Fix incorrect URL generation for missing optional groups

Exclude None values from kwargs in RegexPattern to ensure
translate_url() handles optional named groups correctly.
Adds tests to verify correct URL translation when optional
parameters are absent or present.

Addresses issues with URL translation when optional arguments are missing.

django/urls/resolvers.py

@@ -153,7 +153,7 @@ class RegexPattern(CheckURLMixin):
             # If there are any named groups, use those as kwargs, ignoring
             # non-named groups. Otherwise, pass all non-named arguments as
             # positional arguments.
-            kwargs = match.groupdict()
+            kwargs = {k: v for k, v in match.groupdict().items() if v is not None}
             args = () if kwargs else match.groups()
             return path[match.end():], args, kwargs
         return None

tests/i18n/patterns/tests.py

@@ -157,6 +157,16 @@ class URLTranslationTests(URLTestCaseBase):
             self.assertEqual(translate_url('/en/account/register/', 'nl'), '/nl/profiel/registreren/')
             # path() URL pattern
             self.assertEqual(translate_url('/en/account/register-as-path/', 'nl'), '/nl/profiel/registreren-als-pad/')
+            # URL with optional parameter missing
+            self.assertEqual(
+                translate_url('/en/with-arguments/regular-argument/', 'nl'),
+                '/nl/with-arguments/regular-argument/',
+            )
+            # URL with optional parameter present
+            self.assertEqual(
+                translate_url('/en/with-arguments/regular-argument/optional.html', 'nl'),
+                '/nl/with-arguments/regular-argument/optional.html',
+            )
             self.assertEqual(translation.get_language(), 'en')
 
         with translation.override('nl'):

tests/i18n/patterns/urls/default.py

@@ -15,6 +15,11 @@ urlpatterns = [
 urlpatterns += i18n_patterns(
     path('prefixed/', view, name='prefixed'),
     path('prefixed.xml', view, name='prefixed_xml'),
+    re_path(
+        _(r'^with-arguments/(?P<argument>[\w-]+)/(?:(?P<optional>[\w-]+)\.html)?$'),
+        view,
+        name='with-arguments',
+    ),
     re_path(_(r'^users/$'), view, name='users'),
     re_path(_(r'^account/'), include('i18n.patterns.urls.namespace', namespace='account')),
 )

tests/urlpatterns/path_urls.py

@@ -11,6 +11,7 @@ urlpatterns = [
     path('users/<id>/', views.empty_view, name='user-with-id'),
     path('included_urls/', include('urlpatterns.included_urls')),
     re_path(r'^regex/(?P<pk>[0-9]+)/$', views.empty_view, name='regex'),
+    re_path(r'^regex_optional/(?P<arg1>\d+)/(?:(?P<arg2>\d+)/)?$', views.empty_view, name='regex_optional'),
     path('', include('urlpatterns.more_urls')),
     path('<lang>/<path:url>/', views.empty_view, name='lang-and-path'),
 ]

tests/urlpatterns/tests.py

@@ -54,6 +54,21 @@ class SimplifiedURLTests(SimpleTestCase):
         self.assertEqual(match.kwargs, {'pk': '1'})
         self.assertEqual(match.route, '^regex/(?P<pk>[0-9]+)/$')
 
+    def test_re_path_with_optional_parameter(self):
+        # Test with both optional parameter present and missing
+        for url, expected_kwargs in (
+            ('/regex_optional/1/2/', {'arg1': '1', 'arg2': '2'}),
+            ('/regex_optional/1/', {'arg1': '1'}),
+        ):
+            with self.subTest(url=url):
+                match = resolve(url)
+                self.assertEqual(match.url_name, 'regex_optional')
+                self.assertEqual(match.kwargs, expected_kwargs)
+                self.assertEqual(
+                    match.route,
+                    r'^regex_optional/(?P<arg1>\d+)/(?:(?P<arg2>\d+)/)?$',
+                )
+
     def test_path_lookup_with_inclusion(self):
         match = resolve('/included_urls/extra/something/')
         self.assertEqual(match.url_name, 'inner-extra')