svg symbol id fails with percent-encoded symbols

[Erik Demaine]

Attached is a simple example of SVG that uses percent-encoded symbols in a <symbol id>. Inkscape ignores the object upon import. Changing the <symbol id> (and corresponding <use xlink:href>) to an ASCII string like "space" causes the example to work (produce a black square in the middle of the canvas).

I was originally using 0.91.1, but tested again on 0.92.2 and found the same behavior.

As far as I can tell, <symbol id>s should follow the IRI spec of https://tools.ietf.org/html/rfc3987 which allows percent-encoded characters.

[Jonathan Hofinger (jhofinger)]

Nope, that's not valid. Browsers also don't render the file. That's because
Additional requirements apply in order for the ‘id’ attribute to be valid in XML documents, as defined in the specification for the relevant version of XML. A stand-alone SVG document uses XML 1.0 syntax [xml], which specifies that valid ‘id’ values are XML name tokens (https://www.w3.org/TR/SVG2/struct.html#Core.attrib) and https://www.w3.org/TR/xml/#NT-Name lists the allowed characters for the first and subsequent letters of an ID.

The % sign is U+0025, and can not be included in an ID.

Please reopen at http://inkscape.org/report if you encounter similar issues.

Closed by https://gitlab.com/jhofinger

[Erik Demaine (edemaine)]

Thank you very much for pointing me to the correct spec! I will follow this much more restrictive spec when generating SVG.