feat: (storage) remove cache value

mmv1/products/storage/AnywhereCache.yaml

@@ -43,6 +43,7 @@ async:
     resource_inside_response: true
 autogen_async: false
 custom_code:
+  constants: templates/terraform/constants/storage_anywhere_cache.go.tmpl
   custom_create: templates/terraform/custom_create/storage_anywhere_cache.go.tmpl
   custom_update: templates/terraform/custom_update/storage_anywhere_cache.go.tmpl
 samples:
@@ -71,11 +72,16 @@ properties:
     description: The zone in which the cache instance needs to be created. For example, `us-central1-a.`
   - name: admissionPolicy
     type: Enum
+    default_value: admit-on-first-miss
+    deprecation_message: '`admit-on-second-miss` is deprecated and will be removed in a future major release. The backend will ignore this attribute and treat it as `admit-on-first-miss`.'
+    description: |
+      The cache admission policy dictates whether a block should be inserted upon a cache miss.
+      Note: "admit-on-second-miss" is deprecated and will fallback to "admit-on-first-miss".
     enum_values:
       - admit-on-first-miss
       - admit-on-second-miss
-    default_value: admit-on-first-miss
-    description: The cache admission policy dictates whether a block should be inserted upon a cache miss.
+    diff_suppress_func: StorageAnywhereCacheAdmissionPolicyDiffSuppress
+    custom_expand: templates/terraform/custom_expand/storage_anywhere_cache_admission_policy.go.tmpl
   - name: ttl
     type: String
     default_value: 86400s

mmv1/templates/terraform/constants/storage_anywhere_cache.go.tmpl

@@ -0,0 +1,21 @@
+{{/*
+	The license inside this block applies to this file
+	Copyright 2026 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.
+*/ -}}
+// Suppresses diffs for Anywhere Cache admission policy where "admit-on-second-miss"
+// is deprecated and falls back to "admit-on-first-miss".
+func StorageAnywhereCacheAdmissionPolicyDiffSuppress(_, old, new string, _ *schema.ResourceData) bool {
+	if old == new {
+		return true
+	}
+	return (old == "admit-on-first-miss" && new == "admit-on-second-miss") ||
+		(old == "admit-on-second-miss" && new == "admit-on-first-miss")
+}

mmv1/templates/terraform/custom_expand/storage_anywhere_cache_admission_policy.go.tmpl

@@ -0,0 +1,22 @@
+{{/*
+	The license inside this block applies to this file
+	Copyright 2026 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 expand{{$.GetPrefix}}{{$.TitlelizeProperty}}(v interface{}, d tpgresource.TerraformResourceData, config *transport_tpg.Config) (interface{}, error) {
+	if v == nil {
+		return nil, nil
+	}
+	s := v.(string)
+	if s == "admit-on-second-miss" {
+		return "admit-on-first-miss", nil
+	}
+	return s, nil
+}