rds/option_group: Fix bad diffs with version and port

.changelog/33511.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+resource/aws_db_option_group: Avoid erroneous differences being reported when an `option` `port` and/or `version` is not set
+```

internal/service/rds/flex.go

@@ -259,11 +259,17 @@ func flattenOptions(apiOptions []*rds.Option, optionConfigurations []*rds.Option
 			"db_security_group_memberships":  schema.NewSet(schema.HashString, dbSecurityGroupMemberships),
 			"option_name":                    aws.StringValue(apiOption.OptionName),
 			"option_settings":                schema.NewSet(schema.HashResource(optionSettingsResource), optionSettings),
-			"port":                           aws.Int64Value(apiOption.Port),
-			"version":                        aws.StringValue(apiOption.OptionVersion),
 			"vpc_security_group_memberships": schema.NewSet(schema.HashString, vpcSecurityGroupMemberships),
 		}
 
+		if apiOption.OptionVersion != nil && configuredOption != nil && configuredOption.OptionVersion != nil {
+			r["version"] = aws.StringValue(apiOption.OptionVersion)
+		}
+
+		if apiOption.Port != nil && configuredOption != nil && configuredOption.Port != nil {
+			r["port"] = aws.Int64Value(apiOption.Port)
+		}
+
 		result = append(result, r)
 	}
 

internal/service/rds/option_group_test.go

@@ -521,6 +521,59 @@ func TestAccRDSOptionGroup_Tags_withOptions(t *testing.T) {
 	})
 }
 
