Re: super bad

I'm not sure if it is related, but try applying the attached git patch.

It fixed our valgrind woes.

-Evan


Nigel Atkinson wrote:
> Hello list!
> 
> I had a bug in an app I'm writing, and while it was my goof i.e. you
> shouldn't really rely on the order of objects being garbage collected, I
> thought I'd share a debugging post mortem.  I'm using 0.9.0 but it may
> apply to 0.8.1 and possibly 0.7 
> 
> So I found that last created instance of a Lua class that has a base
> class, stayed around until lua_close, despite having any reference I
> knew about set to nil.
> 
> In hind sight 'super' seems almost obvious.  Even though it is
> deprecated, it's still there, to tell you its deprecated when you use
> it. 
> 
> It took me awhile to narrow it down to this, as I had shared pointers in
> the mix witch sent me barking up the wrong tree. ;-)
> 
> I just commented out the 'super' code in class_rep.cpp in the 
> 
> int luabind::detail::class_rep::constructor_dispatcher(lua_State* L)
> 
> function.  It's pretty obvious what to zap.  
> 
> Seeing as super is depreciated, this problem will go away eventually.  A
> quick fix I guess would be to set 'super' to nil, after you have created
> a class instance.
> 
> Hope this prevents or reduces some face-palms and keyboard thumping. :-)
> 
> Nigel Atkinson
> 
> 
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commit d306a7783afdb31b6e66ae0d04a3ebd3a1429029
Author: Daniel Wallin <[email protected]>
Date:   Fri Nov 6 20:54:23 2009 +0100

    Allocate storage for instances with object_rep::allocate().

    We would allocate storage using operator new for newly constructed
    instances. The memory would later be released with std::free() when
    the object_rep was destroyed. Additionally, this allows instances to
    be allocated inside the object_rep small buffer.

diff --git a/luabind/detail/constructor.hpp b/luabind/detail/constructor.hpp
index b752cd3..60d97ac 100644
--- a/luabind/detail/constructor.hpp
+++ b/luabind/detail/constructor.hpp
@@ -39,6 +39,8 @@ struct construct
 template <class T, class Pointer, class Signature>
 struct construct_aux<0, T, Pointer, Signature>
 {
+    typedef pointer_holder<Pointer, T> holder_type;
+
     void operator()(argument const& self_) const
     {
         object_rep* self = touserdata<object_rep>(self_);
@@ -50,7 +52,9 @@ struct construct_aux<0, T, Pointer, Signature>
         void* naked_ptr = instance.get();
         Pointer ptr(instance.release());

-        self->set_instance(new pointer_holder<Pointer, T>(
+        void* storage = self->allocate(sizeof(holder_type));
+
+        self->set_instance(new (storage) holder_type(
             ptr, registered_class<T>::id, naked_ptr, cls));
     }
 };
@@ -81,6 +85,8 @@ struct construct_aux<N, T, Pointer, Signature>
 # define BOOST_PP_LOCAL_LIMITS (1,N)
 # include BOOST_PP_LOCAL_ITERATE()

+    typedef pointer_holder<Pointer, T> holder_type;
+
     void operator()(argument const& self_,
BOOST_PP_ENUM_BINARY_PARAMS(N,a,_)) const
     {
         object_rep* self = touserdata<object_rep>(self_);
@@ -92,7 +98,9 @@ struct construct_aux<N, T, Pointer, Signature>
         void* naked_ptr = instance.get();
         Pointer ptr(instance.release());

-        self->set_instance(new pointer_holder<Pointer, T>(
+        void* storage = self->allocate(sizeof(holder_type));
+
+        self->set_instance(new (storage) holder_type(
             ptr, registered_class<T>::id, naked_ptr, cls));
     }
 };