fix replication_specs behaviour when update cluster (#573)

Author: abner-dou

mongodbatlas/resource_mongodbatlas_cluster.go

@@ -1168,6 +1168,7 @@ func expandReplicationSpecs(d *schema.ResourceData) ([]matlas.ReplicationSpec, e
 
 			replaceRegion := ""
 			originalRegion := ""
+			id := ""
 
 			if okPRName && d.Get("provider_name").(string) == "GCP" && cast.ToString(d.Get("cluster_type")) == "REPLICASET" {
 				if d.HasChange("provider_region_name") {
@@ -1177,13 +1178,25 @@ func expandReplicationSpecs(d *schema.ResourceData) ([]matlas.ReplicationSpec, e
 				}
 			}
 
+			if d.HasChange("replication_specs") {
+				// Get original and new object
+				original, _ := d.GetChange("replication_specs")
+				for _, s := range original.(*schema.Set).List() {
+					oldSpecs := s.(map[string]interface{})
+					if spec["zone_name"].(string) == cast.ToString(oldSpecs["zone_name"]) {
+						id = oldSpecs["id"].(string)
+						break
+					}
+				}
+			}
+
 			regionsConfig, err := expandRegionsConfig(spec["regions_config"].(*schema.Set).List(), originalRegion, replaceRegion)
 			if err != nil {
 				return rSpecs, err
 			}
 
 			rSpec := matlas.ReplicationSpec{
-				ID:            cast.ToString(spec["id"]),
+				ID:            id,
 				NumShards:     pointy.Int64(cast.ToInt64(spec["num_shards"])),
 				ZoneName:      cast.ToString(spec["zone_name"]),
 				RegionsConfig: regionsConfig,

mongodbatlas/resource_mongodbatlas_cluster_test.go

@@ -461,13 +461,39 @@ func TestAccResourceMongoDBAtlasCluster_MultiRegion(t *testing.T) {
 		name         = fmt.Sprintf("test-acc-multi-%s", acctest.RandString(10))
 	)
 
+	createRegionsConfig := `regions_config {
+					region_name     = "US_EAST_1"
+					electable_nodes = 3
+					priority        = 7
+					read_only_nodes = 0
+				}`
+
+	updatedRegionsConfig := `regions_config {
+					region_name     = "US_WEST_2"
+					electable_nodes = 3
+					priority        = 6
+					read_only_nodes = 0
+				}
+				regions_config {
+					region_name     = "US_WEST_1"
+					electable_nodes = 1
+					priority        = 5
+					read_only_nodes = 0
+				}
+				regions_config {
+					region_name     = "US_EAST_1"
+					electable_nodes = 3
+					priority        = 7
+					read_only_nodes = 0
+				}`
+
 	resource.ParallelTest(t, resource.TestCase{
 		PreCheck:          func() { testAccPreCheck(t) },
 		ProviderFactories: testAccProviderFactories,
 		CheckDestroy:      testAccCheckMongoDBAtlasClusterDestroy,
 		Steps: []resource.TestStep{
 			{
-				Config: testAccMongoDBAtlasClusterConfigMultiRegion(projectID, name, "true"),
+				Config: testAccMongoDBAtlasClusterConfigMultiRegion(projectID, name, "true", createRegionsConfig),
 				Check: resource.ComposeTestCheckFunc(
 					testAccCheckMongoDBAtlasClusterExists(resourceName, &cluster),
 					testAccCheckMongoDBAtlasClusterAttributes(&cluster, name),
@@ -479,11 +505,11 @@ func TestAccResourceMongoDBAtlasCluster_MultiRegion(t *testing.T) {
 					resource.TestCheckResourceAttr(resourceName, "disk_size_gb", "100"),
 					resource.TestCheckResourceAttr(resourceName, "cluster_type", "REPLICASET"),
 					resource.TestCheckResourceAttr(resourceName, "replication_specs.#", "1"),
-					resource.TestCheckResourceAttr(resourceName, "replication_specs.0.regions_config.#", "3"),
+					resource.TestCheckResourceAttr(resourceName, "replication_specs.0.regions_config.#", "1"),
 				),
 			},
 			{
-				Config: testAccMongoDBAtlasClusterConfigMultiRegion(projectID, name, "false"),
+				Config: testAccMongoDBAtlasClusterConfigMultiRegion(projectID, name, "false", updatedRegionsConfig),
 				Check: resource.ComposeTestCheckFunc(
 					testAccCheckMongoDBAtlasClusterExists(resourceName, &cluster),
 					testAccCheckMongoDBAtlasClusterAttributes(&cluster, name),
@@ -1458,7 +1484,7 @@ func testAccMongoDBAtlasClusterConfigGCPWithBiConnector(projectID, name, backupE
 	`, projectID, name, backupEnabled, biConnectorEnabled)
 }
 
-func testAccMongoDBAtlasClusterConfigMultiRegion(projectID, name, backupEnabled string) string {
+func testAccMongoDBAtlasClusterConfigMultiRegion(projectID, name, backupEnabled, regionsConfig string) string {
 	return fmt.Sprintf(`
 		resource "mongodbatlas_cluster" "multi_region" {
 			project_id              = "%s"
@@ -1475,27 +1501,10 @@ func testAccMongoDBAtlasClusterConfigMultiRegion(projectID, name, backupEnabled
 			replication_specs {
 				num_shards = 1
 
-				regions_config {
-					region_name     = "US_WEST_2"
-					electable_nodes = 3
-					priority        = 7
-					read_only_nodes = 0
-				}
-				regions_config {
-					region_name     = "EU_CENTRAL_1"
-					electable_nodes = 2
-					priority        = 6
-					read_only_nodes = 0
-				}
-				regions_config {
-					region_name     = "US_WEST_1"
-					electable_nodes = 2
-					priority        = 5
-					read_only_nodes = 2
-				}
+				%s
 			}
 		}
-	`, projectID, name, backupEnabled)
+	`, projectID, name, backupEnabled, regionsConfig)
 }
 
 func testAccMongoDBAtlasClusterConfigGlobal(projectID, name, backupEnabled string) string {