From abf561e884d5cada505cb9e09beaebbd0e564245 Mon Sep 17 00:00:00 2001
From: zhihaos <zhihaos@google.com>
Date: Wed, 12 Nov 2025 12:59:01 -0800
Subject: [PATCH 1/2] Set update_mask to false to overwrite the instructions;

---
 mmv1/products/dialogflowcx/Playbook.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mmv1/products/dialogflowcx/Playbook.yaml b/mmv1/products/dialogflowcx/Playbook.yaml
index 6912742b2203..f666afa3d067 100644
--- a/mmv1/products/dialogflowcx/Playbook.yaml
+++ b/mmv1/products/dialogflowcx/Playbook.yaml
@@ -26,7 +26,7 @@ self_link: '{{parent}}/playbooks/{{name}}'
 create_url: '{{parent}}/playbooks'
 
 update_verb: 'PATCH'
-update_mask: true
+update_mask: false
 
 custom_code:
   pre_create: 'templates/terraform/pre_create/dialogflow_set_location.go.tmpl'

From 588ba2add464ccb73d8b1fe1ee7f6716acfb9729 Mon Sep 17 00:00:00 2001
From: Zhihao S <zhihaos@google.com>
Date: Wed, 12 Nov 2025 16:52:14 -0500
Subject: [PATCH 2/2] Use granular update mask custom code;

---
 mmv1/products/dialogflowcx/Playbook.yaml      |  4 +-
 ...owcx_playbook_granular_update_mask.go.tmpl | 38 +++++++++++++++++++
 2 files changed, 40 insertions(+), 2 deletions(-)
 create mode 100644 mmv1/templates/terraform/pre_update/dialogflowcx_playbook_granular_update_mask.go.tmpl

diff --git a/mmv1/products/dialogflowcx/Playbook.yaml b/mmv1/products/dialogflowcx/Playbook.yaml
index f666afa3d067..32ecd3e53690 100644
--- a/mmv1/products/dialogflowcx/Playbook.yaml
+++ b/mmv1/products/dialogflowcx/Playbook.yaml
@@ -26,12 +26,12 @@ self_link: '{{parent}}/playbooks/{{name}}'
 create_url: '{{parent}}/playbooks'
 
 update_verb: 'PATCH'
-update_mask: false
+update_mask: true
 
 custom_code:
   pre_create: 'templates/terraform/pre_create/dialogflow_set_location.go.tmpl'
   pre_read: 'templates/terraform/pre_create/dialogflow_set_location.go.tmpl'
-  pre_update: 'templates/terraform/pre_create/dialogflow_set_location.go.tmpl'
+  pre_update: 'templates/terraform/pre_update/dialogflowcx_playbook_granular_update_mask.go.tmpl'
   pre_delete: 'templates/terraform/pre_create/dialogflow_set_location.go.tmpl'
   custom_import: 'templates/terraform/custom_import/dialogflowcx_playbook.go.tmpl'
 
diff --git a/mmv1/templates/terraform/pre_update/dialogflowcx_playbook_granular_update_mask.go.tmpl b/mmv1/templates/terraform/pre_update/dialogflowcx_playbook_granular_update_mask.go.tmpl
new file mode 100644
index 000000000000..7720ad943b63
--- /dev/null
+++ b/mmv1/templates/terraform/pre_update/dialogflowcx_playbook_granular_update_mask.go.tmpl
@@ -0,0 +1,38 @@
+// extract location from the parent
+location := ""
+
+if parts := regexp.MustCompile(`locations\/([^\/]*)\/`).FindStringSubmatch(d.Get("parent").(string)); parts != nil {
+	location = parts[1]
+} else {
+	return fmt.Errorf(
+		"Saw %s when the parent is expected to contains location %s",
+		d.Get("parent"),
+		"projects/{{"{{"}}project{{"}}"}}/locations/{{"{{"}}location{{"}}"}}/...",
+	)
+}
+
+// only insert location into url if the base_url in products/dialogflowcx/product.yaml is used
+if strings.HasPrefix(url, "https://-dialogflow.googleapis.com/v3/") {
+	url = strings.Replace(url, "-dialogflow", fmt.Sprintf("%s-dialogflow", location), 1)
+}
+
+// The generated code sets the wrong masks for the following fields.
+newUpdateMask := []string{}
+if d.HasChange("instruction.0.steps") {
+    newUpdateMask = append(newUpdateMask, "instruction.steps")
+}
+if d.HasChange("instruction.0.guidelines") {
+    newUpdateMask = append(newUpdateMask, "instruction.guidelines")
+}
+// Pull out any other set fields from the generated mask.
+for _, mask := range updateMask {
+    if mask == "instruction" {
+        continue
+    }
+    newUpdateMask = append(newUpdateMask, mask)
+}
+// Overwrite the previously set mask.
+url, err = transport_tpg.AddQueryParams(url, map[string]string{"updateMask": strings.Join(newUpdateMask, ",")})
+if err != nil {
+    return err
+}