help(), when used on an enum member or class, returns almost nothing. I suspect the custom __dir__ is at fault, but whatever is causing the problem needs fixing.

With custom __dir__:

Help on class Enum in module enum:

Enum = <enum 'Enum'>

----------------------------------------------------

Without custom __dir__:

Help on class Enum in module enum:

class Enum(builtins.object)
 |  Generic enumeration.
 |  
 |  Derive from this class to define new enumerations.
 |  
 |  Methods defined here:
 |  
 |  __eq__(self, other)
 |  
 |  __getnewargs__(self)
 |  
 |  __hash__(self)
 |  
 |  __repr__(self)
 |  
 |  __str__(self)
 |  
 |  

| Static methods defined here:
|
| __new__(cls, value)
|
| ----------------------------------------------------------------------
| Data descriptors defined here:
|
| __dict__
| dictionary for instance variables (if defined)
|
| __weakref__
| list of weak references to the object (if defined)
|
| name
| Route attribute access on a class to __getattr__.
|
| This is a descriptor, used to define attributes that act differently when
| accessed through an instance and through a class. Instance access remains
| normal, but access to an attribute through a class will be routed to the
| class's __getattr__ method; this is done by raising AttributeError.
|
| value
| Route attribute access on a class to __getattr__.
|
| This is a descriptor, used to define attributes that act differently when
| accessed through an instance and through a class. Instance access remains
| normal, but access to an attribute through a class will be routed to the
| class's __getattr__ method; this is done by raising AttributeError.

---------------------------------------------------------------

I'm thinking we should drop the custom __dir__. help() is far more important than not seeing some things with dir().

New changeset 5d417257748e by Ethan Furman in branch 'default':
Close bpo-18693: __dir__ removed from Enum; help() now helpful.
http://hg.python.org/cpython/rev/5d417257748e

Less than two days passed since this issue was opened. No waiting for feedback? No patch? No code review?

Maybe there's another solution? Personally I find dir() often more useful than help(). Maybe help() can be adapted to behave nicely for classes with custom __dir__ and it could be useful elsewhere?

Is this such a burning immediate need that we forego all the usual discussion channels?

Sorry, sorry.

Long week, felt like more than two days, mild sense of unease and stress due to non-functioning Release Schedule on python.org, and wanting to get Enum used /somewhere/ in the stdlib before 3.4 is locked down.

Making help() better would be a better solution, especially if we enhanced it to show docstrings on instances.

I'll see what I can figure out. Feel free to beat me to it. :)

Ethan, http://www.python.org/dev/peps/pep-0429/#release-schedule
TL;DR - no new features after beta 1 (2013-11-24), no non-release-critical bug fixes after rc1 (2014-01-19)

Ethan, as Ned said (and I think you got this answer in the list before), the real feature cutoff is Beta 1. So we have time until the end of November. Note that even new PEPs (like the statistics one) can go in before that. Even after beta, things that appear to be bugs (like this issue) can usually be fixed before the RCs come. So there is no time pressure whatsoever.

So what do we want Enum's __dir__ to report?

Normally we see things like __eq__, __dict__, __getnewargs__, etc.

For IntEnum there would be __abs__, __floor__, __div__, etc.

Do we want to worry about those kinds of differences? I think we do.

And if we do, then we are looking at removing items to make our custom __dir__, and with each release we would have to revisit the blacklist of items we don't want (the tests would catch that for us, but it would still be effort to update the code).

What if we took what object.__dir__ gave us, then added the Enum members while removing the private, er, non-public data structures?

In other words, this dir in EnumMeta:

    def __dir__(cls):
        items = set(super().__dir__())
        disgard = set([m for m in items if _is_sunder(m)])
        members = set(cls.__members__)
        return sorted((items | members) ^ disgard)

with this Enum:

>>> class Color(enum.Enum):
...  RED = 1
...  BLUE = 2
...  GREEN = 3
... 

gives us this result:

>>> dir(Color)
['BLUE', 'GREEN', 'RED', '__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getnewargs__', '__gt__', '__hash__', '__init__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'name', 'value']

Huh. I just checked help(Color) on my proposed dir and got the two-line, rather useless, response. Perhaps help() is broken with all custom __dir__s.

