Re[2]: LuaJIT + Coco : coroutine issue

[Dmitriy Iassenev <iassenev@...>]

Hello Mike,

>> But all is ok only in case when newly created thread is in the lua
>> stack, though I use luaL_ref for referencing thread to prevent it to
>> be garbage collected and to remove it form the lua stack. This scheme
>> works fine for Lua 5.1 alpha, but it doesn work with LuaJIT + Coco.
MP> Well, but what happens? An error or a crash?
access violation on lua_resume call, because lua_state, associated with
the thread, is invalid. using debug memory allocator (which fills freed
data with 'C'), I found, that lua_State, returned by lua_newcthread,
is just freed during garbage collection, i.e. thread is collected

MP> * You get the above error: This must be a logic error somewhere.
MP> You are resuming the wrong coroutine or a coroutine not created
MP> with lua_newcthread. You may never notice this with plain Lua.
it is happened only after 86th update of the thread :). and it seems
to me thread is simply collected. thread function looks like this

while true do
      foo()
      coroutine.yield()
end

MP> * A crash when running under Windows XP: Please apply this change:
MP>   http://lua-users.org/lists/lua-l/2005-12/msg00098.html
I use Windows XP, but I applied your patch before

MP> * Still a crash in a random place: Are you 100% sure you've made a
MP> reference to the coroutine? The incremental garbage collection is
MP> very sensitive to tiny changes and LuaJIT obviously allocates a
MP> few more objects.
code looks like this:
     on thread construction
                m_state                = lua_newcthread(L,0);
                VERIFY2                (m_state,"Cannot create new Lua thread");
                m_thread_reference     = luaL_ref(L,LUA_REGISTRYINDEX);

     when thread is finished or we should exit
                luaL_unref             (L,LUA_REGISTRYINDEX,m_thread_reference);

I can even comment luaL_unref call, but it changes nothing - thread is
collected

MP> I suggest you turn on assertions as described in
MP>   jitdoc/luajit_debug.html
no assertion accured during the tests I did

MP> and then check if you get strange errors. This almost always
MP> means a coroutine reference has been lost.
I am sure I have troubles because of the reference, since if I leave
thread in the lua stack all works fine. I used references before in
Lua 5.02 and all worked correct.

-- 
Best regards,
 Dmitriy                            mailto:iassenev@gsc-game.kiev.ua