diff --git a/contrib/chg/chg.c b/contrib/chg/chg.c
--- a/contrib/chg/chg.c
+++ b/contrib/chg/chg.c
@@ -269,6 +269,9 @@ static hgclient_t *retryconnectcmdserver
 
 cleanup:
 	if (WIFEXITED(pst)) {
+		if (WEXITSTATUS(pst) == 0)
+			abortmsg("could not connect to cmdserver "
+				 "(exited with status 0)");
 		debugmsg("cmdserver exited with status %d", WEXITSTATUS(pst));
 		exit(WEXITSTATUS(pst));
 	} else if (WIFSIGNALED(pst)) {