Comment 13 for bug 1613901

The "fix" in WebOb is going to be checking for UnicodeDecodeError and turning that into an URLDecodeError. There would still be a requirement for something upstream of the Request object to catch the exception and properly send it out.

URLDecodeError will be a sub-class of UnicodeDecodeError and HTTPBadRequest, so that it is a valid WebOb exc.WSGIHTTPException and thus can be used as a response object...

There is no direct fix that will suddenly handle this case directly, code that touches PATH and other such variables will simply raise a better exception than a generic UnicodeDecodeError.