We have fairly recently decided that a NULL Host pointer obtained by a function in TLuaInterpreter class should throw a Lua error like this:

Host* pHost = TLuaInterpreter::luaInterpreterMap[L];
if (!pHost) {
    lua_pushstring(L, "functionName: NULL Host pointer - something is wrong!");
    return lua_error(L);
}

however we still have quite a few that still have the previous response:

Host* pHost = TLuaInterpreter::luaInterpreterMap[L];
if (!pHost) {
    lua_pushnil(L);
    lua_pushstring(L, "functionName: NULL Host pointer - something is wrong!");
    return lua_error(L);
}

which need to be revised. Note that this does rely on the need for this check - which is mentioned in the related #947 ; should the check NOT be required than this issue is moot as the code would then be due for removal in either form...!