[ python-Bugs-1367183 ] inspect.getdoc fails on objs that use property for __doc__

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Bugs item #1367183, was opened at 2005-11-26 21:42
Message generated for change (Comment added) made by gbrandl
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Category: Python Library
Group: Python 2.4
>Status: Closed
>Resolution: Wont Fix
Priority: 5
Submitted By: Drew Perttula (drewp)
Assigned to: Nobody/Anonymous (nobody)
Summary: inspect.getdoc fails on objs that use property for __doc__

Initial Comment:
inspect.getdoc has these lines:

     if not isinstance(doc, types.StringTypes):
         return None

which interfere with the case where __doc__ is some
other thing that has a good __str__. I wanted to make a
lazy __doc__ that did an expensive lookup of some
external documentation only when it was str()'d, but
since doc displayers often (correctly) use
inspect.getdoc, they were getting None.

I think the intention of the test in getdoc() is to
avoid trying string operations on a __doc__ that is
None. I think that a more lenient version would allow
me to do my fancy docstrings but still solve the
'__doc__ is None' problem. Please consider the
following patch:

if doc is None:
     return None
doc = str(doc)



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>Comment By: Georg Brandl (gbrandl)
Date: 2006-04-12 15:19

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Closing as Won't Fix.

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Comment By: Neal Norwitz (nnorwitz)
Date: 2006-03-20 08:04

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That code doesn't work if doc is unicode.  I'm not sure how
to achieve what you want.

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Comment By: Georg Brandl (birkenfeld)
Date: 2006-02-20 08:21

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I don't know. Neal, do you have an opinion about property
docstrings?

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Comment By: Collin Winter (collinwinter)
Date: 2006-02-01 11:35

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It's not a good idea to use properties for __doc__:

"""
>>> class Foo(object):
...    def _get(self):
...        return 'the docstring'
...    __doc__ = property(_get)
...
>>> print Foo().__doc__
the docstring
>>> print Foo.__doc__
<property object at 0xb7b3a234>
>>>
"""

In this light, I don't view inspect.getdoc's lack of support
for __doc__-as-property as a bug.

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