From 594d7266af6c0a899e5218df444178c16327563e Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Mon, 8 Dec 2014 13:26:55 -0200
Subject: [PATCH] 'assert' checks that it has (at least) one parameter +
 'assert' ensures it passes only one value to 'error'

---
 lbaselib.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/lbaselib.c b/lbaselib.c
index 5c73e4f8..902143ea 100644
--- a/lbaselib.c
+++ b/lbaselib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lbaselib.c,v 1.306 2014/11/02 19:19:04 roberto Exp roberto $
+** $Id: lbaselib.c,v 1.307 2014/11/10 14:25:52 roberto Exp roberto $
 ** Basic library
 ** See Copyright Notice in lua.h
 */
@@ -388,9 +388,10 @@ static int luaB_assert (lua_State *L) {
   if (lua_toboolean(L, 1))  /* condition is true? */
     return lua_gettop(L);  /* return all arguments */
   else {  /* error */
-    if (lua_isnone(L, 2))  /* no error message? */
-      lua_pushliteral(L, "assertion failed!");  /* use standard message */
-    lua_remove(L, 1);  /* remove the condition (if there is one...) */
+    luaL_checkany(L, 1);  /* there must be a condition */
+    lua_remove(L, 1);  /* remove it */
+    lua_pushliteral(L, "assertion failed!");  /* default message */
+    lua_settop(L, 1);  /* leave only message (default if no other one) */
     return luaB_error(L);  /* call 'error' */
   }
 }