[luatex] Problem with node.has_attribute

[Stéphane Goujet]

Hello,

   In my opinion, node.has_attribute behaves wrongly when the attribute 
number passed as parameter is nil. Since the attribute number is 
incorrect, it should return nil; but it returns a valid result.

   This is the current code in lnodelib.c :
====================
static int lua_nodelib_has_attribute(lua_State * L)
{
     halfword *n;
     int i, val;
     n = check_isnode(L, 1);
     if (n != NULL) {
         i = (int) lua_tointeger(L, 2);
         val = (int) luaL_optinteger(L, 3, UNUSED_ATTRIBUTE);
         if ((val = has_attribute(*n, i, val)) > UNUSED_ATTRIBUTE) {
             lua_pushnumber(L, val);
             return 1;
         }
     }
     lua_pushnil(L);
     return 1;
}
=====================

   lua_tointeger() may return anything if the parameter is not an integer. 
So a check should be added before calling lua_tointeger(). I am not sure 
if the exact integer correctness should be tested, but I think it should 
be at least tested against nil.


Goodbye,
   Stéphane Goujet.