Nested class __name__

[gvanrossum]

BPO	633930
Nosy	@gvanrossum, @birkenfeld

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/gvanrossum'
closed_at = <Date 2012-07-29.19:01:53.589>
created_at = <Date 2002-11-05.17:56:34.000>
labels = ['interpreter-core']
title = 'Nested class __name__'
updated_at = <Date 2012-07-29.19:01:53.589>
user = 'https://github.com/gvanrossum'

bugs.python.org fields:

activity = <Date 2012-07-29.19:01:53.589>
actor = 'mstefanro'
assignee = 'gvanrossum'
closed = True
closed_date = None
closer = None
components = ['Interpreter Core']
creation = <Date 2002-11-05.17:56:34.000>
creator = 'gvanrossum'
dependencies = []
files = []
hgrepos = []
issue_num = 633930
keywords = []
message_count = 7.0
messages = ['13078', '13079', '13080', '13081', '13082', '166775', '166802']
nosy_count = 4.0
nosy_names = ['gvanrossum', 'georg.brandl', 'xiaq', 'mstefanro']
pr_nums = []
priority = 'low'
resolution = None
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue633930'
versions = ['Python 2.6', 'Python 2.7']

[gvanrossum]

The __name__ attribute of a nested class should be set
to 'outer.inner', both for classic and for new-style
classes. E.g.

>>> class C:
...     class C1: pass
... 
>>> C.C1.__name__
'C.C1'
>>>

[gvanrossum]

Logged In: YES
user_id=6380

Hm, but should this also be done for functions inside
classes? E.g.

class C:
 def foo(self): pass

assert C.foo.__name__ == "C.foo"
assert C.__dict__["foo"].__name__ == "C.foo"

And what about classes inside functions?

def f():
  class C: pass
  return C

assert f().__name__ == "f.C"

???

[gvanrossum]

Logged In: YES
user_id=6380

I'm less sure I even want this now, and not at all sure how
to do it any more, so lowering priority.

[birkenfeld]

Any interest for Python 3000 on this? Otherwise we can close it.

[gvanrossum]

I don't think so. Closing.

[xiaq]

There is a bigger problem:

>>> class C:
...     class D:
...         pass
...
>>> repr(C)
"<class '__main__.C'>"
>>> repr(C.D)
"<class '__main__.D'>"

Default repr on nested classes produce specious results.

The problem become pratical when you have two nested classes C1.D and C2.D in module m, which end up being both "m.D" in exception traceback.

Classes nested in function are likely to contain some information from the function arguments and are thus different on each function call, making it impossible to have a general way to name them. Thus I propose embedding the resulting class's id in name, like what i'm doing manually in a hulking way:

>>> def factory(foo):
...     class C(object):
...         bar = foo
...     func_name = 'factory'
...     C.__name__ = '%s generated classobj at 0x%x' % (func_name, id(C))
...     return C
...
>>> factory(0)
<class '__main__.factory generated classobj at 0x32273c0'>
>>> factory(0)
<class '__main__.factory generated classobj at 0x32245b0'>

Please consider reopening this issue.

[mstefanro]

Only an issue in Python2.

    >>> A.B.__qualname__
    'A.B'
    >>> repr(A.B)
    "<class '__main__.A.B'>"