Fix subnetwork with DiffSuppressFunc

mmv1/third_party/terraform/resources/resource_compute_router_interface.go.erb

@@ -78,13 +78,14 @@ func resourceComputeRouterInterface() *schema.Resource {
 				Description:  `The regional private internal IP address that is used to establish BGP sessions to a VM instance acting as a third-party Router Appliance. Changing this forces a new interface to be created.`,
 			},
 			"subnetwork": {
-				Type:          schema.TypeString,
-				Optional:      true,
-				Computed:      true,
-				ForceNew:      true,
-				AtLeastOneOf:  []string{"ip_range", "interconnect_attachment", "subnetwork", "vpn_tunnel"},
-				ConflictsWith: []string{"interconnect_attachment", "vpn_tunnel"},
-				Description:   `The URI of the subnetwork resource that this interface belongs to, which must be in the same region as the Cloud Router. Changing this forces a new interface to be created. Only one of subnetwork, interconnect_attachment or vpn_tunnel can be specified.`,
+				Type:             schema.TypeString,
+				Optional:         true,
+				Computed:         true,
+				ForceNew:         true,
+				DiffSuppressFunc: compareSelfLinkOrResourceName,
+				AtLeastOneOf:     []string{"ip_range", "interconnect_attachment", "subnetwork", "vpn_tunnel"},
+				ConflictsWith:    []string{"interconnect_attachment", "vpn_tunnel"},
+				Description:      `The URI of the subnetwork resource that this interface belongs to, which must be in the same region as the Cloud Router. Changing this forces a new interface to be created. Only one of subnetwork, interconnect_attachment or vpn_tunnel can be specified.`,
 			},
 			"project": {
 				Type:        schema.TypeString,