Added deprecation warning for old-style urlconfigs in plugins

src/pretix/multidomain/maindomain_urlconf.py

@@ -1,4 +1,5 @@
 import importlib.util
+import warnings
 
 from django.apps import apps
 from django.conf.urls import include, url
@@ -31,6 +32,9 @@ for app in apps.get_app_configs():
                     url(r'^(?P<organizer>[^/]+)/(?P<event>[^/]+)/', include(urlmod.event_patterns, namespace=app.label))
                 )
         elif importlib.util.find_spec(app.name + '.maindomain_urls'):
+            warnings.warn('Please put your config in an \'urls\' module using the urlpatterns and event_patterns '
+                          'attribute. Support for maindomain_urls in plugins will be dropped in the future.',
+                          DeprecationWarning)
             urlmod = importlib.import_module(app.name + '.maindomain_urls')
             raw_plugin_patterns.append(
                 url(r'', include(urlmod, namespace=app.label))

src/pretix/multidomain/subdomain_urlconf.py

@@ -1,9 +1,8 @@
-import importlib
 import importlib.util
+import warnings
 
 from django.apps import apps
 from django.conf.urls import include, url
-
 from pretix.presale.urls import (
     event_patterns, locale_patterns, organizer_patterns,
 )
@@ -26,6 +25,9 @@ for app in apps.get_app_configs():
                     url(r'^(?P<event>[^/]+)/', include(urlmod.event_patterns, namespace=app.label))
                 )
         elif importlib.util.find_spec(app.name + '.subdomain_urls'):
+            warnings.warn('Please put your config in an \'urls\' module using the event_patterns '
+                          'attribute. Support for subdomain_urls in plugins will be dropped in the future.',
+                          DeprecationWarning)
             urlmod = importlib.import_module(app.name + '.subdomain_urls')
             raw_plugin_patterns.append(
                 url(r'', include(urlmod, namespace=app.label))