Merge pull request #535 from plone/fix-create-relation-none

In relation.create, handle existing value of None
plone · Apr 30, 2024 · 7dc8997 · 7dc8997
2 parents f2ac29a + 5677a0c
commit 7dc8997
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diff --git a/news/535.bugfix b/news/535.bugfix
@@ -0,0 +1 @@
+In relation.create: Fix edge case where existing RelationList value is None. @davisagli
diff --git a/src/plone/api/relation.py b/src/plone/api/relation.py
@@ -217,7 +217,7 @@ def create(source=None, target=None, relationship=None):
             target.absolute_url(),
         )
         if not has_relation:
-            existing_relations = getattr(source, from_attribute, [])
+            existing_relations = getattr(source, from_attribute, None) or []
             existing_relations.append(RelationValue(to_id))
             setattr(source, from_attribute, existing_relations)
             modified(source)