Fix deletion not found handling in the delete operation and adding re…

…lated tests (hashicorp#2592)

* Fix deletion not found handling and add related tests

* Adding changelog entry

* Adding license header

* Adding refernece to manifest resource / fixing return statement outside of else block

.changelog/2592.txt

@@ -0,0 +1,3 @@
+```release-note:enhancement
+`kubernetes_manifest` - handling "404 Not Found" errors during the deletion of Kubernetes resources, particularly in cases where the resource may have already been deleted by an operator managing the CRD before Terraform attempts to delete it.
+```

manifest/provider/apply.go

@@ -540,16 +540,25 @@ func (s *RawProviderServer) ApplyResourceChange(ctx context.Context, req *tfprot
 
 		err = rs.Delete(ctxDeadline, rname, metav1.DeleteOptions{})
 		if err != nil {
-			rn := types.NamespacedName{Namespace: rnamespace, Name: rname}.String()
-			resp.Diagnostics = append(resp.Diagnostics,
-				&tfprotov5.Diagnostic{
-					Severity: tfprotov5.DiagnosticSeverityError,
-					Summary:  fmt.Sprintf("Error deleting resource %s: %s", rn, err),
-					Detail:   err.Error(),
-				})
+			if apierrors.IsNotFound(err) {
+				s.logger.Trace("[ApplyResourceChange][Delete]", "Resource is already deleted")
+
+				resp.Diagnostics = append(resp.Diagnostics,
+					&tfprotov5.Diagnostic{
+						Severity: tfprotov5.DiagnosticSeverityWarning,
+						Summary:  fmt.Sprintf("Resource %q was already deleted", rname),
+						Detail:   fmt.Sprintf("The resource %q was not found in the Kubernetes API. This may be due to the resource being already deleted.", rname),
+					})
+			} else {
+				resp.Diagnostics = append(resp.Diagnostics,
+					&tfprotov5.Diagnostic{
+						Severity: tfprotov5.DiagnosticSeverityError,
+						Summary:  fmt.Sprintf("Error deleting resource %s: %s", rname, err),
+						Detail:   err.Error(),
+					})
+			}
 			return resp, nil
 		}
-
 		// wait for delete
 		for {
 			if time.Now().After(deadline) {

manifest/test/acceptance/delete_not_found_test.go

@@ -0,0 +1,77 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+//go:build acceptance
+// +build acceptance
+
+package acceptance
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/hashicorp/go-hclog"
+	"github.com/hashicorp/terraform-provider-kubernetes/manifest/provider"
+	"github.com/hashicorp/terraform-provider-kubernetes/manifest/test/helper/kubernetes"
+)
+
+func TestKubernetesManifest_DeletionNotFound(t *testing.T) {
+	ctx := context.Background()
+
+	reattachInfo, err := provider.ServeTest(ctx, hclog.Default(), t)
+	if err != nil {
+		t.Fatalf("Failed to create provider instance: %v", err)
+	}
+
+	name := randName()
+	namespace := randName()
+
+	tf := tfhelper.RequireNewWorkingDir(ctx, t)
+	tf.SetReattachInfo(ctx, reattachInfo)
+
+	k8shelper.CreateNamespace(t, namespace)
+	t.Logf("Verifying if namespace %s exists", namespace)
+	k8shelper.AssertResourceExists(t, "v1", "namespaces", namespace)
+
+	defer func() {
+		tf.Destroy(ctx)
+		tf.Close()
+		k8shelper.DeleteResource(t, namespace, kubernetes.NewGroupVersionResource("v1", "namespaces"))
+		k8shelper.AssertResourceDoesNotExist(t, "v1", "namespaces", namespace)
+	}()
+
+	tfvars := TFVARS{
+		"namespace": namespace,
+		"name":      name,
+	}
+
+	// Load the Terraform config that will create the ConfigMap
+	tfconfig := loadTerraformConfig(t, "DeleteNotFoundTest/resource.tf", tfvars)
+	tf.SetConfig(ctx, tfconfig)
+
+	t.Log("Applying Terraform configuration to create ConfigMap")
+	if err := tf.Apply(ctx); err != nil {
+		t.Fatalf("Terraform apply failed: %v", err)
+	}
+
+	state, err := tf.State(ctx)
+	if err != nil {
+		t.Fatalf("Failed to retrieve Terraform state: %v", err)
+	}
+	t.Logf("Terraform state: %v", state)
+
+	time.Sleep(2 * time.Second)
+
+	t.Logf("Checking if ConfigMap %s in namespace %s was created", name, namespace)
+	k8shelper.AssertNamespacedResourceExists(t, "v1", "configmaps", namespace, name)
+
+	// Simulating the deletion of the resource outside of Terraform
+	k8shelper.DeleteNamespacedResource(t, name, namespace, kubernetes.NewGroupVersionResource("v1", "configmaps"))
+
+	// Running tf destroy in order to check if we are handling "404 Not Found" gracefully
+	tf.Destroy(ctx)
+
+	// Ensuring that the ConfigMap no longer exists
+	k8shelper.AssertNamespacedResourceDoesNotExist(t, "v1", "configmaps", namespace, name)
+}

manifest/test/acceptance/testdata/DeleteNotFoundTest/resource.tf

@@ -0,0 +1,16 @@
+# Copyright (c) HashiCorp, Inc.
+# SPDX-License-Identifier: MPL-2.0
+resource "kubernetes_manifest" "test" {
+  manifest = {
+    "apiVersion" = "v1"
+    "kind"       = "ConfigMap"
+    "metadata" = {
+      "name"      = var.name
+      "namespace" = var.namespace
+    }
+    "data" = {
+      "foo" = "bar"
+    }
+  }
+}
+

manifest/test/acceptance/testdata/DeleteNotFoundTest/variables.tf

@@ -0,0 +1,19 @@
+# Copyright (c) HashiCorp, Inc.
+# SPDX-License-Identifier: MPL-2.0
+
+# These variable declarations are only used for interactive testing.
+# The test code will template in different variable declarations with a default value when running the test.
+#
+# To set values for interactive runs, create a var-file and set values in it. 
+# If the name of the var-file ends in '.auto.tfvars' (e.g. myvalues.auto.tfvars) 
+# it will be automatically picked up and used by Terraform.
+#
+# DO NOT check in any files named *.auto.tfvars when making changes to tests.
+
+variable "name" {
+  type = string
+}
+
+variable "namespace" {
+  type = string
+}