Fixed #29775 -- Fixed URL converters in a nested namespaced path.

When using include() without namespaces of some urlpatterns that
have an include() with namespace, the converters of the parent
include() weren't being used to convert the arguments of reverse().

AUTHORS

@@ -255,6 +255,7 @@ answer newbie questions, and generally made Django that much better:
     enlight
     Enrico <[email protected]>
     Eric Boersma <[email protected]>
+    Eric Brandwein <[email protected]>
     Eric Floehr <[email protected]>
     Eric Florenzano <[email protected]>
     Eric Holscher <http://ericholscher.com>

django/urls/resolvers.py

@@ -469,6 +469,8 @@ def _populate(self):
                                     )
                                 )
                         for namespace, (prefix, sub_pattern) in url_pattern.namespace_dict.items():
+                            current_converters = url_pattern.pattern.converters
+                            sub_pattern.pattern.converters.update(current_converters)
                             namespaces[namespace] = (p_pattern + prefix, sub_pattern)
                         for app_name, namespace_list in url_pattern.app_dict.items():
                             apps.setdefault(app_name, []).extend(namespace_list)

tests/urlpatterns/path_base64_urls.py

@@ -4,8 +4,16 @@
 
 register_converter(converters.Base64Converter, 'base64')
 
+subsubpatterns = [
+    path('<base64:last_value>/', views.empty_view, name='subsubpattern-base64'),
+]
+
 subpatterns = [
     path('<base64:value>/', views.empty_view, name='subpattern-base64'),
+    path(
+        '<base64:value>/',
+        include((subsubpatterns, 'second-layer-namespaced-base64'), 'instance-ns-base64')
+    ),
 ]
 
 urlpatterns = [

tests/urlpatterns/tests.py

@@ -70,6 +70,13 @@ def test_converter_reverse(self):
                 url = reverse(url_name, kwargs=kwargs)
                 self.assertEqual(url, expected)
 
+    @override_settings(ROOT_URLCONF='urlpatterns.path_base64_urls')
+    def test_converter_reverse_with_second_layer_instance_namespace(self):
+        kwargs = included_kwargs.copy()
+        kwargs['last_value'] = b'world'
+        url = reverse('instance-ns-base64:subsubpattern-base64', kwargs=kwargs)
+        self.assertEqual(url, '/base64/aGVsbG8=/subpatterns/d29ybGQ=/d29ybGQ=/')
+
     def test_path_inclusion_is_matchable(self):
         match = resolve('/included_urls/extra/something/')
         self.assertEqual(match.url_name, 'inner-extra')