checkpoint: don't let nm_checkpoint_new() fail

We already do error checking in nm_checkpoint_manager_create(). No need
to split it in two places. Let all error conditions be handled by
nm_checkpoint_manager_create() first, and then once we decide all is
good, nm_checkpoint_new() can no longer fail.

src/nm-checkpoint-manager.c

@@ -161,6 +161,14 @@ nm_checkpoint_manager_create (NMCheckpointManager *self,
 		}
 	}
 
+	if (!devices->len) {
+		g_set_error_literal (error,
+		                     NM_MANAGER_ERROR,
+		                     NM_MANAGER_ERROR_INVALID_ARGUMENTS,
+		                     "no device available");
+		return NULL;
+	}
+
 	if (!NM_FLAGS_HAS (flags, NM_CHECKPOINT_CREATE_FLAG_DESTROY_ALL)) {
 		for (i = 0; i < devices->len; i++) {
 			device = devices->pdata[i];
@@ -175,9 +183,7 @@ nm_checkpoint_manager_create (NMCheckpointManager *self,
 		}
 	}
 
-	checkpoint = nm_checkpoint_new (manager, devices, rollback_timeout, flags, error);
-	if (!checkpoint)
-		return NULL;
+	checkpoint = nm_checkpoint_new (manager, devices, rollback_timeout, flags);
 
 	if (NM_FLAGS_HAS (flags, NM_CHECKPOINT_CREATE_FLAG_DESTROY_ALL))
 		nm_checkpoint_manager_destroy_all (self);

src/nm-checkpoint.c

@@ -495,7 +495,7 @@ nm_checkpoint_init (NMCheckpoint *self)
 
 NMCheckpoint *
 nm_checkpoint_new (NMManager *manager, GPtrArray *devices, guint32 rollback_timeout_s,
-                   NMCheckpointCreateFlags flags, GError **error)
+                   NMCheckpointCreateFlags flags)
 {
 	NMCheckpoint *self;
 	NMCheckpointPrivate *priv;
@@ -505,15 +505,7 @@ nm_checkpoint_new (NMManager *manager, GPtrArray *devices, guint32 rollback_time
 
 	g_return_val_if_fail (manager, NULL);
 	g_return_val_if_fail (devices, NULL);
-	g_return_val_if_fail (!error || !*error, NULL);
-
-	if (!devices->len) {
-		g_set_error_literal (error,
-		                     NM_MANAGER_ERROR,
-		                     NM_MANAGER_ERROR_INVALID_ARGUMENTS,
-		                     "no device available");
-		return NULL;
-	}
+	g_return_val_if_fail (devices->len > 0, NULL);
 
 	self = g_object_new (NM_TYPE_CHECKPOINT, NULL);
 

src/nm-checkpoint.h

@@ -48,7 +48,7 @@ typedef struct _NMCheckpointClass NMCheckpointClass;
 GType nm_checkpoint_get_type (void);
 
 NMCheckpoint *nm_checkpoint_new (NMManager *manager, GPtrArray *devices, guint32 rollback_timeout,
-                                 NMCheckpointCreateFlags flags, GError **error);
+                                 NMCheckpointCreateFlags flags);
 
 typedef void (*NMCheckpointTimeoutCallback) (NMCheckpoint *self,
                                              gpointer user_data);