help() appears to be broken; doesn't display __doc__ for class type when called as help(type)

[christopherthemagnificent]

BPO	13581
Nosy	@amauryfa, @pitrou
Superseder	bpo-1785: "inspect" gets broken by some descriptors

^{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 2011-12-21.09:18:54.799>
created_at = <Date 2011-12-11.18:26:28.407>
labels = ['interpreter-core', 'type-bug', 'docs']
title = "help() appears to be broken; doesn't display __doc__ for class type when called as help(type)"
updated_at = <Date 2011-12-21.09:18:54.797>
user = 'https://bugs.python.org/christopherthemagnificent'

bugs.python.org fields:

activity = <Date 2011-12-21.09:18:54.797>
actor = 'pitrou'
assignee = 'docs@python'
closed = True
closed_date = <Date 2011-12-21.09:18:54.799>
closer = 'pitrou'
components = ['Documentation', 'Interpreter Core']
creation = <Date 2011-12-11.18:26:28.407>
creator = 'christopherthemagnificent'
dependencies = []
files = []
hgrepos = []
issue_num = 13581
keywords = []
message_count = 5.0
messages = ['149234', '149241', '149967', '149971', '149972']
nosy_count = 5.0
nosy_names = ['amaury.forgeotdarc', 'pitrou', 'christopherthemagnificent', 'docs@python', 'python-dev']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = '1785'
type = 'behavior'
url = 'https://bugs.python.org/issue13581'
versions = ['Python 3.2']

[christopherthemagnificent]

observe help(type) and type.__doc__ in Python 3.1:

>>> help(type)
Help on class type in module builtins:

class type(object)
 |  type(object) -> the object's type
 |  type(name, bases, dict) -> a new type
 |  
 |  Methods defined here:
 |  
 |  __call__(...)
 |      x.__call__(...) <==> x(...)
 |  
 |  __delattr__(...)
 |      x.__delattr__('name') <==> del x.name
 |  
 |  __getattribute__(...)
 |      x.__getattribute__('name') <==> x.name
 |  
 |  __init__(...)
 |      x.__init__(...) initializes x; see x.__class__.__doc__ for signature
 |  
 |  __instancecheck__(...)
 |      __instancecheck__() -> check if an object is an instance
 |  
 |  __repr__(...)
 |      x.__repr__() <==> repr(x)
 |  
 |  __setattr__(...)
 |      x.__setattr__('name', value) <==> x.name = value
 |  
 |  __subclasscheck__(...)
 |      __subclasschck__ -> check if an class is a subclass
 |  
 |  __subclasses__(...)
 |      __subclasses__() -> list of immediate subclasses
 |  
 |  mro(...)
 |      mro() -> list
 |      return a type's method resolution order
 |  
 |  

---

| Data descriptors defined here:
|
| __abstractmethods__
|
| __base__
|
| __bases__
|
| __basicsize__
|
| __dict__
|
| __dictoffset__
|
| __flags__
|
| __itemsize__
|
| __mro__
|
| __weakrefoffset__
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
| __new__ = <built-in method __new__ of type object at 0x145600>
| T.__new__(S, ...) -> a new object with type S, a subtype of T
|
| __prepare__ = <built-in method __prepare__ of type object at 0x145600>
| __prepare__() -> dict
| used to create the namespace for the class statement

>>> type.__doc__
"type(object) -> the object's type\ntype(name, bases, dict) -> a new type"
>>> 

observe help(type) and type.__doc__ in Python 3.2:

>>> help(type)
Help on class type in module builtins:

type = <class 'type'>
>>> type.__doc__
"type(object) -> the object's type\ntype(name, bases, dict) -> a new type"
>>> 

It appears that the __doc__ attribute of <class 'type'> is unchanged from Python 3.1 to 3.2, but it is not being displayed by the help function in Python 3.2.

The help function is very important to using Python! This should be fixed.

[amauryfa]

It fails for the same reason as bpo-1785:

~/python/cpython3.2$ ./python -c "import inspect; inspect.classify_class_attrs(type)"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/home/amauryfa/python/cpython3.2/Lib/inspect.py", line 321, in classify_class_attrs
    obj_via_getattr = getattr(cls, name)
AttributeError: __abstractmethods__

[python-dev]

New changeset 902f694a7b0e by Antoine Pitrou in branch '3.2':
Issue bpo-1785: Fix inspect and pydoc with misbehaving descriptors.
http://hg.python.org/cpython/rev/902f694a7b0e

New changeset b08bf8df8eec by Antoine Pitrou in branch 'default':
Issue bpo-1785: Fix inspect and pydoc with misbehaving descriptors.
http://hg.python.org/cpython/rev/b08bf8df8eec

[python-dev]

New changeset 13f56cd8dec1 by Antoine Pitrou in branch '2.7':
Issue bpo-1785: Fix inspect and pydoc with misbehaving descriptors.
http://hg.python.org/cpython/rev/13f56cd8dec1

[pitrou]

Now fixed in all 3 branches.