misc: avoid unrelated evolution parts when looking for related data (#46678)

tests/test_backoffice_pages.py

@@ -5450,6 +5450,15 @@ def test_inspect_page_with_related_objects(pub):
 
     wf = Workflow(name='External actions')
     st1 = wf.add_status('Create external formdata')
+
+    # add a message to history, to check it doesn't interfer when searching for
+    # linked data.
+    register_comment = RegisterCommenterWorkflowStatusItem()
+    register_comment.id = '_register'
+    register_comment.comment = '<p>test</p>'
+    st1.items.append(register_comment)
+    register_comment.parent = st1
+
     create_formdata = CreateFormdataWorkflowStatusItem()
     create_formdata.label = 'create linked form'
     create_formdata.formdef_slug = external_formdef.url_name

wcs/formdata.py

@@ -1229,13 +1229,14 @@ class FormData(StorableObject):
 
         # search in evolution
         for part in self.iter_evolution_parts():
-            is_linked = isinstance(part, LinkedFormdataEvolutionPart)
+            if not isinstance(part, LinkedFormdataEvolutionPart):
+                continue
             part_identifier = '%s:%s' % (part.formdef.xml_root_node, part.formdef.url_name)
-            if is_linked and object_type:
+            if object_type:
                 # looking for an object of a specific type (workflow action)
                 if part_identifier == object_type:
                     data_ids.append((part_identifier, part.formdata_id))
-            elif is_linked:
+            else:
                 # looking for any object (inspect page)
                 data_ids.append((part_identifier, part.formdata_id))