data-device: fix crash when setting the same selection twice

types/data_device/wlr_data_device.c

@@ -167,6 +167,11 @@ static void seat_handle_selection_source_destroy(
 
 void wlr_seat_set_selection(struct wlr_seat *seat,
 		struct wlr_data_source *source, uint32_t serial) {
+	if (seat->selection_source == source) {
+		seat->selection_serial = serial;
+		return;
+	}
+
 	if (seat->selection_source) {
 		wl_list_remove(&seat->selection_source_destroy.link);
 		wlr_data_source_destroy(seat->selection_source);

types/wlr_primary_selection.c

@@ -69,10 +69,8 @@ static void seat_handle_primary_selection_source_destroy(
 
 void wlr_seat_set_primary_selection(struct wlr_seat *seat,
 		struct wlr_primary_selection_source *source, uint32_t serial) {
-	if (seat->primary_selection_source != NULL &&
+	if (seat->primary_selection_source == source) {
-			seat->primary_selection_serial - serial < UINT32_MAX / 2) {
+		seat->primary_selection_serial = serial;
-		wlr_log(WLR_DEBUG, "Rejecting set_selection request, invalid serial "
-			"(%"PRIu32" <= %"PRIu32")", serial, seat->primary_selection_serial);
 		return;
 	}