typing classes do not have __name__ attributes in 3.7+

[gpshead]

BPO	42329
Nosy	@gvanrossum, @gpshead, @serhiy-storchaka, @ilevkivskyi

^{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 = None
closed_at = <Date 2020-11-12.18:48:18.239>
created_at = <Date 2020-11-12.02:23:03.931>
labels = ['type-bug', '3.8', '3.9', '3.10', '3.7', 'library']
title = 'typing classes do not have __name__ attributes in 3.7+'
updated_at = <Date 2020-11-12.18:48:18.238>
user = 'https://github.com/gpshead'

bugs.python.org fields:

activity = <Date 2020-11-12.18:48:18.238>
actor = 'gregory.p.smith'
assignee = 'none'
closed = True
closed_date = <Date 2020-11-12.18:48:18.239>
closer = 'gregory.p.smith'
components = ['Library (Lib)']
creation = <Date 2020-11-12.02:23:03.931>
creator = 'gregory.p.smith'
dependencies = []
files = []
hgrepos = []
issue_num = 42329
keywords = []
message_count = 5.0
messages = ['380801', '380804', '380807', '380830', '380841']
nosy_count = 4.0
nosy_names = ['gvanrossum', 'gregory.p.smith', 'serhiy.storchaka', 'levkivskyi']
pr_nums = []
priority = 'normal'
resolution = 'rejected'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue42329'
versions = ['Python 3.7', 'Python 3.8', 'Python 3.9', 'Python 3.10']

[gpshead]

Python 3.7-3.10a1:

>>> List.__name__
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.8/typing.py", line 760, in __getattr__
    raise AttributeError(attr)
AttributeError: __name__
>>> type(List)
<class 'typing._SpecialGenericAlias'>
>>> type(List[int])
<class 'typing._GenericAlias'>

Python 3.6:

>>> from typing import List
>>> List.__name__
'List'
>>> type(List)
<class 'typing.GenericMeta'>
>>> type(List[int])
<class 'typing.GenericMeta'>

Is this lack of common meta attributes intentional? It makes the typing types unusual.

We just saw it trip up some code that was expecting everything to have a __name__ attribute while moving beyond 3.6. Judging by that __getattr__ implementation it should happen on other common __ attributes as mentioned in https://docs.python.org/3/library/stdtypes.html?highlight=__name__#special-attributes as well.

[gvanrossum]

Between 3.6 and 3.7 they stopped being types.

IIRC this enabled optimizations. (Serhiy?)

I don't think this is important, but I suppose you have some code that this breaks?

The name is passed to the constructor of _SpecialGenericAlias, so I'm fine with fixing this, though the backports may get tricky when you get down to 3.7.

[gpshead]

Not a big deal if we don't, I just found it odd so I figured I'd pose the
question. That it's been in three releases and only just now come up is
pretty telling that isn't critical.

The code in question was trying to identify public functions in a module by
inspecting names and I think they've got a more pedantic way to do that
than their existing code that wouldn't be tripped up by a mere callable
without a __name__.

On Wed, Nov 11, 2020, 8:47 PM Guido van Rossum <report@bugs.python.org>
wrote:

Guido van Rossum <guido@python.org> added the comment:

Between 3.6 and 3.7 they stopped being types.

IIRC this enabled optimizations. (Serhiy?)

I don't think this is important, but I suppose you have some code that
this breaks?

The name is passed to the constructor of _SpecialGenericAlias, so I'm fine
with fixing this, though the backports may get tricky when you get down to
3.7.

----------
nosy: +serhiy.storchaka

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