Prevent namespace update in application resource (#4845)

# Description

This is the change to prevent namespace update in application resource.
Otherwise, Container resource will be deployed to the different
namespace while having the old pod.

## Issue reference

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We strive to have all PR being opened based on an issue, where the
problem or feature have been discussed prior to implementation.
-->

#3740 

## Checklist

Please make sure you've completed the relevant tasks for this PR, out of
the following list:

* [x] Code compiles correctly
* [x] Adds necessary unit tests for change
* [ ] Adds necessary E2E tests for change
* [x] Unit tests passing
* [ ] Extended the documentation / Created issue for it

Co-authored-by: Aaron Crawfis <[email protected]>

pkg/corerp/frontend/controller/applications/createorupdateapplication.go

@@ -116,6 +116,13 @@ func (a *CreateOrUpdateApplication) populateKubernetesNamespace(ctx context.Cont
 		return rest.NewBadRequestResponse(fmt.Sprintf("'%s' is the invalid namespace. This must be at most 63 alphanumeric characters or '-'. Please specify a valid namespace using 'kubernetesNamespace' extension in '$.properties.extensions[*]'.", kubeNamespace)), nil
 	}
 
+	if old != nil {
+		c := old.Properties.Status.Compute
+		if c != nil && c.Kind == rp.KubernetesComputeKind && c.KubernetesCompute.Namespace != kubeNamespace {
+			return rest.NewBadRequestResponse(fmt.Sprintf("Updating an application's Kubernetes namespace from '%s' to '%s' requires the application to be deleted and redeployed. Please delete your application and try again.", c.KubernetesCompute.Namespace, kubeNamespace)), nil
+		}
+	}
+
 	// Populate kubernetes namespace to internal metadata property for query indexing.
 	newResource.Properties.Status.Compute = &rp.EnvironmentCompute{
 		Kind:              rp.KubernetesComputeKind,

pkg/corerp/frontend/controller/applications/createorupdateapplication_test.go

@@ -454,6 +454,22 @@ func TestPopulateKubernetesNamespace_valid_namespace(t *testing.T) {
 	appCtrl := ctl.(*CreateOrUpdateApplication)
 
 	t.Run("override namespace", func(t *testing.T) {
+		old := &datamodel.Application{
+			Properties: datamodel.ApplicationProperties{
+				BasicResourceProperties: rp.BasicResourceProperties{
+					Environment: testEnvID,
+					Status: rp.ResourceStatus{
+						Compute: &rp.EnvironmentCompute{
+							Kind: rp.KubernetesComputeKind,
+							KubernetesCompute: rp.KubernetesComputeProperties{
+								Namespace: "app-ns",
+							},
+						},
+					},
+				},
+			},
+		}
+
 		tCtx.MockSC.
 			EXPECT().
 			Query(gomock.Any(), gomock.Any()).
@@ -482,7 +498,7 @@ func TestPopulateKubernetesNamespace_valid_namespace(t *testing.T) {
 		armctx := &v1.ARMRequestContext{ResourceID: id}
 		ctx := v1.WithARMRequestContext(tCtx.Ctx, armctx)
 
-		resp, err := appCtrl.populateKubernetesNamespace(ctx, nil, newResource)
+		resp, err := appCtrl.populateKubernetesNamespace(ctx, old, newResource)
 		require.NoError(t, err)
 		require.Nil(t, resp)
 
@@ -667,4 +683,55 @@ func TestPopulateKubernetesNamespace_invalid_property(t *testing.T) {
 		res := resp.(*rest.ConflictResponse)
 		require.Equal(t, res.Body.Error.Message, "Application /subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/radius-test-rg/providers/applications.core/applications/app0 with the same namespace (testns) already exists")
 	})
+
+	t.Run("update application with the different namespace", func(t *testing.T) {
+		old := &datamodel.Application{
+			Properties: datamodel.ApplicationProperties{
+				BasicResourceProperties: rp.BasicResourceProperties{
+					Environment: testEnvID,
+					Status: rp.ResourceStatus{
+						Compute: &rp.EnvironmentCompute{
+							Kind: rp.KubernetesComputeKind,
+							KubernetesCompute: rp.KubernetesComputeProperties{
+								Namespace: "default-app0",
+							},
+						},
+					},
+				},
+			},
+		}
+
+		newResource := &datamodel.Application{
+			BaseResource: v1.BaseResource{
+				TrackedResource: v1.TrackedResource{
+					ID: testAppID,
+				},
+			},
+			Properties: datamodel.ApplicationProperties{
+				BasicResourceProperties: rp.BasicResourceProperties{
+					Environment: testEnvID,
+				},
+				Extensions: []datamodel.Extension{
+					{
+						Kind:                datamodel.KubernetesNamespaceExtension,
+						KubernetesNamespace: &datamodel.KubeNamespaceExtension{Namespace: "differentname"},
+					},
+				},
+			},
+		}
+
+		tCtx.MockSC.EXPECT().
+			Query(gomock.Any(), gomock.Any()).
+			Return(&store.ObjectQueryResult{}, nil).Times(2)
+
+		id, err := resources.ParseResource(testAppID)
+		require.NoError(t, err)
+		armctx := &v1.ARMRequestContext{ResourceID: id}
+		ctx := v1.WithARMRequestContext(tCtx.Ctx, armctx)
+
+		resp, err := appCtrl.populateKubernetesNamespace(ctx, old, newResource)
+		require.NoError(t, err)
+		res := resp.(*rest.BadRequestResponse)
+		require.Equal(t, res.Body.Error.Message, "Updating an application's Kubernetes namespace from 'default-app0' to 'differentname' requires the application to be deleted and redeployed. Please delete your application and try again.")
+	})
 }

test/functional/corerp/cli/cli_test.go

@@ -594,8 +594,8 @@ func Test_CLI_Only_version(t *testing.T) {
 }
 
 func Test_RecipeCommands(t *testing.T) {
-	template := "testdata/corerp-resources-environment.bicep"
-	name := "corerp-resources-environment"
+	template := "testdata/corerp-resources-recipe-env.bicep"
+	name := "corerp-resources-recipe-env"
 
 	requiredSecrets := map[string]map[string]string{}
 
@@ -605,7 +605,7 @@ func Test_RecipeCommands(t *testing.T) {
 			CoreRPResources: &validation.CoreRPResourceSet{
 				Resources: []validation.CoreRPResource{
 					{
-						Name: "corerp-resources-environment-env",
+						Name: "corerp-resources-recipe-env",
 						Type: validation.EnvironmentsResource,
 					},
 				},

test/functional/corerp/cli/testdata/corerp-resources-environment.bicep → test/functional/corerp/cli/testdata/corerp-resources-recipe-env.bicep

@@ -4,13 +4,13 @@ import radius as radius
 param location string = 'global'
 
 resource env 'Applications.Core/environments@2022-03-15-privatepreview' = {
-  name: 'corerp-resources-environment-env'
+  name: 'corerp-resources-recipe-env'
   location: location
   properties: {
     compute: {
       kind: 'kubernetes'
       resourceId: 'self'
-      namespace: 'corerp-resources-environment-env'
+      namespace: 'corerp-resources-recipe-env'
     }
     recipes: {
       recipe1: {