[Python-Dev] python 3.0, tp_compare not used for == test?

[Campbell Barton]

Hi, I have been writing a new C api that can build with both python 2.6 and 3.0

I found that when building with python 2.6, doing "a==b" between 2
different pyrna_struct_Type's would run tp_compare

But with python 3.0, "a==b" will always be false and tp_compare
function would not even run.
The only way to get it to run the tp_compare function was to do
"cmp(a, b)" however Id like to be able to use == still.

The only way I could get "a==b" to work in python 3.0 was to add a
tp_richcompare function which runs tp_compare with Py_CmpToRich()
anyway

Is this the intended behavior? - if so its important for external C
API's to be updated to support this.

Included the PyType below with some relevant details. I looked at
other Python 3.0 types but could not see why this would happen.


// ----snip,
//  initialized with PyType_Ready

	if( PyType_Ready( &pyrna_struct_Type ) < 0 )
		return NULL;

// header definition for BPy_StructRNA

typedef struct {
	PyObject_HEAD /* required python macro   */
	PointerRNA ptr;
	int freeptr; /* needed in some cases if ptr.data is created on the
fly, free when deallocing */
} BPy_StructRNA;

// PyType

/*-----------------------BPy_StructRNA method
def------------------------------*/
PyTypeObject pyrna_struct_Type = {
	PyVarObject_HEAD_INIT(NULL, 0)
	"StructRNA",			/* tp_name */
	sizeof( BPy_StructRNA ),	/* tp_basicsize */
	0,			/* tp_itemsize */
	/* methods */
	( destructor ) pyrna_struct_dealloc,/* tp_dealloc */
	NULL,                       /* printfunc tp_print; */
	NULL,						/* getattrfunc tp_getattr; */
	NULL,						/* setattrfunc tp_setattr; */
	( cmpfunc ) pyrna_struct_compare,	/* tp_compare */
	( reprfunc ) pyrna_struct_repr,	/* tp_repr */

	/* Method suites for standard classes */

	NULL,                       /* PyNumberMethods *tp_as_number; */
	NULL,						/* PySequenceMethods *tp_as_sequence; */
	NULL,						/* PyMappingMethods *tp_as_mapping; */

	/* More standard operations (here for binary compatibility) */

	( hashfunc )pyrna_struct_hash,	/* hashfunc tp_hash; */
	NULL,						/* ternaryfunc tp_call; */
	NULL,                       /* reprfunc tp_str; */
	( getattrofunc ) pyrna_struct_getattro,	/* getattrofunc tp_getattro; */
	( setattrofunc ) pyrna_struct_setattro,	/* setattrofunc tp_setattro; */

	/* Functions to access object as input/output buffer */
	NULL,                       /* PyBufferProcs *tp_as_buffer; */

  /*** Flags to define presence of optional/expanded features ***/
	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,         /* long tp_flags; */

	NULL,						/*  char *tp_doc;  Documentation string */
  /*** Assigned meaning in release 2.0 ***/
	/* call function for all accessible objects */
	NULL,                       /* traverseproc tp_traverse; */

	/* delete references to contained objects */
	NULL,                       /* inquiry tp_clear; */

  /***  Assigned meaning in release 2.1 ***/
  /*** rich comparisons ***/
	(richcmpfunc)pyrna_struct_richcmp,	/* richcmpfunc tp_richcompare; */

  /***  weak reference enabler ***/
	0,                          /* long tp_weaklistoffset; */

  /*** Added in release 2.2 ***/
	/*   Iterators */
	NULL,                       /* getiterfunc tp_iter; */
	NULL,                       /* iternextfunc tp_iternext; */

  /*** Attribute descriptor and subclassing stuff ***/
	pyrna_struct_methods,		/* struct PyMethodDef *tp_methods; */
	NULL,                       /* struct PyMemberDef *tp_members; */
	NULL,      					/* struct PyGetSetDef *tp_getset; */
	NULL,                       /* struct _typeobject *tp_base; */
	NULL,                       /* PyObject *tp_dict; */
	NULL,                       /* descrgetfunc tp_descr_get; */
	NULL,                       /* descrsetfunc tp_descr_set; */
	0,                          /* long tp_dictoffset; */
	NULL,                       /* initproc tp_init; */
	NULL,                       /* allocfunc tp_alloc; */
	pyrna_struct_new,			/* newfunc tp_new; */
	/*  Low-level free-memory routine */
	NULL,                       /* freefunc tp_free;  */
	/* For PyObject_IS_GC */
	NULL,                       /* inquiry tp_is_gc;  */
	NULL,                       /* PyObject *tp_bases; */
	/* method resolution order */
	NULL,                       /* PyObject *tp_mro;  */
	NULL,                       /* PyObject *tp_cache; */
	NULL,                       /* PyObject *tp_subclasses; */
	NULL,                       /* PyObject *tp_weaklist; */
	NULL
};



-- 
- Campbell