Move snippets ReferenceIndex registration to ModelViewSet

wagtail/admin/viewsets/model.py

@@ -8,6 +8,7 @@ from wagtail.admin.admin_url_finder import (
     register_admin_url_finder,
 )
 from wagtail.admin.views import generic
+from wagtail.models import ReferenceIndex
 from wagtail.permissions import ModelPermissionPolicy
 
 from .base import ViewSet, ViewSetGroup
@@ -183,6 +184,9 @@ class ModelViewSet(ViewSet):
     def register_admin_url_finder(self):
         register_admin_url_finder(self.model, self.url_finder_class)
 
+    def register_reference_index(self):
+        ReferenceIndex.register_model(self.model)
+
     def get_urlpatterns(self):
         return super().get_urlpatterns() + [
             path("", self.index_view, name="index"),
@@ -195,6 +199,7 @@ class ModelViewSet(ViewSet):
     def on_register(self):
         super().on_register()
         self.register_admin_url_finder()
+        self.register_reference_index()
 
 
 class ModelViewSetGroup(ViewSetGroup):

wagtail/snippets/views/snippets.py

@@ -42,7 +42,6 @@ from wagtail.models import (
     Locale,
     LockableMixin,
     PreviewableMixin,
-    ReferenceIndex,
     RevisionMixin,
     WorkflowMixin,
 )
@@ -1544,9 +1543,6 @@ class SnippetViewSet(ModelViewSet):
         snippet_models.append(self.model)
         snippet_models.sort(key=lambda x: x._meta.verbose_name)
 
-    def register_reference_index(self):
-        ReferenceIndex.register_model(self.model)
-
     def on_register(self):
         super().on_register()
         # For convenience, attach viewset to the model class to allow accessing
@@ -1555,7 +1551,6 @@ class SnippetViewSet(ModelViewSet):
         self.register_chooser_viewset()
         self.register_model_check()
         self.register_snippet_model()
-        self.register_reference_index()
 
 
 class SnippetViewSetGroup(ModelViewSetGroup):