id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
31061	Optional URL params crash some view functions.	Claude Paroz	Mariusz Felisiak	"My use case, running fine with Django until 2.2:

URLConf:
{{{
urlpatterns += [
    ...
    re_path(r'^module/(?P<format>(html|json|xml))?/?$', views.modules, name='modules'),
]
}}}

View:
{{{
def modules(request, format='html'):
    ...
    return render(...)
}}}

With Django 3.0, this is now producing an error:
{{{
Traceback (most recent call last):
  File ""/l10n/venv/lib/python3.6/site-packages/django/core/handlers/exception.py"", line 34, in inner
    response = get_response(request)
  File ""/l10n/venv/lib/python3.6/site-packages/django/core/handlers/base.py"", line 115, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File ""/l10n/venv/lib/python3.6/site-packages/django/core/handlers/base.py"", line 113, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)

Exception Type: TypeError at /module/
Exception Value: modules() takes from 1 to 2 positional arguments but 3 were given
}}}"	Bug	closed	Core (URLs)	3.0	Release blocker	fixed			Ready for checkin	1	0	0	0	0	0