+// https://github.com/hashicorp/terraform-provider-aws/issues/21367
+func TestAccRDSOptionGroup_badDiffs(t *testing.T) {
+	ctx := acctest.Context(t)
+	var optionGroup1 rds.OptionGroup
+	resourceName := "aws_db_option_group.test"
+	rName := sdkacctest.RandomWithPrefix(acctest.ResourcePrefix)
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck:                 func() { acctest.PreCheck(ctx, t) },
+		ErrorCheck:               acctest.ErrorCheck(t, rds.EndpointsID),
+		ProtoV5ProviderFactories: acctest.ProtoV5ProviderFactories,
+		CheckDestroy:             testAccCheckOptionGroupDestroy(ctx),
+		Steps: []resource.TestStep{
+			{
+				Config: testAccOptionGroupConfig_badDiffs1(rName),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckOptionGroupExists(ctx, resourceName, &optionGroup1),
+					resource.TestCheckTypeSetElemNestedAttrs(resourceName, "option.*", map[string]string{
+						"port": "3872",
+					}),
+					resource.TestCheckTypeSetElemNestedAttrs(resourceName, "option.*", map[string]string{
+						"option_name": "SQLT",
+					}),
+					resource.TestCheckTypeSetElemNestedAttrs(resourceName, "option.*", map[string]string{
+						"option_name": "S3_INTEGRATION",
+					}),
+				),
+			},
+			{
+				Config:   testAccOptionGroupConfig_badDiffs1(rName),
+				PlanOnly: true,
+			},
+			{
+				Config: testAccOptionGroupConfig_badDiffs2(rName),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckOptionGroupExists(ctx, resourceName, &optionGroup1),
+					resource.TestCheckTypeSetElemNestedAttrs(resourceName, "option.*", map[string]string{
+						"port": "3873",
+					}),
+					resource.TestCheckTypeSetElemNestedAttrs(resourceName, "option.*", map[string]string{
+						"option_name": "SQLT",
+						"version":     "2018-07-25.v1",
+					}),
+					resource.TestCheckTypeSetElemNestedAttrs(resourceName, "option.*", map[string]string{
+						"option_name": "S3_INTEGRATION",
+						"version":     "1.0",
+					}),
+				),
+			},
+		},
+	})
+}
+
 func testAccCheckOptionGroupOptionSettingsIAMRole(optionGroup *rds.OptionGroup) resource.TestCheckFunc {
 	return func(s *terraform.State) error {
 		if optionGroup == nil {
@@ -1053,3 +1106,123 @@ resource "aws_db_option_group" "test" {
 }
 `, rName, tagKey1, tagValue1, tagKey2, tagValue2)
 }
+
+func testAccOptionGroupConfig_badDiffs1(rName string) string {
+	return fmt.Sprintf(`
+resource "aws_security_group" "test" {
+  name = %[1]q
+}
+
+data "aws_rds_engine_version" "default" {
+  engine = "oracle-ee"
+}
+
+resource "aws_db_option_group" "test" {
+  name                     = %[1]q
+  option_group_description = "Option Group for Numagove"
+  engine_name              = data.aws_rds_engine_version.default.engine
+  major_engine_version     = regex("^\\d+", data.aws_rds_engine_version.default.version)
+
+  option {
+    option_name = "S3_INTEGRATION"
+  }
+
+  option {
+    option_name = "SQLT"
+    option_settings {
+      name  = "LICENSE_PACK"
+      value = "T"
+    }
+  }
+
+  option {
+    option_name                    = "OEM_AGENT"
+    version                        = "13.5.0.0.v1"
+    port                           = 3872
+    vpc_security_group_memberships = [aws_security_group.test.id]
+
+    option_settings {
+      name  = "AGENT_REGISTRATION_PASSWORD"
+      value = "TESTPASSWORDBGY"
+    }
+    option_settings {
+      name  = "MINIMUM_TLS_VERSION"
+      value = "TLSv1.2"
+    }
+    option_settings {
+      name  = "TLS_CIPHER_SUITE"
+      value = "TLS_RSA_WITH_AES_128_CBC_SHA"
+    }
+    option_settings {
+      name  = "OMS_HOST"
+      value = "BGY-TEST"
+    }
+    option_settings {
+      name  = "OMS_PORT"
+      value = "1159"
+    }
+  }
+}
+`, rName)
+}
+
+func testAccOptionGroupConfig_badDiffs2(rName string) string {
+	return fmt.Sprintf(`
+resource "aws_security_group" "test" {
+  name = %[1]q
+}
+
+data "aws_rds_engine_version" "default" {
+  engine = "oracle-ee"
+}
+
+resource "aws_db_option_group" "test" {
+  name                     = %[1]q
+  option_group_description = "Option Group for Numagove"
+  engine_name              = data.aws_rds_engine_version.default.engine
+  major_engine_version     = regex("^\\d+", data.aws_rds_engine_version.default.version)
+
+  option {
+    option_name = "S3_INTEGRATION"
+    version     = "1.0"
+  }
+
+  option {
+    option_name = "SQLT"
+    option_settings {
+      name  = "LICENSE_PACK"
+      value = "T"
+    }
+    version = "2018-07-25.v1"
+  }
+
+  option {
+    option_name                    = "OEM_AGENT"
+    version                        = "13.5.0.0.v1"
+    port                           = 3873
+    vpc_security_group_memberships = [aws_security_group.test.id]
+
+    option_settings {
+      name  = "AGENT_REGISTRATION_PASSWORD"
+      value = "TESTPASSWORDBGY"
+    }
+    option_settings {
+      name  = "MINIMUM_TLS_VERSION"
+      value = "TLSv1.2"
+    }
+    option_settings {
+      name  = "TLS_CIPHER_SUITE"
+      value = "TLS_RSA_WITH_AES_128_CBC_SHA"
+    }
+    option_settings {
+      name  = "OMS_HOST"
+      value = "BGY-TEST"
+    }
+    option_settings {
+      name  = "OMS_PORT"
+      value = "1159"
+    }
+  }
+}
+`, rName)
+}

website/docs/r/db_option_group.html.markdown

@@ -62,35 +62,35 @@ More information about this can be found [here](https://docs.aws.amazon.com/Amaz
 
 This resource supports the following arguments:
 
