SVG2: `href` must take precedence over `xlink:href` when both are present

[yisibl]

According to the SVG 2 specification, the XLink-based URL reference attributes (such as xlink:href) are deprecated and replaced by the unprefixed href attribute.

The specification explicitly defines the conflict resolution behavior when both attributes are present on the same element:

When the ‘href’ attribute is present in both the XLink namespace and without a namespace, the value of the attribute without a namespace shall be used. The attribute in the XLink namespace shall be ignored.

(Source: SVG 2 – Linking, “Deprecated XLink URL reference attributes”)
https://www.w3.org/TR/SVG2/linking.html

which is not compliant with the SVG 2 specification.

According to the spec, the unnamespaced href attribute must always take precedence when both are present, and xlink:href must be ignored.

This affects elements such as <textPath>, <use>, <image>, <a>, and other elements that accept URL reference attributes.

Demo

<svg width="200" height="200" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
  <defs>
    <rect id="red" x="0" y="0" width="100" height="100" fill="red"/>
    <rect id="green" x="0" y="0" width="100" height="100" fill="green"/>
  </defs>

  <!-- According to SVG 2, href MUST win, so this should be GREEN -->
  <use
    href="#green" xlink:href="#red"
    x="20" y="20" />
</svg>

resvg 0.46.0

Chrome 143/Firefox 149

WPT

w3c/svgwg#1043