misc: add missing errors import before raising themes 404 errors (#37373)

tests/test_admin_pages.py

@@ -5253,6 +5253,11 @@ def test_settings_theme_download_upload(pub):
     assert os.path.exists(os.path.join(pub.app_dir, 'themes/alto/foobar.txt'))
 
     assert app.get('/themes/alto/foobar.txt').body == 'XXX'
+    assert 'Directory listing denied' in app.get('/themes/alto/', status=200).body
+
+    assert app.get('/themes/alto/plop', status=404)
+    assert app.get('/themes/alto/../', status=404)
+    assert app.get('/themes/xxx/../', status=404)
 
 def test_bounces(pub):
     create_superuser(pub)

wcs/qommon/template.py

@@ -65,6 +65,7 @@ def get_theme_directory(theme_id):
 
 class ThemesDirectory(Directory):
     def _q_lookup(self, name):
+        from . import errors
         if name in ('.', '..'):
             raise errors.TraversalError()