Revert "Allow updating guest accelerator count to 0 on compute_instance" (#15594)

Author: c2thorn

mmv1/third_party/terraform/services/compute/resource_compute_instance.go.tmpl

@@ -3376,23 +3376,12 @@ func suppressEmptyGuestAcceleratorDiff(_ context.Context, d *schema.ResourceDiff
 		return nil
 	}
 
-	// Check if old had a non-zero count
-	if len(old) > 0 {
-		if apiAccel, ok := old[0].(map[string]interface{}); ok {
-			if oldCount, ok := apiAccel["count"].(int); ok && oldCount != 0 {
-				// Old count wasn't 0, so don't clear the diff
-				return nil
-			}
-		}
-	}
-
-	// Check new accelerator configuration
-	configAccel, ok := new[0].(map[string]interface{})
+	firstAccel, ok := new[0].(map[string]interface{})
 	if !ok {
 		return fmt.Errorf("Unable to type assert guest accelerator")
 	}
 
-	if configAccel["count"].(int) == 0 {
+	if firstAccel["count"].(int) == 0 {
 		if err := d.Clear("guest_accelerator"); err != nil {
 			return err
 		}

mmv1/third_party/terraform/services/compute/resource_compute_instance_test.go.tmpl

@@ -2504,16 +2504,10 @@ func TestAccComputeInstance_guestAccelerator(t *testing.T) {
 					testAccCheckComputeInstanceHasGuestAccelerator(&instance, "nvidia-tesla-t4", 1),
 				),
 			},
-			{
-				Config:             testAccComputeInstance_guestAccelerator(instanceName, 0),
-				Check: resource.ComposeTestCheckFunc(
-					testAccCheckComputeInstanceExists(t, "google_compute_instance.foobar", &instance),
-					testAccCheckComputeInstanceHasGuestAccelerator(&instance, "nvidia-tesla-t4", 0),
-				),
-			},
 			computeInstanceImportStep("us-east1-d", instanceName, []string{"metadata.baz", "metadata.foo"}),
 		},
 	})
+
 }
 
 func TestAccComputeInstance_guestAcceleratorSkip(t *testing.T) {
@@ -5847,9 +5841,6 @@ func testAccCheckComputeInstanceHasMultiNic(instance *compute.Instance) resource
 func testAccCheckComputeInstanceHasGuestAccelerator(instance *compute.Instance, acceleratorType string, acceleratorCount int64) resource.TestCheckFunc {
 	return func(s *terraform.State) error {
 		if len(instance.GuestAccelerators) != 1 {
-			if int(acceleratorCount) == 0 && len(instance.GuestAccelerators) == 0 {
-				return nil
-			}
 			return fmt.Errorf("Expected only one guest accelerator")
 		}