workflows: correctly reset display/structured data (#46657)

tests/test_workflows.py

@@ -5267,6 +5267,25 @@ def test_edit_carddata_with_data_sourced_object(pub):
     assert data.data['2'] == 'b'
     assert data.data['2_display'] == 'baker'
 
+    # reset data
+    edit.mappings = [
+        Mapping(field_id='2', expression='=None'),
+    ]
+    wf.store()
+
+    formdata = formdef.data_class()()
+    formdata.data = {
+        '0': '1',
+        '1': 'b'
+    }
+    formdata.store()
+    formdata.just_created()
+    formdata.perform_workflow()
+
+    data = carddef.data_class().select()[0]
+    assert data.data['2'] is None
+    assert data.data['2_display'] is None
+
 
 def test_edit_carddata_with_linked_object(pub):
     FormDef.wipe()

wcs/wf/create_formdata.py

@@ -424,7 +424,12 @@ class CreateFormdataWorkflowStatusItem(WorkflowStatusItem):
 
         formdata.data['%s' % field.id] = value
         if value is None:
+            if field.store_display_value:
+                formdata.data['%s_display' % field.id] = None
+            if field.store_structured_value:
+                formdata.data['%s_structured' % field.id] = None
             return
+
         if field.store_display_value:
             display_value = field.store_display_value(
                 formdata.data, field.id)