[Enhancement] aws_cognito_user_pool: Update name attribute without resource replacement

.changelog/42639.txt

@@ -0,0 +1,3 @@
+```release-note:enhancement
+resource/aws_cognito_user_pool: The name attribute can now be updated in-place, instead of requiring resource replacement
+```

internal/service/cognitoidp/user_pool.go

@@ -395,7 +395,6 @@ func resourceUserPool() *schema.Resource {
 			names.AttrName: {
 				Type:     schema.TypeString,
 				Required: true,
-				ForceNew: true,
 				ValidateFunc: validation.Any(
 					validation.StringLenBetween(1, 128),
 					validation.StringMatch(regexache.MustCompile(`[\w\s+=,.@-]+`),
@@ -1069,6 +1068,7 @@ func resourceUserPoolUpdate(ctx context.Context, d *schema.ResourceData, meta an
 		"email_verification_message",
 		"email_verification_subject",
 		"lambda_config",
+		names.AttrName,
 		"password_policy",
 		"sign_in_policy",
 		"sms_authentication_message",
@@ -1148,6 +1148,10 @@ func resourceUserPoolUpdate(ctx context.Context, d *schema.ResourceData, meta an
 			}
 		}
 
+		if v, ok := d.GetOk(names.AttrName); ok {
+			input.PoolName = aws.String(v.(string))
+		}
+
 		if v, ok := d.GetOk("mfa_configuration"); ok {
 			input.MfaConfiguration = awstypes.UserPoolMfaType(v.(string))
 		}

internal/service/cognitoidp/user_pool_test.go

@@ -2036,6 +2036,38 @@ func TestAccCognitoIDPUserPool_userPoolTier(t *testing.T) {
 	})
 }
 
+func TestAccCognitoIDPUserPool_nameUpdate(t *testing.T) {
+	ctx := acctest.Context(t)
+	var pool1, pool2 awstypes.UserPoolType
+	rName := sdkacctest.RandomWithPrefix(acctest.ResourcePrefix)
+	resourceName := "aws_cognito_user_pool.test"
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck:                 func() { acctest.PreCheck(ctx, t); testAccPreCheckIdentityProvider(ctx, t) },
+		ErrorCheck:               acctest.ErrorCheck(t, names.CognitoIDPServiceID),
+		ProtoV5ProviderFactories: acctest.ProtoV5ProviderFactories,
+		CheckDestroy:             testAccCheckUserPoolDestroy(ctx),
+		Steps: []resource.TestStep{
+			{
+				Config: testAccUserPoolConfig_name(rName + "-test1"),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					testAccCheckUserPoolExists(ctx, resourceName, &pool1),
+					resource.TestCheckResourceAttr(resourceName, names.AttrName, rName+"-test1"),
+				),
+			},
+			{
+				Config: testAccUserPoolConfig_name(rName + "-test2"),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					testAccCheckUserPoolExists(ctx, resourceName, &pool2),
+					resource.TestCheckResourceAttr(resourceName, names.AttrName, rName+"-test2"),
+					// check that the user pool was not recreated
+					testAccCheckUserPoolIdEqual(&pool1, &pool2),
+				),
+			},
+		},
+	})
+}
+
 func testAccCheckUserPoolDestroy(ctx context.Context) resource.TestCheckFunc {
 	return func(s *terraform.State) error {
 		conn := acctest.Provider.Meta().(*conns.AWSClient).CognitoIDPClient(ctx)
@@ -2099,6 +2131,18 @@ func testAccPreCheckIdentityProvider(ctx context.Context, t *testing.T) {
 	acctest.PreCheckCognitoIdentityProvider(ctx, t)
 }
 
+func testAccCheckUserPoolIdEqual(pool1 *awstypes.UserPoolType, pool2 *awstypes.UserPoolType) resource.TestCheckFunc {
+	return func(s *terraform.State) error {
+		if pool1.Id == nil || pool2.Id == nil {
+			return fmt.Errorf("user pool ID is nil")
+		}
+		if aws.ToString(pool1.Id) != aws.ToString(pool2.Id) {
+			return fmt.Errorf("user pool %s should not have been replaced with %s", aws.ToString(pool1.Id), aws.ToString(pool2.Id))
+		}
+		return nil
+	}
+}
+
 func testAccUserPoolSMSConfigurationConfig_base(rName string, externalID string) string {
 	return fmt.Sprintf(`
 data "aws_partition" "current" {}