Backend-agnostic debug information on template loading failures
|Ready for checkin
|Patch needs improvement:
Currently ExceptionReporter.get_traceback_data() contains a special case for exceptions raised when a template cannot be found.
It retries loading the template with each template loader to figure out which paths were tried. Since the multiple templates engines refactor, this still works, but only if there's only one Django templates engine configured.
This logic should be embedded in the template engine. Third-part engines should have access to similar functionality through a public API.
Some ideas were brought up in this django-developers discussion.