fix: Allow ROOT as a Repository Creation Template prefix

.changelog/38685.txt

@@ -0,0 +1,7 @@
+```release-note:bug
+resource/aws_ecr_repository_creation_template: Support `ROOT` as a valid value for `prefix`
+```
+
+```release-note:bug
+data-source/aws_ecr_repository_creation_template: Support `ROOT` as a valid value for `prefix`
+```

internal/service/ecr/repository_creation_template.go

@@ -106,8 +106,8 @@ func resourceRepositoryCreationTemplate() *schema.Resource {
 				ValidateFunc: validation.All(
 					validation.StringLenBetween(2, 30),
 					validation.StringMatch(
-						regexache.MustCompile(`(?:[a-z0-9]+(?:[._-][a-z0-9]+)*/)*[a-z0-9]+(?:[._-][a-z0-9]+)*`),
-						"must only include alphanumeric, underscore, period, hyphen, or slash characters"),
+						regexache.MustCompile(`(?:ROOT|(?:[a-z0-9]+(?:[._-][a-z0-9]+)*/)*[a-z0-9]+(?:[._-][a-z0-9]+)*)`),
+						"must only include alphanumeric, underscore, period, hyphen, or slash characters, or be the string `ROOT`"),
 				),
 			},
 			"registry_id": {

internal/service/ecr/repository_creation_template_data_source.go

@@ -70,8 +70,8 @@ func dataSourceRepositoryCreationTemplate() *schema.Resource {
 				ValidateFunc: validation.All(
 					validation.StringLenBetween(2, 30),
 					validation.StringMatch(
-						regexache.MustCompile(`(?:[a-z0-9]+(?:[._-][a-z0-9]+)*/)*[a-z0-9]+(?:[._-][a-z0-9]+)*`),
-						"must only include alphanumeric, underscore, period, hyphen, or slash characters"),
+						regexache.MustCompile(`(?:ROOT|(?:[a-z0-9]+(?:[._-][a-z0-9]+)*/)*[a-z0-9]+(?:[._-][a-z0-9]+)*)`),
+						"must only include alphanumeric, underscore, period, hyphen, or slash characters, or be the string `ROOT`"),
 				),
 			},
 			"registry_id": {

internal/service/ecr/repository_creation_template_data_source_test.go

@@ -47,6 +47,25 @@ func TestAccECRRepositoryCreationTemplateDataSource_basic(t *testing.T) {
 	})
 }
 
+func TestAccECRRepositoryCreationTemplateDataSource_root(t *testing.T) {
+	ctx := acctest.Context(t)
+	dataSource := "data.aws_ecr_repository_creation_template.root"
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:                 func() { acctest.PreCheck(ctx, t) },
+		ErrorCheck:               acctest.ErrorCheck(t, names.ECRServiceID),
+		ProtoV5ProviderFactories: acctest.ProtoV5ProviderFactories,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccRepositoryCreationTemplateDataSourceConfig_root(),
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckResourceAttr(dataSource, names.AttrPrefix, "ROOT"),
+				),
+			},
+		},
+	})
+}
+
 func testAccRepositoryCreationTemplateDataSourceConfig_basic(repositoryPrefix string) string {
 	return fmt.Sprintf(`
 resource "aws_ecr_repository_creation_template" "test" {
@@ -66,3 +85,19 @@ data "aws_ecr_repository_creation_template" "test" {
 }
 `, repositoryPrefix)
 }
+
+func testAccRepositoryCreationTemplateDataSourceConfig_root() string {
+	return `
+resource "aws_ecr_repository_creation_template" "root" {
+  prefix = "ROOT"
+
+  applied_for = [
+    "PULL_THROUGH_CACHE",
+  ]
+}
+
+data "aws_ecr_repository_creation_template" "root" {
+  prefix = aws_ecr_repository_creation_template.root.prefix
+}
+`
+}

internal/service/ecr/repository_creation_template_test.go

@@ -168,6 +168,26 @@ func TestAccECRRepositoryCreationTemplate_repository(t *testing.T) {
 	})
 }
 
+func TestAccECRRepositoryCreationTemplate_root(t *testing.T) {
+	ctx := acctest.Context(t)
+	resourceName := "aws_ecr_repository_creation_template.root"
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:                 func() { acctest.PreCheck(ctx, t) },
+		ErrorCheck:               acctest.ErrorCheck(t, names.ECRServiceID),
+		ProtoV5ProviderFactories: acctest.ProtoV5ProviderFactories,
+		CheckDestroy:             testAccCheckRepositoryCreationTemplateDestroy(ctx),
+		Steps: []resource.TestStep{
+			{
+				Config: testAccRepositoryCreationTemplateConfig_root(),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckRepositoryCreationTemplateExists(ctx, resourceName),
+				),
+			},
+		},
+	})
+}
+
 func testAccCheckRepositoryCreationTemplateDestroy(ctx context.Context) resource.TestCheckFunc {
 	return func(s *terraform.State) error {
 		conn := acctest.Provider.Meta().(*conns.AWSClient).ECRClient(ctx)
@@ -394,3 +414,15 @@ resource "aws_ecr_repository_creation_template" "test" {
 }
 `, repositoryPrefix)
 }
+
+func testAccRepositoryCreationTemplateConfig_root() string {
+	return `
+resource "aws_ecr_repository_creation_template" "root" {
+  prefix = "ROOT"
+
+  applied_for = [
+    "PULL_THROUGH_CACHE",
+  ]
+}
+`
+}

website/docs/r/ecr_repository_creation_template.html.markdown

@@ -88,7 +88,7 @@ EOT
 
 This resource supports the following arguments:
 
-* `prefix` - (Required, Forces new resource) The repository name prefix to match against.
+* `prefix` - (Required, Forces new resource) The repository name prefix to match against. Use `ROOT` to match any prefix that doesn't explicitly match another template.
 * `applied_for` - (Required) Which features this template applies to. Must contain one or more of `PULL_THROUGH_CACHE` or `REPLICATION`.
 * `custom_role_arn` - (Optional) A custom IAM role to use for repository creation. Required if using repository tags or KMS encryption.
 * `description` - (Optional) The description for this template.