Function GetLuaTraceback

engine/script/src/script.cpp:351–393

From https://zeux.io/2010/11/07/lua-callstack-with-c-debugger/ and also https://github.com/defold/defold/blob/dev/engine/lua/src/lua/ldblib.c#L321

    // and also
    // https://github.com/defold/defold/blob/dev/engine/lua/src/lua/ldblib.c#L321
    void GetLuaTraceback(lua_State* L, const char* infostring, void (*cbk)(lua_State* L, lua_Debug* entry, void* ctx), void* ctx)
    {
        const int LEVELS1 = 12;  // size of the first part of the stack
        const int LEVELS2 = 10;  // size of the second part of the stack

        int firstpart = 1;
        int arg = 0;
        lua_State* L1 = GetLuaThread(L, &arg);

        lua_Debug entry;
        int level = 0;

        if (lua_isnumber(L, arg+2)) {
            level = (int)lua_tointeger(L, arg+2);
            lua_pop(L, 1); // problematic?!
        }
        else {
            level = (L == L1) ? 1 : 0;  // level 0 may be this own function
        }

        if (lua_gettop(L) != arg && !lua_isstring(L, arg+1)) return;  // message is not a string

        while (lua_getstack(L1, level++, &entry))
        {
            if (level > LEVELS1 && firstpart) {
                // no more than `LEVELS2' more levels?
                if (!lua_getstack(L1, level+LEVELS2, &entry)) {
                    level--;  // keep going
                } else {
                    lua_pushliteral(L, "\n\t...");  // too many levels
                    while (lua_getstack(L1, level+LEVELS2, &entry))  // find last levels
                        level++;
                }
                firstpart = 0;
                continue;
            }
            int status = lua_getinfo(L1, infostring, &entry);
            if (!status)
                continue;

            cbk(L1, &entry, ctx);
        }
    }

    // From ldblib.c function db_errorfb()
    uint32_t WriteLuaTracebackEntry(lua_Debug* entry, char* buffer, uint32_t buffer_size)