Binding LuaJIT to C++ with LuaBridge results in "PANIC: unprotected error" - c++

Question

Windows 10 x64, MSVC 2017, LuaJIT 2.0.5.
I searched the web, but answers didn't help.
Basically I'm trying to follow this manual, except that I had to place #include <LuaBridge.h> after Lua includes, because otherwise it doesn't work saying that the LuaBridge should go after Lua includes.
Hovewher, I get following error: PANIC: unprotected error in call to Lua API (attempt to call a nil value).
I have no idea why. If you need more info - just say what.
#include "stdafx.h"
#include <iostream>
#include <lua.hpp>
#include <LuaBridge/LuaBridge.h>
using namespace luabridge;
using namespace std;
int main()
{
lua_State* L = luaL_newstate();
luaL_dofile(L, "script.lua");
luaL_openlibs(L);
lua_pcall(L, 0, 0, 0);
LuaRef s = getGlobal(L, "testString");
LuaRef n = getGlobal(L, "number");
string luaString = s.cast<string>();
int answer = n.cast<int>();
cout << luaString << endl;
cout << "And here's our number:" << answer << endl;
system("pause");
return 0;
}
script.lua:
testString = "LuaBridge works!"
number = 42

Answer 1

The code in the tutorial is faulty. lua_pcall has nothing to call because luaL_dofile and luaL_openlibs don't push a function onto the stack, so it tries to call nil and returns 2 (the value of the macro LUA_ERRRUN).
I verified this by changing the code from the tutorial thus and compiling with g++. I didn't get a PANIC error, for whatever reason; maybe because it was using Lua 5.3:
#include <iostream>
extern "C" {
# include "lua.h"
# include "lauxlib.h"
# include "lualib.h"
}
#include <LuaBridge/LuaBridge.h>
using namespace luabridge;
int main() {
lua_State* L = luaL_newstate();
luaL_dofile(L, "script.lua");
std::cout << "type of value at top of stack: " << luaL_typename(L, -1) << std::endl;
luaL_openlibs(L);
std::cout << "type of value at top of stack: " << luaL_typename(L, -1) << std::endl;
std::cout << "result of pcall: " << lua_pcall(L, 0, 0, 0) << std::endl; // Print return value of lua_pcall. This prints 2.
LuaRef s = getGlobal(L, "testString");
LuaRef n = getGlobal(L, "number");
std::string luaString = s.cast<std::string>();
int answer = n.cast<int>();
std::cout << luaString << std::endl;
std::cout << "And here's our number: " << answer << std::endl;
}
As you noticed, the code is also faulty because the Lua headers have to be included before the LuaBridge header!