Ethan, please revert your commit first. I liked the previous dir. The current one is useless.

I think you may be right about help, but I didn't dig deep enough to be sure.

New changeset 39697dcd97e3 by Ethan Furman in branch 'default':
bpo-18693: Put custom dir back in place. Will instead look at fixing help().
http://hg.python.org/cpython/rev/39697dcd97e3

Do we have enough evidence to open a new bug vs. help() ?

I've done some more investigation today but I can't tell if the issue is solely in help or if it's some wierd
interaction between help and _EnumMeta.

On Sun, Sep 1, 2013 at 5:29 PM, Ethan Furman <report@bugs.python.org> wrote:

Ethan Furman added the comment:

I've done some more investigation today but I can't tell if the issue is
solely in help or if it's some wierd
interaction between help and _EnumMeta.

So you can't reproduce it with other classes that have a custom __dir__ ?

Nope, not yet. And even a simple dummy metaclass with a custom __dir__ worked fine.

What I know for sure:

1. if something is added to dir() that does not live in __dict__, help() breaks.

2. if a certain something or some things are removed from dir(), help() breaks. I'm not yet certain which somethings
   apply here.

That help() is confused by __dir__ is documented in bpo-16938.

AFAIK help is fairly fragile in its expectations of the attributes present on classes and the correspondence between dir(cls) and list(cls.__dict__), and that is something that could be fixed in pydoc and/or inspect.

Found it!

It was a combination of __objclass__ not being defined on the enum mmebers, and the metatype not being searched in the __mro__ by inspect. Thanks, Ronald, for the necessary clues.

Patch attached.

I'm not sure if I have the method wowser showing up in the correct dir(). Thoughts?

Great, Ethan.

I'd say the inspect fix has to be reviewed and committed separately. Maybe bpo-16938 is the right place to post the patch for it. Once that's in, we can review/commit the enum parts.

help() won't really be fixed with the inspect patch. If no objections within a few hours I'll open a new issue for it.

Okay, here's the patch after the inspect portion was committed in bpo-18929.

Summary:

• added __objclass__ to each enum member
• added __module__ to the class dir
• aded any extra methods defined to the instance dir
• changed _RouteClassAttributeToGetattr to use the wrapped doc if it exists
• added more useful __doc__s to value and name
• added another test :)

Two issues still remain:

• custom behavior, as well as value and name, don't show in help
• value and name, if defined as enum members, show up as data
  descriptors in help

=======================================================================================
--> class Test(enum.Enum):
... this = 'that'
... these = 'those'
... whose = 'mine'
... name = 'Python'
... value = 'awesome'
... def what(self):
... return "%s is %s!" % (self.name, self.value)
...

--> dir(Test)
['__class__', '__doc__', '__members__', '__module__', 'name', 'these', 'this', 'value', 'whose']

--> dir(Test.this)
['__class__', '__doc__', '__module__', 'name', 'value', 'what']

--> help(Test)
Help on Test in module __main__ object:

class Test(enum.Enum)
 |  Method resolution order:
 |      Test
 |      enum.Enum
 |      builtins.object
 |  
 |  Data and other attributes defined here:
 |  
 |  these = <Test.these: 'those'>
 |  
 |  this = <Test.this: 'that'>
 |  
 |  whose = <Test.whose: 'mine'>
 |  
 |  

| Data descriptors inherited from enum.Enum:
|
| name
| The name of the Enum member.
|
| value
| The value of the Enum member.
|
| ----------------------------------------------------------------------
| Data descriptors inherited from enum.EnumMeta:
|
| __members__
| Returns a mapping of member name->value.
|
| This mapping lists all enum members, including aliases. Note that this
| is a read-only view of the internal mapping.
(END)
=======================================================================================

At this point, dir() on an Enum member shows what can be done with the member, and dir() on an Enum class shows what can be done with the class.

I'll create new issues to track changes for inspect and help.

New changeset 353ced6ae182 by Ethan Furman in branch 'default':
Close bpo-18693: Enum is now more help() friendly.
http://hg.python.org/cpython/rev/353ced6ae182

Tracking inspect in bpo-19030.

Tracking help in bpo-19031.