CA-217842: Replace instances of vm_lacks_feature_x with vm_lacks_feature

Rationale: This leads to less confusion when, for example, attempting to
migrate a VM leads to an error that the VM does not support suspend. The
lacking feature is currently always better defined by context than by the
error text itself, so let's make the error generic and rely on the
context to signify which feature is lacking.

Also, given that the shutdown/reboot features might be advertised by either
feature_poweroff,feature_reboot or feature_shutdown, this makes the
error raised less wrong.

Signed-off-by: Jon Ludlam <jonathan.ludlam@citrix.com>

Author: jonludlam

ocaml/idl/api_errors.ml

@@ -178,6 +178,7 @@ let vm_migrate_failed = "VM_MIGRATE_FAILED"
 let vm_missing_pv_drivers = "VM_MISSING_PV_DRIVERS"
 let vm_failed_shutdown_ack = "VM_FAILED_SHUTDOWN_ACKNOWLEDGMENT"
 let vm_old_pv_drivers = "VM_OLD_PV_DRIVERS"
+let vm_lacks_feature = "VM_LACKS_FEATURE"
 let vm_lacks_feature_shutdown = "VM_LACKS_FEATURE_SHUTDOWN"
 let vm_lacks_feature_suspend = "VM_LACKS_FEATURE_SUSPEND"
 let vm_lacks_feature_vcpu_hotplug = "VM_LACKS_FEATURE_VCPU_HOTPLUG"

ocaml/idl/datamodel.ml

@@ -677,6 +677,8 @@ let _ =
 	  ~doc:"You attempted an operation which needs the VM cooperative suspend feature on a VM which lacks it." ();
   error Api_errors.vm_lacks_feature_static_ip_setting [ "vm" ]
 	  ~doc:"You attempted an operation which needs the VM static-ip-setting feature on a VM which lacks it." ();
+  error Api_errors.vm_lacks_feature [ "vm" ]
+	  ~doc:"You attempted an operation on a VM which lacks the feature." ();
   error Api_errors.vm_is_template ["vm"]
     ~doc:"The operation attempted is not valid for a template VM" ();
   error Api_errors.other_operation_in_progress ["class"; "object"]

ocaml/xapi/xapi_vif.ml

@@ -145,7 +145,7 @@ let assert_has_feature_static_ip_setting ~__context ~self =
 		if List.assoc feature other <> "1" then
 			failwith "not found"
 	with _ ->
-		raise Api_errors.(Server_error (vm_lacks_feature_static_ip_setting, [Ref.string_of vm]))
+		raise Api_errors.(Server_error (vm_lacks_feature, [Ref.string_of vm]))
 
 let assert_no_locking_mode_conflict ~__context ~self kind address =
 	let vif_locking_mode = Db.VIF.get_locking_mode ~__context ~self in

ocaml/xapi/xapi_vm_lifecycle.ml

@@ -166,16 +166,16 @@ let check_op_for_feature ~__context ~vmr ~vmgmr ~power_state ~op ~ref ~strict =
 		match op with
 			| `clean_shutdown
 					when strict && lack_feature "feature-shutdown" && lack_feature "feature-poweroff"
-						-> some_err Api_errors.vm_lacks_feature_shutdown
+						-> some_err Api_errors.vm_lacks_feature
 			| `clean_reboot
 					when strict && lack_feature "feature-shutdown" && lack_feature "feature-reboot"
-						-> some_err Api_errors.vm_lacks_feature_shutdown
+						-> some_err Api_errors.vm_lacks_feature
 			| `changing_VCPUs_live
 					when lack_feature "feature-vcpu-hotplug"
-						-> some_err Api_errors.vm_lacks_feature_vcpu_hotplug
+						-> some_err Api_errors.vm_lacks_feature
 			| `suspend | `checkpoint | `pool_migrate | `migrate_send
 					when strict && lack_feature "feature-suspend"
-						-> some_err Api_errors.vm_lacks_feature_suspend
+						-> some_err Api_errors.vm_lacks_feature
 			| _ -> None
 	(* N.B. In the pattern matching above, "pat1 | pat2 | pat3" counts as
 	 * one pattern, and the whole thing can be guarded by a "when" clause. *)