Validate helm_release.name during plan to catch invalid release names in plan time

.changelog/1622.txt

@@ -0,0 +1,3 @@
+```release-note:enhancement
+`helm_release`: Include validation of `name` during plan phase to catch invalid Helm release names early
+```

helm/resource_helm_release.go

@@ -11,6 +11,7 @@ import (
 	"net/url"
 	"os"
 	pathpkg "path"
+	"regexp"
 	"strings"
 	"time"
 
@@ -1665,6 +1666,8 @@ func checkChartDependencies(ctx context.Context, model *HelmReleaseModel, c *cha
 	return false, diags
 }
 
+var helmReleaseNameRegexp = regexp.MustCompile(`^[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*$`)
+
 func (r *HelmRelease) ModifyPlan(ctx context.Context, req resource.ModifyPlanRequest, resp *resource.ModifyPlanResponse) {
 	if req.Plan.Raw.IsNull() {
 		// resource is being destroyed
@@ -1675,6 +1678,20 @@ func (r *HelmRelease) ModifyPlan(ctx context.Context, req resource.ModifyPlanReq
 	if resp.Diagnostics.HasError() {
 		return
 	}
+	if !plan.Name.IsNull() {
+		name := plan.Name.ValueString()
+		if !helmReleaseNameRegexp.MatchString(name) {
+			resp.Diagnostics.AddError(
+				"Invalid Helm Release Name",
+				fmt.Sprintf(
+					"Release name %q is invalid. Must match regex %s",
+					name,
+					helmReleaseNameRegexp.String(),
+				),
+			)
+			return
+		}
+	}
 	var state *HelmReleaseModel
 	resp.Diagnostics.Append(req.State.Get(ctx, &state)...)
 	if resp.Diagnostics.HasError() {

helm/resource_helm_release_test.go

@@ -767,33 +767,6 @@ func TestAccResourceRelease_namespaceDoesNotExist(t *testing.T) {
 		},
 	})
 }
-
-func TestAccResourceRelease_invalidName(t *testing.T) {
-	namespace := createRandomNamespace(t)
-	defer deleteNamespace(t, namespace)
-
-	broken := fmt.Sprintf(`
-	resource "helm_release" "test" {
-		name        = "1nva&lidname$"
-		namespace   = %q
-		repository  = %q
-		chart       = "test-chart"
-	}`, namespace, testRepositoryURL)
-
-	resource.Test(t, resource.TestCase{
-		// PreCheck:                 func() { testAccPreCheck(t) },
-		ProtoV6ProviderFactories: protoV6ProviderFactories(),
-		// CheckDestroy:             testAccCheckHelmReleaseDestroy(namespace),
-		Steps: []resource.TestStep{
-			{
-				Config:             broken,
-				ExpectError:        regexp.MustCompile("invalid release name"),
-				ExpectNonEmptyPlan: true,
-			},
-		},
-	})
-}
-
 func TestAccResourceRelease_createNamespace(t *testing.T) {
 	name := randName("create-namespace")
 	namespace := randName("helm-created-namespace")
@@ -823,6 +796,29 @@ func TestAccResourceRelease_createNamespace(t *testing.T) {
 		},
 	})
 }
+func TestAccResourceRelease_planValidationInvalidName(t *testing.T) {
+	invalidNames := []string{
+		"invalid_helm_release_name",
+		"ThisHelmRelease",
+	}
+	namespace := createRandomNamespace(t)
+	defer deleteNamespace(t, namespace)
+
+	for index, name := range invalidNames {
+		t.Run(fmt.Sprintf("invalid_name_%d", index), func(t *testing.T) {
+			resource.Test(t, resource.TestCase{
+				ProtoV6ProviderFactories: protoV6ProviderFactories(),
+				Steps: []resource.TestStep{
+					{
+						Config:      testAccHelmReleaseConfigInvalidNamePlan(testResourceName, namespace, name),
+						PlanOnly:    true,
+						ExpectError: regexp.MustCompile(`Invalid Helm Release Name`),
+					},
+				},
+			})
+		})
+	}
+}
 
 func TestAccResourceRelease_LocalVersion(t *testing.T) {
 	// NOTE this test confirms that the user is warned if their configured
@@ -894,6 +890,17 @@ func testAccHelmReleaseConfigBasic(resource, ns, name, version string) string {
 	`, resource, name, ns, testRepositoryURL, version)
 }
 
+func testAccHelmReleaseConfigInvalidNamePlan(resource, ns, name string) string {
+	return fmt.Sprintf(`
+        resource "helm_release" "%s" {
+            name       = %q
+            namespace  = %q
+            repository = %q
+            chart      = "test-chart"
+        }
+    `, resource, name, ns, testRepositoryURL)
+}
+
 func testAccHelmReleaseConfig_set_wo(resource, ns, name, version string) string {
 	return fmt.Sprintf(`
 		resource "helm_release" "%s" {