Bugfix: Webserver returns 500 for POST requests to api/dag/*/dagrun from anonymous user

airflow/auth/managers/base_auth_manager.py

@@ -99,13 +99,15 @@ def get_user_display_name(self) -> str:
     def get_user(self) -> BaseUser | None:
         """Return the user associated to the user in session."""
 
-    def get_user_id(self) -> str:
+    def get_user_id(self) -> str | None:
         """Return the user ID associated to the user in session."""
         user = self.get_user()
         if not user:
             self.log.error("Calling 'get_user_id()' but the user is not signed in.")
             raise AirflowException("The user must be signed in.")
-        return str(user.get_id())
+        if user_id := user.get_id():
+            return str(user_id)
+        return None
 
     def init(self) -> None:
         """

tests/api_connexion/endpoints/test_dag_run_endpoint.py

@@ -1861,3 +1861,22 @@ def test_should_respond_404(self):
             environ_overrides={"REMOTE_USER": "test"},
         )
         assert response.status_code == 404
+
+    @conf_vars(
+        {
+            ("api", "auth_backends"): "airflow.api.auth.backend.default",
+        }
+    )
+    def test_should_respond_200_with_anonymous_user(self, dag_maker, session):
+        from airflow.www import app as application
+
+        app = application.create_app(config={"AUTH_ROLE_PUBLIC": "Admin"}, testing=True)
+        dag_runs = self._create_test_dag_run(DagRunState.SUCCESS)
+        session.add_all(dag_runs)
+        session.commit()
+        created_dr = dag_runs[0]
+        response = app.test_client().patch(
+            f"api/v1/dags/{created_dr.dag_id}/dagRuns/TEST_DAG_RUN_ID_1/setNote",
+            json={"note": "I am setting a note with anonymous user"},
+        )
+        assert response.status_code == 200