fix for scaling down to zero replica in Valkey (#14219) (#23412)

[upstream:f1c7e99d36445008da325054523d3ab07de0b6b1]

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

Author: modular-magician

.changelog/14219.txt

@@ -0,0 +1,3 @@
+```release-note:enhancement
+memorystore: added the ability to set the `replica_count`field  in `google_memorystore_instance` to zero.
+```

google/services/memorystore/resource_memorystore_instance.go

@@ -953,7 +953,7 @@ func resourceMemorystoreInstanceCreate(d *schema.ResourceData, meta interface{})
 	replicaCountProp, err := expandMemorystoreInstanceReplicaCount(d.Get("replica_count"), d, config)
 	if err != nil {
 		return err
-	} else if v, ok := d.GetOkExists("replica_count"); !tpgresource.IsEmptyValue(reflect.ValueOf(replicaCountProp)) && (ok || !reflect.DeepEqual(v, replicaCountProp)) {
+	} else if v, ok := d.GetOkExists("replica_count"); ok || !reflect.DeepEqual(v, replicaCountProp) {
 		obj["replicaCount"] = replicaCountProp
 	}
 	authorizationModeProp, err := expandMemorystoreInstanceAuthorizationMode(d.Get("authorization_mode"), d, config)
@@ -1291,7 +1291,7 @@ func resourceMemorystoreInstanceUpdate(d *schema.ResourceData, meta interface{})
 	replicaCountProp, err := expandMemorystoreInstanceReplicaCount(d.Get("replica_count"), d, config)
 	if err != nil {
 		return err
-	} else if v, ok := d.GetOkExists("replica_count"); !tpgresource.IsEmptyValue(reflect.ValueOf(v)) && (ok || !reflect.DeepEqual(v, replicaCountProp)) {
+	} else if v, ok := d.GetOkExists("replica_count"); ok || !reflect.DeepEqual(v, replicaCountProp) {
 		obj["replicaCount"] = replicaCountProp
 	}
 	shardCountProp, err := expandMemorystoreInstanceShardCount(d.Get("shard_count"), d, config)

google/services/memorystore/resource_memorystore_instance_test.go

@@ -30,7 +30,7 @@ import (
 	transport_tpg "github.com/hashicorp/terraform-provider-google/google/transport"
 )
 
-// Validate that replica count is updated for the instance
+// Validate that replica count is updated for the instance: 1->2->0
 func TestAccMemorystoreInstance_updateReplicaCount(t *testing.T) {
 	t.Parallel()
 
@@ -59,9 +59,18 @@ func TestAccMemorystoreInstance_updateReplicaCount(t *testing.T) {
 				ImportState:       true,
 				ImportStateVerify: true,
 			},
+			{
+				// update the replica count to 0
+				Config: createOrUpdateMemorystoreInstance(&InstanceParams{name: name, replicaCount: 0, shardCount: 3, preventDestroy: true, zoneDistributionMode: "MULTI_ZONE", deletionProtectionEnabled: false, maintenanceDay: "MONDAY", maintenanceHours: 1, maintenanceMinutes: 0, maintenanceSeconds: 0, maintenanceNanos: 0}),
+			},
+			{
+				ResourceName:      "google_memorystore_instance.test",
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
 			{
 				// clean up the resource
-				Config: createOrUpdateMemorystoreInstance(&InstanceParams{name: name, replicaCount: 2, shardCount: 3, preventDestroy: false, zoneDistributionMode: "MULTI_ZONE", deletionProtectionEnabled: false, maintenanceDay: "MONDAY", maintenanceHours: 1, maintenanceMinutes: 0, maintenanceSeconds: 0, maintenanceNanos: 0}),
+				Config: createOrUpdateMemorystoreInstance(&InstanceParams{name: name, replicaCount: 0, shardCount: 3, preventDestroy: false, zoneDistributionMode: "MULTI_ZONE", deletionProtectionEnabled: false, maintenanceDay: "MONDAY", maintenanceHours: 1, maintenanceMinutes: 0, maintenanceSeconds: 0, maintenanceNanos: 0}),
 			},
 		},
 	})