r/aws_route53_zone: prevent re-creation with uppercase name

This change handles normalizing the `name` argument such that the value returned from the Route53 API matches what is stored in state. Previously, if the `name` argument included an uppercase letter a persistent difference would be present, causing the resource to be re-created.

```console
% make testacc PKG=route53 TESTS=TestAccRoute53Zone_
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go1.21.8 test ./internal/service/route53/... -v -count 1 -parallel 20 -run='TestAccRoute53Zone_'  -timeout 360m

--- PASS: TestAccRoute53Zone_disappears (57.95s)
--- PASS: TestAccRoute53Zone_delegationSetID (65.40s)
--- PASS: TestAccRoute53Zone_basic (66.34s)
--- PASS: TestAccRoute53Zone_VPC_single (70.98s)
--- PASS: TestAccRoute53Zone_comment (71.97s)
--- PASS: TestAccRoute53Zone_multiple (74.73s)
--- PASS: TestAccRoute53Zone_tags (76.63s)
--- PASS: TestAccRoute53Zone_VPC_multiple (143.04s)
--- PASS: TestAccRoute53Zone_VPC_single_forceDestroy (190.01s)
--- PASS: TestAccRoute53Zone_VPC_updates (212.37s)
--- PASS: TestAccRoute53Zone_forceDestroy (258.91s)
--- PASS: TestAccRoute53Zone_ForceDestroy_trailingPeriod (274.02s)
PASS
ok      github.com/hashicorp/terraform-provider-aws/internal/service/route53    279.439
```

```console
% make testacc PKG=route53 TESTS=TestAccRoute53ZoneDataSource_
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go1.21.8 test ./internal/service/route53/... -v -count 1 -parallel 20 -run='TestAccRoute53ZoneDataSource_'  -timeout 360m

--- PASS: TestAccRoute53ZoneDataSource_id (45.26s)
--- PASS: TestAccRoute53ZoneDataSource_name (48.35s)
--- PASS: TestAccRoute53ZoneDataSource_tags (65.21s)
--- PASS: TestAccRoute53ZoneDataSource_vpc (83.68s)
--- PASS: TestAccRoute53ZoneDataSource_serviceDiscovery (102.34s)
PASS
ok      github.com/hashicorp/terraform-provider-aws/internal/service/route53    107.890s
```

.changelog/36563.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+resource/aws_route53_zone: Prevent re-creation when `name` casing changes
+```

internal/service/route53/zone.go

@@ -82,7 +82,7 @@ func ResourceZone() *schema.Resource {
 				Type:         schema.TypeString,
 				Required:     true,
 				ForceNew:     true,
-				StateFunc:    TrimTrailingPeriod,
+				StateFunc:    NormalizeZoneName,
 				ValidateFunc: validation.StringLenBetween(1, 1024),
 			},
 			"name_servers": {
@@ -209,7 +209,7 @@ func resourceZoneRead(ctx context.Context, d *schema.ResourceData, meta interfac
 	d.Set("delegation_set_id", "")
 	// To be consistent with other AWS services (e.g. ACM) that do not accept a trailing period,
 	// we remove the suffix from the Hosted Zone Name returned from the API
-	d.Set("name", TrimTrailingPeriod(aws.StringValue(output.HostedZone.Name)))
+	d.Set("name", NormalizeZoneName(aws.StringValue(output.HostedZone.Name)))
 	d.Set("zone_id", CleanZoneID(aws.StringValue(output.HostedZone.Id)))
 
 	var nameServers []string
@@ -549,11 +549,14 @@ func CleanZoneID(ID string) string {
 	return strings.TrimPrefix(ID, "/hostedzone/")
 }
 
