Include descendants when applying bulk actions to page search results

wagtail/admin/views/pages/bulk_actions/page_bulk_action.py

@@ -16,14 +16,22 @@ class PageBulkAction(BulkAction):
     def get_all_objects_in_listing_query(self, parent_id):
         listing_objects = self.model.objects.all()
 
-        if parent_id is not None:
-            listing_objects = listing_objects.get(id=parent_id).get_children()
-
-        listing_objects = listing_objects.values_list("pk", flat=True)
-
+        q = None
         if "q" in self.request.GET:
             q = self.request.GET.get("q", "")
 
+        if parent_id is not None:
+            listing_objects = listing_objects.get(id=parent_id)
+            # If we're searching, include the descendants as well.
+            # Otherwise, just include the direct children.
+            if q:
+                listing_objects = listing_objects.get_descendants()
+            else:
+                listing_objects = listing_objects.get_children()
+
+        listing_objects = listing_objects.values_list("pk", flat=True)
+
+        if q:
             listing_objects = page_filter_search(q, listing_objects)[0].results()
 
         return listing_objects