Re: Possible bug in coroutine.resume?

[Florian Nücke <florian@...>]

> Bug confirmed. I guess the problem is this line when finishing
> 'lua_resume' (file ldo.c):
>
>    L->nny = 1;  /* do not allow yields */
>
> (It assumed to coroutine was not running before the call to resume,
> so it restores its original status; but in your example the original
> status was not "do not allow yields".) But I have to check it.

Indeed. Storing and restoring the previous value works:

```
ldo.c:
@@ -526,9 +526,10 @@ static void resume (lua_State *L, void *ud) {


 LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs) {
-  int status;
+  int status, nny;
   lua_lock(L);
   luai_userstateresume(L, nargs);
+  nny = L->nny;
   L->nCcalls = (from) ? from->nCcalls + 1 : 1;
   L->nny = 0;  /* allow yields */
   api_checknelems(L, (L->status == LUA_OK) ? nargs + 1 : nargs);
@@ -548,7 +549,7 @@ LUA_API int lua_resume (lua_State *L, lua_State 
*from, int nargs) {
     }
     lua_assert(status == L->status);
   }
-  L->nny = 1;  /* do not allow yields */
+  L->nny = nny;  /* restore yield permission */
   L->nCcalls--;
   lua_assert(L->nCcalls == ((from) ? from->nCcalls : 0));
   lua_unlock(L);
```

Unless I'm missing something. At least the basic tests from the test 
suite all still pass.

> -- Roberto

Florian