[PATCH] Using IncludeFilter can trip assertions in Template.generate

[robinbryce@…]

Using IncludeFilter like this:

Template(source).generate().filter(
    IncludeFilter(TemplateLoader(['']))
    ).render()

will cause an assertion failure in Template.generate. This happens because IncludeFilter is called with no arguments when it is applied by markup.core:Stream.filter.

Utlimately the propogation of the defaults, and pythons rules for kwargs/args processing, conspire to pass None as the first argument to Template.generate.

The attatched patch simply detects this case and treats it as equivelent to calling generate with no arguments.

[cmlenz]

Good catch, thanks!

[cmlenz]

Applied in [218].