fix: overrides to attribute behavior for resource elems. (#1572)

* fix: overrides to attribute behavior for resource elems.

* addresses comments.

* fixes error.

* fixes test name.

* fixes test.

Author: marcosuma

mongodbatlas/resource_mongodbatlas_cluster.go

@@ -88,10 +88,11 @@ func resourceMongoDBAtlasCluster() *schema.Resource {
 				Description: "Flag that indicates whether to retain backup snapshots for the deleted dedicated cluster",
 			},
 			"bi_connector_config": {
-				Type:     schema.TypeList,
-				Optional: true,
-				Computed: true,
-				MaxItems: 1,
+				Type:       schema.TypeList,
+				Optional:   true,
+				ConfigMode: schema.SchemaConfigModeAttr,
+				Computed:   true,
+				MaxItems:   1,
 				Elem: &schema.Resource{
 					Schema: map[string]*schema.Schema{
 						"enabled": {
@@ -1606,10 +1607,11 @@ func isEqualProviderAutoScalingMaxInstanceSize(k, old, newStr string, d *schema.
 
 func clusterAdvancedConfigurationSchema() *schema.Schema {
 	return &schema.Schema{
-		Type:     schema.TypeList,
-		Optional: true,
-		Computed: true,
-		MaxItems: 1,
+		Type:       schema.TypeList,
+		Optional:   true,
+		Computed:   true,
+		ConfigMode: schema.SchemaConfigModeAttr,
+		MaxItems:   1,
 		Elem: &schema.Resource{
 			Schema: map[string]*schema.Schema{
 				"default_read_concern": {

mongodbatlas/resource_mongodbatlas_cluster_test.go

@@ -10,7 +10,9 @@ import (
 
 	"github.com/hashicorp/terraform-plugin-testing/helper/acctest"
 	"github.com/hashicorp/terraform-plugin-testing/helper/resource"
+	"github.com/hashicorp/terraform-plugin-testing/plancheck"
 	"github.com/hashicorp/terraform-plugin-testing/terraform"
+	"github.com/mongodb/terraform-provider-mongodbatlas/mongodbatlas/testutils"
 	"github.com/mwielbut/pointy"
 	matlas "go.mongodb.org/atlas/mongodbatlas"
 )
@@ -1410,6 +1412,49 @@ func TestAccClusterRSCluster_basicAWS_PausedToUnpaused(t *testing.T) {
 	})
 }
 
+func TestAccClusterRSCluster_withDefaultBiConnectorAndAdvancedConfiguration_maintainsBackwardCompatibility(t *testing.T) {
+	var (
+		cluster      matlas.Cluster
+		resourceName = "mongodbatlas_cluster.test"
+		orgID        = os.Getenv("MONGODB_ATLAS_ORG_ID")
+		projectName  = acctest.RandomWithPrefix("test-acc")
+		name         = fmt.Sprintf("test-acc-%s", acctest.RandString(10))
+		config       = testAccMongoDBAtlasClusterConfigAWS(orgID, projectName, name, true, true)
+	)
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheckBasic(t) },
+		CheckDestroy: testAccCheckMongoDBAtlasClusterDestroy,
+		Steps: []resource.TestStep{
+			{
+				ExternalProviders: map[string]resource.ExternalProvider{
+					"mongodbatlas": {
+						VersionConstraint: "1.11.0",
+						Source:            "mongodb/mongodbatlas",
+					},
+				},
+				Config: config,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckMongoDBAtlasClusterExists(resourceName, &cluster),
+					testAccCheckMongoDBAtlasClusterAttributes(&cluster, name),
+					resource.TestCheckResourceAttrSet(resourceName, "project_id"),
+					resource.TestCheckResourceAttr(resourceName, "name", name),
+				),
+			},
+			{
+				ProtoV6ProviderFactories: testAccProviderV6Factories,
+				Config:                   config,
+				ConfigPlanChecks: resource.ConfigPlanChecks{
+					PostApplyPreRefresh: []plancheck.PlanCheck{
+						testutils.DebugPlan(),
+					},
+				},
+				PlanOnly: true,
+			},
+		},
+	})
+}
+
 func testAccCheckMongoDBAtlasClusterImportStateIDFunc(resourceName string) resource.ImportStateIdFunc {
 	return func(s *terraform.State) (string, error) {
 		rs, ok := s.RootModule().Resources[resourceName]