[ python-Bugs-864944 ] doctest chokes on recursive members

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Bugs item #864944, was opened at 2003-12-23 13:51
Message generated for change (Comment added) made by gintautasm
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Category: Python Library
Group: Python 2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Gintautas Miliauskas (gintautasm)
Assigned to: Nobody/Anonymous (nobody)
Summary: doctest chokes on recursive members

Initial Comment:
doctests recurse infinitely when they find a recursive
member in a class. A simple example:

--b0rk.py--
class Crash:
    pass

Crash.c = Crash
-----

--test.py--
import doctest
import b0rk

doctest.testmod(b0rk)
-----

--output of test.py--
Traceback (most recent call last):
  File "test.py", line 5, in ?
    doctest.testmod(b0rk)
  File "/usr/lib/python2.3/doctest.py", line 1148, in
testmod
    f, t = tester.rundict(m.__dict__, name, m)
  File "/usr/lib/python2.3/doctest.py", line 908, in
rundict
    f2, t2 = self.__runone(value, name + "." + thisname)
  File "/usr/lib/python2.3/doctest.py", line 1069, in
__runone
    return self.rundoc(target, name)
  File "/usr/lib/python2.3/doctest.py", line 828, in rundoc
    f2, t2 = self.run__test__(d, name)
<.............................>
  File "/usr/lib/python2.3/doctest.py", line 935, in
run__test__
    f, t = self.rundoc(v, thisname)
  File "/usr/lib/python2.3/doctest.py", line 790, in rundoc
    for tag, kind, homecls, value in
_classify_class_attrs(object):
  File "/usr/lib/python2.3/inspect.py", line 201, in
classify_class_attrs
    mro = getmro(cls)
RuntimeError: maximum recursion depth exceeded
-----

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>Comment By: Gintautas Miliauskas (gintautasm)
Date: 2003-12-29 12:46

Message:
Logged In: YES 
user_id=936754

I guess I snipped a little too much traceback...

Here is a part of traceback (reproduced with python 2.2.)
that illustrates the idea:

<...>
  File "/usr/lib/python2.2/doctest.py", line 905, in run__test__
    f, t = self.rundoc(v, thisname)
  File "/usr/lib/python2.2/doctest.py", line 798, in rundoc
    f2, t2 = self.run__test__(d, name)
  File "/usr/lib/python2.2/doctest.py", line 905, in run__test__
    f, t = self.rundoc(v, thisname)
  File "/usr/lib/python2.2/doctest.py", line 798, in rundoc
    f2, t2 = self.run__test__(d, name)
  File "/usr/lib/python2.2/doctest.py", line 905, in run__test__
    f, t = self.rundoc(v, thisname)
  File "/usr/lib/python2.2/doctest.py", line 798, in rundoc
    f2, t2 = self.run__test__(d, name)
<...>

It's definitely not a fault of getmro(). Besides, I've
tested and the crash occurs on Python 2.1, 2.2 and 2.3.

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

Comment By: Terry J. Reedy (tjreedy)
Date: 2003-12-29 00:05

Message:
Logged In: YES 
user_id=593130

Traceback says crash happens in inspect.getmro and not in 
doctest itself.  In 2.2.1, I get

>>> class C: pass
...
>>> C.c=C
>>> import inspect as i
>>> i.getmro(C)
(<class __main__.C at 0x00867510>,)

However, mro resolution was changed for 2.3.  See if above 
changes in 2.3.  Or if calling on class inside imported module 
makes a difference.


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

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