we could fail handilng the imsg and try to keep going on.  spotted by
breaking something else by accident and observing the regress hanging.

ok?

diff -s /home/op/w/got
commit - 53c2bfa8e1d5c3e128dcfcfd90c1a55099168eba
path + /home/op/w/got (staged changes)
blob - a2ef1cc69a5fc843bdf614504cb3e75f03180015
blob + 1d073e97037a9cb64129ca446a58b0f3fe2a2a62
--- gotd/session_write.c
+++ gotd/session_write.c
@@ -889,31 +889,31 @@ session_dispatch_repo_child(int fd, short event, void 
 		case GOTD_IMSG_REF_UPDATE:
 			err = recv_ref_update(&imsg);
 			if (err == NULL)
 				do_ref_update = 1;
 			break;
 		case GOTD_IMSG_NOTIFY:
 			err = recv_notification_content(&imsg);
 			if (err == NULL)
 				do_notify = 1;
 			break;
 		default:
 			log_debug("unexpected imsg %d", imsg.hdr.type);
 			break;
 		}
 
-		if (do_disconnect) {
+		if (do_disconnect || err) {
 			if (err)
 				disconnect_on_error(client, err);
 			else
 				disconnect(client);
 		} else {
 			struct gotd_session_notif *notif;
 
 			if (do_packfile_install)
 				err = install_pack(client,
 				    gotd_session.repo->path, &imsg);
 			else if (do_ref_updates)
 				err = begin_ref_updates(client, &imsg);
 			else if (do_ref_update)
 				err = update_ref(&shut, client,
 				    gotd_session.repo->path, &imsg);