[Python-3000] Get rid of Py_FindMethod

Guido van Rossum guido at python.org
Tue Jul 1 19:06:49 CEST 2008

On Tue, Jul 1, 2008 at 5:37 AM, Amaury Forgeot d'Arc <amauryfa at gmail.com> wrote:
> http://bugs.python.org/issue3247 complains that with python 3.0, dir()
> of a SRE_Match object returns an empty list.
> This type has the particularity to not define a tp_methods; instead,
> its tp_getattr slot calls Py_FindMethod(match_methods, self, name)
> where "match_methods" is a PyMethodDef[] array that looks very very
> similar to a typical tp_methods slot.
> Py_FindMethod has a trick: when the requested name is "__methods__",
> it returns the names of the PyMethodDef items.
> __methods__ has disappeared with python 3.0, and indeed if I enable
> the "-3" warning flag on python2.6,
> dir() on a SRE_Match object raises two (!) warnings:
> __main__:1: DeprecationWarning: __methods__ not supported in 3.x
> __main__:1: DeprecationWarning: __members__ and __methods__ not supported in 3.x
> According to previous discussions:
> http://mail.python.org/pipermail/python-3000/2007-July/008787.html
> Py_FindMethod is not needed any more in modern modules, and should go away.
> Note that PyMember_Get has already disappeared, because the few
> modules using them were deleted...
> Is it still time for such a change after beta1?

I'd say definitely. This just fell through the cracks.

> There are ~30 occurrences of Py_FindMethod in the code base.
> Most of the time, it is enough to remove the call, and set the
> tp_methods members.


> Another thing: why was traceback.__dir__ added?
> the current 3.0 produces:
>>>> dir(b.__traceback__)
> ['tb_frame', 'tb_lasti', 'tb_lineno', 'tb_next']
> When I remove the __dir__ method, I get the special methods as well:
>>>> dir(b.__traceback__)
> ['__class__', '__delattr__', '__doc__', '__eq__', '__format__',
> '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__',
> '__le__', '__lt__', '__ne__', '__new__', '__reduce__',
> '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__',
> '__subclasshook__', 'tb_frame', 'tb_lasti', 'tb_lineno', 'tb_next']
> It's more verbose, but most types have the same list of special
> members. I suggest to remove it, to enhance consistency (loosing some
> 2.6 compatibility, but it's python3.0 after all)

Can't tell you why -- looks odd to me too. Hopefully Collin Winter remembers.

--Guido van Rossum (home page: http://www.python.org/~guido/)

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