Add DNS_SCOPE_UNSPECIFIED back and fix diffs

.changelog/13348.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+container: re-added `DNS_SCOPE_UNSPECIFIED` value to the `dns_config.cluster_dns_scope` field in `google_container_cluster` resource and suppressed diffs between `DNS_SCOPE_UNSPECIFIED` in config and empty/null in state
+```

google-beta/services/container/resource_container_cluster.go

@@ -188,6 +188,13 @@ func isBeenEnabled(_ context.Context, old, new, _ interface{}) bool {
 	return false
 }
 
+func suppressDiffForClusterDnsScope(k, o, n string, d *schema.ResourceData) bool {
+	if o == "" && n == "DNS_SCOPE_UNSPECIFIED" {
+		return true
+	}
+	return false
+}
+
 func ResourceContainerCluster() *schema.Resource {
 	return &schema.Resource{
 		UseJSONNumber: true,
@@ -2179,10 +2186,11 @@ func ResourceContainerCluster() *schema.Resource {
 							Optional:     true,
 						},
 						"cluster_dns_scope": {
-							Type:         schema.TypeString,
-							ValidateFunc: validation.StringInSlice([]string{"CLUSTER_SCOPE", "VPC_SCOPE"}, false),
-							Description:  `The scope of access to cluster DNS records.`,
-							Optional:     true,
+							Type:             schema.TypeString,
+							ValidateFunc:     validation.StringInSlice([]string{"DNS_SCOPE_UNSPECIFIED", "CLUSTER_SCOPE", "VPC_SCOPE"}, false),
+							Description:      `The scope of access to cluster DNS records.`,
+							Optional:         true,
+							DiffSuppressFunc: suppressDiffForClusterDnsScope,
 						},
 						"cluster_dns_domain": {
 							Type:        schema.TypeString,

google-beta/services/container/resource_container_cluster_test.go

@@ -6042,7 +6042,21 @@ func TestAccContainerCluster_cloudDns_nil_scope(t *testing.T) {
 		CheckDestroy:             testAccCheckContainerClusterDestroyProducer(t),
 		Steps: []resource.TestStep{
 			{
-				Config: testAccContainerCluster_withAdvancedDNSConfig(clusterName, false, true, true, false, ""),
+				Config: testAccContainerCluster_withDNSConfigWithoutScope(clusterName),
+			},
+			{
+				ResourceName:            "google_container_cluster.primary",
+				ImportState:             true,
+				ImportStateVerify:       true,
+				ImportStateVerifyIgnore: []string{"deletion_protection"},
+			},
+			{
+				Config: testAccContainerCluster_withDNSConfigWithUnspecifiedScope(clusterName),
+				ConfigPlanChecks: resource.ConfigPlanChecks{
+					PreApply: []plancheck.PlanCheck{
+						plancheck.ExpectResourceAction("google_container_cluster.primary", plancheck.ResourceActionNoop),
+					},
+				},
 			},
 			{
 				ResourceName:            "google_container_cluster.primary",
@@ -6054,6 +6068,37 @@ func TestAccContainerCluster_cloudDns_nil_scope(t *testing.T) {
 	})
 }
 
+func testAccContainerCluster_withDNSConfigWithoutScope(clusterName string) string {
+	return fmt.Sprintf(`
+resource "google_container_cluster" "primary" {
+  name               = "%s"
+  location           = "us-central1-a"
+  initial_node_count = 2
+  dns_config {
+    cluster_dns      = "CLOUD_DNS"
+  }
+
+  deletion_protection = false
+}
+`, clusterName)
+}
+
+func testAccContainerCluster_withDNSConfigWithUnspecifiedScope(clusterName string) string {
+	return fmt.Sprintf(`
+resource "google_container_cluster" "primary" {
+  name                = "%s"
+  location            = "us-central1-a"
+  initial_node_count  = 2
+  dns_config {
+    cluster_dns       = "CLOUD_DNS"
+    cluster_dns_scope = "DNS_SCOPE_UNSPECIFIED"
+  }
+
+  deletion_protection = false
+}
+`, clusterName)
+}
+
 func TestAccContainerCluster_autopilot_withAdditiveVPCMutation(t *testing.T) {
 	t.Parallel()
 

website/docs/r/container_cluster.html.markdown

@@ -1427,7 +1427,7 @@ linux_node_config {
 
 * `cluster_dns` - (Optional) Which in-cluster DNS provider should be used. `PROVIDER_UNSPECIFIED` (default) or `PLATFORM_DEFAULT` or `CLOUD_DNS`.
 
-* `cluster_dns_scope` - (Optional) The scope of access to cluster DNS records. `DNS_SCOPE_UNSPECIFIED` (default) or `CLUSTER_SCOPE` or `VPC_SCOPE`.
+* `cluster_dns_scope` - (Optional) The scope of access to cluster DNS records. `DNS_SCOPE_UNSPECIFIED` or `CLUSTER_SCOPE` or `VPC_SCOPE`. If the `cluster_dns` field is set to `CLOUD_DNS`, `DNS_SCOPE_UNSPECIFIED` and empty/null behave like `CLUSTER_SCOPE`.
 
 * `cluster_dns_domain` - (Optional) The suffix used for all cluster service records.