-// TrimTrailingPeriod is used to remove the trailing period
-// of "name" or "domain name" attributes often returned from
-// the Route53 API or provided as user input.
+// NormalizeZoneName is used to remove the trailing period
+// and apply consistent casing to "name" or "domain name"
+// attributes returned from the Route53 API or provided as
+// user input.
+//
 // The single dot (".") domain name is returned as-is.
-func TrimTrailingPeriod(v interface{}) string {
+// Uppercase letters are converted to lowercase.
+func NormalizeZoneName(v interface{}) string {
 	var str string
 	switch value := v.(type) {
 	case *string:
@@ -568,7 +571,7 @@ func TrimTrailingPeriod(v interface{}) string {
 		return str
 	}
 
-	return strings.TrimSuffix(str, ".")
+	return strings.ToLower(strings.TrimSuffix(str, "."))
 }
 
 func findNameServers(ctx context.Context, conn *route53.Route53, zoneId string, zoneName string) ([]string, error) {

internal/service/route53/zone_data_source.go

@@ -123,7 +123,7 @@ func dataSourceZoneRead(ctx context.Context, d *schema.ResourceData, meta interf
 				hostedZoneFound = hostedZone
 				break
 				// we check if the name is the same as requested and if private zone field is the same as requested or if there is a vpc_id
-			} else if (TrimTrailingPeriod(aws.StringValue(hostedZone.Name)) == TrimTrailingPeriod(name)) && (aws.BoolValue(hostedZone.Config.PrivateZone) == d.Get("private_zone").(bool) || (aws.BoolValue(hostedZone.Config.PrivateZone) && vpcIdExists)) {
+			} else if (NormalizeZoneName(aws.StringValue(hostedZone.Name)) == NormalizeZoneName(name)) && (aws.BoolValue(hostedZone.Config.PrivateZone) == d.Get("private_zone").(bool) || (aws.BoolValue(hostedZone.Config.PrivateZone) && vpcIdExists)) {
 				matchingVPC := false
 				if vpcIdExists {
 					reqHostedZone := &route53.GetHostedZoneInput{}
@@ -178,7 +178,7 @@ func dataSourceZoneRead(ctx context.Context, d *schema.ResourceData, meta interf
 	d.Set("zone_id", idHostedZone)
 	// To be consistent with other AWS services (e.g. ACM) that do not accept a trailing period,
 	// we remove the suffix from the Hosted Zone Name returned from the API
-	d.Set("name", TrimTrailingPeriod(aws.StringValue(hostedZoneFound.Name)))
+	d.Set("name", NormalizeZoneName(aws.StringValue(hostedZoneFound.Name)))
 	d.Set("comment", hostedZoneFound.Config.Comment)
 	d.Set("private_zone", hostedZoneFound.Config.PrivateZone)
 	d.Set("caller_reference", hostedZoneFound.CallerReference)

internal/service/route53/zone_test.go

@@ -60,7 +60,7 @@ func TestCleanChangeID(t *testing.T) {
 	}
 }
 
-func TestTrimTrailingPeriod(t *testing.T) {
+func TestNormalizeZoneName(t *testing.T) {
 	t.Parallel()
 
 	cases := []struct {
@@ -70,17 +70,22 @@ func TestTrimTrailingPeriod(t *testing.T) {
 		{"example.com", "example.com"},
 		{"example.com.", "example.com"},
 		{"www.example.com.", "www.example.com"},
+		{"www.ExAmPlE.COM.", "www.example.com"},
 		{"", ""},
 		{".", "."},
 		{aws.String("example.com"), "example.com"},
 		{aws.String("example.com."), "example.com"},
+		{aws.String("www.example.com."), "www.example.com"},
+		{aws.String("www.ExAmPlE.COM."), "www.example.com"},
+		{aws.String(""), ""},
+		{aws.String("."), "."},
 		{(*string)(nil), ""},
 		{42, ""},
 		{nil, ""},
 	}
 
 	for _, tc := range cases {
-		actual := tfroute53.TrimTrailingPeriod(tc.Input)
+		actual := tfroute53.NormalizeZoneName(tc.Input)
 		if actual != tc.Output {
 			t.Fatalf("input: %s\noutput: %s", tc.Input, actual)
 		}