Fix dag_versions property when created_dag_version is None with bundle_version set

airflow-core/src/airflow/models/dagrun.py

@@ -371,7 +371,7 @@ def dag_versions(self) -> list[DagVersion]:
         """Return the DAG versions associated with the TIs of this DagRun."""
         # when the dag is in a versioned bundle, we keep the dag version fixed
         if self.bundle_version:
-            return [self.created_dag_version]
+            return [self.created_dag_version] if self.created_dag_version is not None else []
         dag_versions = [
             dv
             for dv in dict.fromkeys(list(self._tih_dag_versions) + list(self._ti_dag_versions))

airflow-core/tests/unit/models/test_dagrun.py

@@ -1260,6 +1260,27 @@ def test_dag_run_version_number(self, dag_maker, session):
         # the latest task instance dag_version
         assert dag_run.version_number == dag_v.version_number
 
+    def test_dag_run_dag_versions_with_null_created_dag_version(self, dag_maker, session):
+        """Test that dag_versions returns empty list when created_dag_version is None and bundle_version is populated."""
+        with dag_maker(
+            "test_dag_run_null_created_dag_version",
+            schedule=datetime.timedelta(days=1),
+            start_date=DEFAULT_DATE,
+        ):
+            EmptyOperator(task_id="empty")
+        dag_run = dag_maker.create_dagrun()
+
+        dag_run.bundle_version = "some_bundle_version"
+        dag_run.created_dag_version_id = None
+        dag_run.created_dag_version = None
+        session.merge(dag_run)
+        session.flush()
+
+        # This should return empty list, not [None]
+        assert dag_run.dag_versions == []
+        assert isinstance(dag_run.dag_versions, list)
+        assert len(dag_run.dag_versions) == 0
+
     def test_dagrun_success_deadline(self, dag_maker, session):
         def on_success_callable(context):
             assert context["dag_run"].dag_id == "test_dagrun_success_callback"