Fix issue #15555: Set send_empty_value for noWrapper.writeMetadata

mmv1/products/pubsub/Subscription.yaml

@@ -262,13 +262,15 @@ properties:
         diff_suppress_func: 'tpgresource.IgnoreMissingKeyInMap("x-goog-version")'
       - !ruby/object:Api::Type::NestedObject
         name: 'noWrapper'
+        custom_flatten: 'templates/terraform/custom_flatten/pubsub_no_wrapper_write_metadata_flatten.go.erb'
         description: |
           When set, the payload to the push endpoint is not wrapped.Sets the
           `data` field as the HTTP body for delivery.
         properties:
           - !ruby/object:Api::Type::Boolean
             name: 'writeMetadata'
             required: true
+            send_empty_value: true
             description: |
               When true, writes the Pub/Sub message metadata to
               `x-goog-pubsub-<KEY>:<VAL>` headers of the HTTP request. Writes the

mmv1/templates/terraform/custom_flatten/pubsub_no_wrapper_write_metadata_flatten.go.erb

@@ -0,0 +1,30 @@
+<%# The license inside this block applies to this file.
+	# Copyright 2023 Google Inc.
+	# Licensed under the Apache License, Version 2.0 (the "License");
+	# you may not use this file except in compliance with the License.
+	# You may obtain a copy of the License at
+	#
+	#     http://www.apache.org/licenses/LICENSE-2.0
+	#
+	# Unless required by applicable law or agreed to in writing, software
+	# distributed under the License is distributed on an "AS IS" BASIS,
+	# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+	# See the License for the specific language governing permissions and
+	# limitations under the License.
+-%>
+func flatten<%= prefix -%><%= titlelize_property(property) -%>(v interface{}, d *schema.ResourceData, config *transport_tpg.Config) interface{} {
+	if v == nil {
+		return nil
+	}
+
+	original := v.(map[string]interface{})
+	transformed := make(map[string]interface{})
+
+	if original["writeMetadata"] == nil {
+		transformed["write_metadata"] = false
+	} else {
+		transformed["write_metadata"] = original["writeMetadata"]
+	}
+
+	return []interface{}{transformed}
+}

mmv1/third_party/terraform/services/pubsub/resource_pubsub_subscription_test.go

@@ -143,6 +143,31 @@ func TestAccPubsubSubscription_pushNoWrapper(t *testing.T) {
 	})
 }
 
+func TestAccPubsubSubscription_pushNoWrapperEmpty(t *testing.T) {
+	t.Parallel()
+
+	topicFoo := fmt.Sprintf("tf-test-topic-foo-%s", acctest.RandString(t, 10))
+	subscription := fmt.Sprintf("tf-test-sub-foo-%s", acctest.RandString(t, 10))
+	saAccount := fmt.Sprintf("tf-test-pubsub-%s", acctest.RandString(t, 10))
+
+	acctest.VcrTest(t, resource.TestCase{
+		PreCheck:                 func() { acctest.AccTestPreCheck(t) },
+		ProtoV5ProviderFactories: acctest.ProtoV5ProviderFactories(t),
+		CheckDestroy:             testAccCheckPubsubSubscriptionDestroyProducer(t),
+		Steps: []resource.TestStep{
+			{
+				Config: testAccPubsubSubscription_pushNoWrapperEmpty(topicFoo, saAccount, subscription),
+			},
+			{
+				ResourceName:      "google_pubsub_subscription.foo",
+				ImportStateId:     subscription,
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
+		},
+	})
+}
+
 // Context: hashicorp/terraform-provider-google#4993
 // This test makes a call to GET an subscription before it is actually created.
 // The PubSub API negative-caches responses so this tests we are
@@ -277,6 +302,45 @@ resource "google_pubsub_subscription" "foo" {
 `, saAccount, topicFoo, subscription)
 }
 
+func testAccPubsubSubscription_pushNoWrapperEmpty(topicFoo, saAccount, subscription string) string {
+	return fmt.Sprintf(`
+data "google_project" "project" { }
+
+resource "google_service_account" "pub_sub_service_account" {
+  account_id = "%s"
+}
+
+data "google_iam_policy" "admin" {
+  binding {
+    role = "roles/projects.topics.publish"
+
+    members = [
+      "serviceAccount:${google_service_account.pub_sub_service_account.email}",
+    ]
+  }
+}
+
+resource "google_pubsub_topic" "foo" {
+  name = "%s"
+}
+
+resource "google_pubsub_subscription" "foo" {
+  name                 = "%s"
+  topic                = google_pubsub_topic.foo.name
+  ack_deadline_seconds = 10
+  push_config {
+    push_endpoint = "https://${data.google_project.project.project_id}.appspot.com"
+    oidc_token {
+      service_account_email = google_service_account.pub_sub_service_account.email
+    }
+    no_wrapper {
+      write_metadata = false
+    }
+  }
+}
+`, saAccount, topicFoo, subscription)
+}
+
 func testAccPubsubSubscription_basic(topic, subscription, label string, deadline int, exactlyOnceDelivery bool) string {
 	return fmt.Sprintf(`
 resource "google_pubsub_topic" "foo" {