Set explicit default namespace for addon registration (#338)

- Set default Status.Namespace to "open-cluster-management-agent-addon"
- Clarify namespace priority order with explicit default value
- Add test case for default namespace behavior
- Improve test error messages to show actual vs expected values

This ensures a consistent default namespace even when InstallNamespace
is deprecated and agentInstallNamespace is empty.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Signed-off-by: zhujian <[email protected]>
Co-authored-by: Claude <[email protected]>

Author: zhujian7

pkg/addonmanager/controllers/registration/controller.go

@@ -185,21 +185,28 @@ func (c *addonRegistrationController) sync(ctx context.Context, syncCtx factory.
 	}
 	managedClusterAddonCopy.Status.Registrations = configs
 
-	var agentInstallNamespace string
+	// explicitly set the default namespace value, since the mca.spec.installNamespace is deprceated and
+	//  the addonDeploymentConfig.spec.agentInstallNamespace could be empty
+	managedClusterAddonCopy.Status.Namespace = "open-cluster-management-agent-addon"
+
+	// Set the default namespace to registrationOption.Namespace
+	if len(registrationOption.Namespace) > 0 {
+		managedClusterAddonCopy.Status.Namespace = registrationOption.Namespace
+	}
+
+	if len(managedClusterAddonCopy.Spec.InstallNamespace) > 0 {
+		managedClusterAddonCopy.Status.Namespace = managedClusterAddonCopy.Spec.InstallNamespace
+	}
+
 	if registrationOption.AgentInstallNamespace != nil {
-		agentInstallNamespace, err = registrationOption.AgentInstallNamespace(managedClusterAddonCopy)
+		ns, err := registrationOption.AgentInstallNamespace(managedClusterAddonCopy)
 		if err != nil {
 			return err
 		}
-	}
-
-	// Set the default namespace to registrationOption.Namespace
-	managedClusterAddonCopy.Status.Namespace = registrationOption.Namespace
-	// Override if agentInstallNamespace or InstallNamespace is specified
-	if len(agentInstallNamespace) > 0 {
-		managedClusterAddonCopy.Status.Namespace = agentInstallNamespace
-	} else if len(managedClusterAddonCopy.Spec.InstallNamespace) > 0 {
-		managedClusterAddonCopy.Status.Namespace = managedClusterAddonCopy.Spec.InstallNamespace
+		// Override if agentInstallNamespace or InstallNamespace is specified
+		if len(ns) > 0 {
+			managedClusterAddonCopy.Status.Namespace = ns
+		}
 	}
 
 	meta.SetStatusCondition(&managedClusterAddonCopy.Status.Conditions, metav1.Condition{

pkg/addonmanager/controllers/registration/controller_test.go

@@ -173,7 +173,7 @@ func TestReconcile(t *testing.T) {
 					t.Errorf("Registration config is not updated")
 				}
 				if addOn.Status.Namespace != "default2" {
-					t.Errorf("Namespace in status is not correct")
+					t.Errorf("Namespace %s in status is not correct default2", addOn.Status.Namespace)
 				}
 			},
 			testaddon: &testAgent{name: "test", namespace: "default", registrations: []addonapiv1alpha1.RegistrationConfig{
@@ -207,7 +207,7 @@ func TestReconcile(t *testing.T) {
 					t.Errorf("Registration config is not updated")
 				}
 				if addOn.Status.Namespace != "default3" {
-					t.Errorf("Namespace in status is not correct")
+					t.Errorf("Namespace %s in status is not correct default3", addOn.Status.Namespace)
 				}
 			},
 			testaddon: &testAgent{name: "test", namespace: "default",
@@ -217,6 +217,39 @@ func TestReconcile(t *testing.T) {
 				},
 			},
 		},
+		{
+			name:    "default namespace when no namespace is specified",
+			cluster: []runtime.Object{addontesting.NewManagedCluster("cluster1")},
+			addon: []runtime.Object{
+				func() *addonapiv1alpha1.ManagedClusterAddOn {
+					addon := addontesting.NewAddon("test", "cluster1", metav1.OwnerReference{
+						Kind: "ClusterManagementAddOn",
+						Name: "test",
+					})
+					return addon
+				}(),
+			},
+			validateAddonActions: func(t *testing.T, actions []clienttesting.Action) {
+				addontesting.AssertActions(t, actions, "patch")
+				actual := actions[0].(clienttesting.PatchActionImpl).Patch
+				addOn := &addonapiv1alpha1.ManagedClusterAddOn{}
+				err := json.Unmarshal(actual, addOn)
+				if err != nil {
+					t.Fatal(err)
+				}
+				if addOn.Status.Registrations[0].SignerName != "test" {
+					t.Errorf("Registration config is not updated")
+				}
+				if addOn.Status.Namespace != "open-cluster-management-agent-addon" {
+					t.Errorf("Namespace %s in status is not correct, expected open-cluster-management-agent-addon", addOn.Status.Namespace)
+				}
+			},
+			testaddon: &testAgent{name: "test", namespace: "", registrations: []addonapiv1alpha1.RegistrationConfig{
+				{
+					SignerName: "test",
+				},
+			}},
+		},
 	}
 
 	for _, c := range cases {