[Math Processing Error] with mathvariant

[fred-wang]

The mathvariant attribute values for arabic scripts as well as unknow values can cause a [Math Processing Error].

The MathJax testsuite contains tests here:

MathMLToDisplay/Characters/Variants/

They are taken from the MathML test suite, but don't test the attributes mentioned above. Here is a testcase:

<math><mi mathvariant="inital">x</mi></math>
<math><mi mathvariant="tailed">x</mi></math>
<math><mi mathvariant="looped">x</mi></math>
<math><mi mathvariant="stretched">x</mi></math>
<math><mi mathvariant="unknown">x</mi></math>

[fred-wang]

The error is:

"variant is undefined"
file "http://cdn.mathjax.org/mathjax/latest/unpacked/jax/output/HTML-CSS/jax.js"
line 1877

[fred-wang]

HTMLgetVariant (and SVGgetVariant) does not seem to do anything to handle the arabic scripts or invalid mathvariants. I guess the error happens when the function arrives at return HTMLCSS.FONTDATA.VARIANT[variant] where the entry is undefined. Would it make sense to verify at the beginning of the function whether the mathvariant attribute value is valid and to fallback values.mathvariant to "normal" otherwise?

[fred-wang]

Crashtests/issue363.html

=> In testsuite

[fred-wang]

I just pushed a fix for this in my issue363 branch. I also added more tests to the test suite.

[dpvc]

I've merged your issue363 branch into develop.