a NoModificationAllowedError.
> 2. Detach and then remove all elements in the list.
> 3. If the list reflects an attribute, or represents the base value of an object that reflects an attribute, then reserialize the reflected attribute.

[Karl Dubost]

This is also failing with LBSE. http://wpt.live/svg/pservers/scripted/pattern-transform-clear.svg

[Radar WebKit Bug Importer]

<rdar://problem/170518953>

[Karl Dubost]

Pull request: https://github.com/WebKit/WebKit/pull/58833