remove send_empty_value for max_ttl (#5456) (#10572)

* remove send_empty_value for max_ttl

* add a test

Signed-off-by: Modular Magician <[email protected]>

Author: modular-magician

.changelog/5456.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+compute: fixed a bug when `cache_mode` is set to FORCE_CACHE_ALL on `google_compute_backend_bucket`
+```

google/resource_compute_backend_bucket.go

@@ -713,7 +713,7 @@ func expandComputeBackendBucketCdnPolicy(v interface{}, d TerraformResourceData,
 	transformedMaxTtl, err := expandComputeBackendBucketCdnPolicyMaxTtl(original["max_ttl"], d, config)
 	if err != nil {
 		return nil, err
-	} else {
+	} else if val := reflect.ValueOf(transformedMaxTtl); val.IsValid() && !isEmptyValue(val) {
 		transformed["maxTtl"] = transformedMaxTtl
 	}
 

google/resource_compute_backend_bucket_test.go

@@ -68,7 +68,7 @@ func TestAccComputeBackendBucket_withCdnPolicy(t *testing.T) {
 				ImportStateVerify: true,
 			},
 			{
-				Config: testAccComputeBackendBucket_withCdnPolicy2(backendName, storageName, 0, 404, 0, 0),
+				Config: testAccComputeBackendBucket_withCdnPolicy2(backendName, storageName, 0, 404, 86400, 0),
 			},
 			{
 				ResourceName:      "google_compute_backend_bucket.foobar",
@@ -83,6 +83,14 @@ func TestAccComputeBackendBucket_withCdnPolicy(t *testing.T) {
 				ImportState:       true,
 				ImportStateVerify: true,
 			},
+			{
+				Config: testAccComputeBackendBucket_withCdnPolicy3(backendName, storageName, 0, 404, 0, 0),
+			},
+			{
+				ResourceName:      "google_compute_backend_bucket.foobar",
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
 		},
 	})
 }
@@ -165,3 +173,31 @@ resource "google_storage_bucket" "bucket" {
 }
 `, backendName, age, max_ttl, ttl, ttl, ttl, code, ttl, storageName)
 }
+
+func testAccComputeBackendBucket_withCdnPolicy3(backendName, storageName string, age, code, max_ttl, ttl int) string {
+	return fmt.Sprintf(`
+resource "google_compute_backend_bucket" "foobar" {
+  name        = "%s"
+  bucket_name = google_storage_bucket.bucket.name
+  enable_cdn  = true
+  cdn_policy {
+	cache_mode                   = "FORCE_CACHE_ALL"
+	signed_url_cache_max_age_sec = %d
+	max_ttl                      = %d
+	default_ttl                  = %d
+	client_ttl                   = %d
+	serve_while_stale            = %d
+	negative_caching_policy {
+		code = %d
+		ttl = %d
+	}
+	negative_caching = true
+  }
+}
+
+resource "google_storage_bucket" "bucket" {
+  name     = "%s"
+  location = "EU"
+}
+`, backendName, age, max_ttl, ttl, ttl, ttl, code, ttl, storageName)
+}