Links with epub:type require href

[mattgarrish]

You can't use epub:type on an inactive link like this:

<a epub:type="glossref">foo</a>

If you do, epubcheck will report:

Error while parsing file: element "a" missing required attribute "href"

I don't know if this occurs often, but it seems like it might be too strict. I'm more worried that people have used it on bad markup patterns like this from the samples: <a epub:type="keyword">bar</a>.

[rdeltour]

Good catch! 👍

I checked the RelaxNG schema and the a element is defined as a combination of 4 elements:

a.elem.phrasing = a.href.elem.phrasing | a.nohref.elem.phrasing
a.elem.flow = a.href.elem.flow | a.nohref.elem.flow

we add the epub:type attribute to the a.attrs attributes, but not all of a.attrs are added to the a element with no href. So when it sees the epub:type attribute, the schema expects to be in one of the a.href.elem.* element, and also expects a href. 🙃

I'll fix the schema when updating the epub:type restrictions.