Fix tabs for clusterable snippets

wagtail_localize/tests/test_edit_translation.py

@@ -283,7 +283,7 @@ def test_edit_snippet_translation(self):
         self.assertIsNone(props['object']['lastPublishedDate'])
         self.assertIsNone(props['object']['liveUrl'])
         self.assertEqual(props['breadcrumb'], [])
-        self.assertEqual(props['tabs'], [{'label': '', 'slug': ''}])
+        self.assertEqual(props['tabs'], [{'label': 'Content', 'slug': 'content'}])
 
         self.assertEqual(props['sourceLocale'], {'code': 'en', 'displayName': 'English'})
         self.assertEqual(props['locale'], {'code': 'fr', 'displayName': 'French'})

wagtail_localize/views/edit_translation.py

@@ -20,7 +20,7 @@
 from rest_framework.decorators import api_view
 from rest_framework.response import Response
 from wagtail.admin import messages
-from wagtail.admin.edit_handlers import TabbedInterface
+from wagtail.admin.edit_handlers import TabbedInterface, ObjectList
 from wagtail.admin.navigation import get_explorable_root_page
 from wagtail.admin.templatetags.wagtailadmin_tags import avatar_url
 from wagtail.admin.views.pages.utils import get_valid_next_url_from_request
@@ -105,16 +105,23 @@ def edit_handler(self):
 
     @cached_property
     def tabs(self):
-        if isinstance(self.edit_handler, TabbedInterface):
-            tabs = []
+        tabs = []
 
+        if isinstance(self.edit_handler, TabbedInterface):
             for tab in self.edit_handler.children:
-                tabs.append(tab.heading)
-
-            return tabs
-
-        else:
-            return [_("Content")]
+                # On Pages, the TabbedInterface children are instances of ObjectList
+                # which contain the fields
+                # On Snippets, the fields can be added directly into the TabbedInterface
+                # In this case, we do not want to add any tabs and instead just fall back
+                # to the default "Content" tab added below.
+                if isinstance(tab, ObjectList):
+                    tabs.append(tab.heading)
+
+        # Add a default "Content" tab if this object doesn't have any tabs
+        if not tabs:
+            tabs = [_("Content")]
+
+        return tabs
 
     @property
     def tabs_with_slugs(self):