memory leak in session receive on response?

[wmoors]

If I use a closure callback function when creating a request (to keep a reference alive as an upvalue while waiting for the response), I noticed that my program started to leak memory albeit at a very slow pace.

I started to look into this and traced it back to the static int lmpack_session_receive(lua_State *L) function in lmpack.c. It seems that the cookie passed along when creating the request is not being unref'd, so the garbage collector failed to remove the callback function, which in turn kept the upvalue reference alive and so on...

When applying this patch, the leak seems to be fixed for me:

diff --git a/lmpack.c b/lmpack.c
index 4a7e4d1..5ec1a52 100644
--- a/lmpack.c
+++ b/lmpack.c
@@ -904,6 +904,8 @@ static int lmpack_session_receive(lua_State *L)
     case MPACK_RPC_RESPONSE:
       lua_pushstring(L, "response");
       lmpack_geti(L, session->reg, (int)session->unpacked.msg.data.i);
+      lmpack_unref(L, session->reg, (int)session->unpacked.msg.data.i);
+      session->unpacked.msg.data.i = LUA_NOREF;
       break;
     case MPACK_RPC_NOTIFICATION:
       lua_pushstring(L, "notification");

I am not completely convinced this is the right way to fix it, so I didn't submit a patch and post an issue instead.

[Bartel-C8]

May be closed now, thanks!