-* `name` - (Optional, Forces new resource) The name of the option group. If omitted, Terraform will assign a random, unique name. Must be lowercase, to match as it is stored in AWS.
+* `name` - (Optional, Forces new resource) Name of the option group. If omitted, Terraform will assign a random, unique name. Must be lowercase, to match as it is stored in AWS.
 * `name_prefix` - (Optional, Forces new resource) Creates a unique name beginning with the specified prefix. Conflicts with `name`. Must be lowercase, to match as it is stored in AWS.
-* `option_group_description` - (Optional) The description of the option group. Defaults to "Managed by Terraform".
+* `option_group_description` - (Optional) Description of the option group. Defaults to "Managed by Terraform".
 * `engine_name` - (Required) Specifies the name of the engine that this option group should be associated with.
 * `major_engine_version` - (Required) Specifies the major version of the engine that this option group should be associated with.
-* `option` - (Optional) A list of Options to apply.
-* `tags` - (Optional) A map of tags to assign to the resource. If configured with a provider [`default_tags` configuration block](https://registry.terraform.io/providers/hashicorp/aws/latest/docs#default_tags-configuration-block) present, tags with matching keys will overwrite those defined at the provider-level.
+* `option` - (Optional) List of options to apply.
+* `tags` - (Optional) Map of tags to assign to the resource. If configured with a provider [`default_tags` configuration block](https://registry.terraform.io/providers/hashicorp/aws/latest/docs#default_tags-configuration-block) present, tags with matching keys will overwrite those defined at the provider-level.
 
-Option blocks support the following:
+`option` blocks support the following:
 
-* `option_name` - (Required) The Name of the Option (e.g., MEMCACHED).
-* `option_settings` - (Optional) A list of option settings to apply.
-* `port` - (Optional) The Port number when connecting to the Option (e.g., 11211).
-* `version` - (Optional) The version of the option (e.g., 13.1.0.0).
-* `db_security_group_memberships` - (Optional) A list of DB Security Groups for which the option is enabled.
-* `vpc_security_group_memberships` - (Optional) A list of VPC Security Groups for which the option is enabled.
+* `option_name` - (Required) Name of the option (e.g., MEMCACHED).
+* `option_settings` - (Optional) List of option settings to apply.
+* `port` - (Optional) Port number when connecting to the option (e.g., 11211). Leaving out or removing `port` from your configuration does not remove or clear a port from the option in AWS. AWS may assign a default port. Not including `port` in your configuration means that the AWS provider will ignore a previously set value, a value set by AWS, and any port changes.
+* `version` - (Optional) Version of the option (e.g., 13.1.0.0). Leaving out or removing `version` from your configuration does not remove or clear a version from the option in AWS. AWS may assign a default version. Not including `version` in your configuration means that the AWS provider will ignore a previously set value, a value set by AWS, and any version changes.
+* `db_security_group_memberships` - (Optional) List of DB Security Groups for which the option is enabled.
+* `vpc_security_group_memberships` - (Optional) List of VPC Security Groups for which the option is enabled.
 
-Option Settings blocks support the following:
+`option_settings` blocks support the following:
 
-* `name` - (Optional) The Name of the setting.
-* `value` - (Optional) The Value of the setting.
+* `name` - (Optional) Name of the setting.
+* `value` - (Optional) Value of the setting.
 
 ## Attribute Reference
 
 This resource exports the following attributes in addition to the arguments above:
 
-* `id` - The db option group name.
-* `arn` - The ARN of the db option group.
-* `tags_all` - A map of tags assigned to the resource, including those inherited from the provider [`default_tags` configuration block](https://registry.terraform.io/providers/hashicorp/aws/latest/docs#default_tags-configuration-block).
+* `id` - DB option group name.
+* `arn` - ARN of the DB option group.
+* `tags_all` - Map of tags assigned to the resource, including those inherited from the provider [`default_tags` configuration block](https://registry.terraform.io/providers/hashicorp/aws/latest/docs#default_tags-configuration-block).
 
 ## Timeouts
 
@@ -100,7 +100,7 @@ This resource exports the following attributes in addition to the arguments abov
 
 ## Import
 
-In Terraform v1.5.0 and later, use an [`import` block](https://developer.hashicorp.com/terraform/language/import) to import DB Option groups using the `name`. For example:
+In Terraform v1.5.0 and later, use an [`import` block](https://developer.hashicorp.com/terraform/language/import) to import DB option groups using the `name`. For example:
 
 ```terraform
 import {
@@ -109,7 +109,7 @@ import {
 }
 ```
 
-Using `terraform import`, import DB Option groups using the `name`. For example:
+Using `terraform import`, import DB option groups using the `name`. For example:
 
 ```console
 % terraform import aws_db_option_group.example mysql-option-group