[ python-Bugs-891637 ] pydoc crashes on a class property

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Bugs item #891637, was opened at 2004-02-06 09:44
Message generated for change (Comment added) made by jlgijsbers
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=105470&aid=891637&group_id=5470

Category: Demos and Tools
Group: Python 2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Matthias Klose (doko)
Assigned to: Nobody/Anonymous (nobody)
Summary: pydoc crashes on a class property

Initial Comment:
[forwarded from http://bugs.debian.org/231202]

---
class foo(object): 
    __slots__ = ['_bar'] 
    bar = property(lambda (self): self._bar) 
    def __init__(self, bar): self._bar = bar 
 
f = foo(1) 
assert(f.bar == 1) 
---

removing the parenthesis around the lambda's parameter 
avoids the pydoc crash. Python itself doesn't seem to
care about the parenthesis.

$ python tmp.py  # no errors
$ pydoc tmp 
Traceback (most recent call last): 
  File "/usr/bin/pydoc", line 4, in ? 
    pydoc.cli() 
  File "/usr/lib/python2.3/pydoc.py", line 2123, in cli 
    help.help(arg) 
  File "/usr/lib/python2.3/pydoc.py", line 1582, in help 
    elif request: doc(request, 'Help on %s:') 
  File "/usr/lib/python2.3/pydoc.py", line 1375, in doc 
    pager(title % desc + '\n\n' + text.document(object,
name)) 
  File "/usr/lib/python2.3/pydoc.py", line 283, in
document 
    if inspect.ismodule(object): return
self.docmodule(*args) 
  File "/usr/lib/python2.3/pydoc.py", line 990, in
docmodule 
    contents.append(self.document(value, key, name)) 
  File "/usr/lib/python2.3/pydoc.py", line 284, in
document 
    if inspect.isclass(object): return
self.docclass(*args) 
  File "/usr/lib/python2.3/pydoc.py", line 1135, in
docclass 
    lambda t: t[1] == 'property') 
  File "/usr/lib/python2.3/pydoc.py", line 1087, in
spillproperties 
    base = self.document(func, tag, mod) 
  File "/usr/lib/python2.3/pydoc.py", line 285, in
document 
    if inspect.isroutine(object): return
self.docroutine(*args) 
  File "/usr/lib/python2.3/pydoc.py", line 1177, in
docroutine 
    args, varargs, varkw, defaults =
inspect.getargspec(object) 
  File "/usr/lib/python2.3/inspect.py", line 656, in
getargspec 
    args, varargs, varkw = getargs(func.func_code) 
  File "/usr/lib/python2.3/inspect.py", line 624, in
getargs 
    remain[-1] = remain[-1] - 1 
IndexError: list index out of range 


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Comment By: Johannes Gijsbers (jlgijsbers)
Date: 2004-08-08 12:23

Message:
Logged In: YES 
user_id=469548

First, note that the problem doesn't lie in properties. This
crashes as well:

foo = lambda  (bar): 1

second, Python does care about the parentheses. It just
doesn't matter when the lambda has only one argument. Using
parentheses creates a sublist instead of a parameter list,
as in the following example with normal functions:

def foo((bar, baz)): return bar
assert(foo((1, 2)) == 1)

pydoc (or rather, inspect) should still be fixed though.

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

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=105470&aid=891637&group_id=5470