bug report

[roberto@... (Roberto Ierusalimschy)]

what: debug hooks may get wrong when mixed with coroutines

report: by Ivko Stanilov, 03/06/2006

example:

-- crashes Lua (by Ivko Stanilov)
function foo (a)
        return coroutine.yield(2*a)
end

co = coroutine.create(function (a,b)
   local r = foo(a+1)
   local r, s = coroutine.yield(a+b, a-b)
   return b, "end"
end)

debug.sethook(co, function() end, "lcr")
coroutine.resume(co, 100, 2000)
coroutine.resume(co, 100, 2000)


patch:

* ldo.c:
@@ -389,6 +389,7 @@
       return;
   }
   else {  /* resuming from previous yield */
+    L->status = 0;
     if (!f_isLua(ci)) {  /* `common' yield? */
       /* finish interrupted execution of `OP_CALL' */
       lua_assert(GET_OPCODE(*((ci-1)->savedpc - 1)) == OP_CALL ||
@@ -399,7 +400,6 @@
     else  /* yielded inside a hook: just continue its execution */
       L->base = L->ci->base;
   }
-  L->status = 0;
   luaV_execute(L, cast_int(L->ci - L->base_ci));
 }


(This bug will be corrected in Lua 5.1.1.)

-- Roberto