[Python-Dev] Garbage collector problem

[Tim Peters]

[Tim]
> ...
> The mystery to me now is why the a,b,c,d,e loop didn't happen in 2.2.1.

Because 2.2.1 has a bug in PyCFunction_New(), which ends with

	op->m_self = self;
	PyObject_GC_Init(op);
	return (PyObject *)op;

But also in 2.2.1,

/* This is here for the sake of backwards compatibility.  Extensions that
 * use the old GC API will still compile but the objects will not be
 * tracked by the GC. */
#define PyGC_HEAD_SIZE 0
#define PyObject_GC_Init(op)
#define PyObject_GC_Fini(op)
#define PyObject_AS_GC(op) (op)
#define PyObject_FROM_GC(op) (op)

IOW, PyObject_GC_Init(op) is a nop in 2.2.1, and the bound method object
never gets tracked.  Therefore the a,b,c,d,e loop never gets started.

In current CVS, the function ends with

	op->m_self = self;
	_PyObject_GC_TRACK(op);
	return (PyObject *)op;

and a world of fun follows <wink>.