don't rely on hasattr in utils.dir2

Some remote object libraries (e.g. Pyro) will lie to hasattr, not raising AttributeError until the attr is actually requested.
This prevents these AttributeErrors from crashing IPython.

closes gh-543

Signed-off-by: MinRK <[e-mail]>

IPython/utils/dir2.py

@@ -1,82 +1,94 b''
 # encoding: utf-8
 """A fancy version of Python's builtin :func:`dir` function.
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2009  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Code
 #-----------------------------------------------------------------------------
 
 def get_class_members(cls):
     ret = dir(cls)
     if hasattr(cls,'__bases__'):
-        for base in cls.__bases__:
-            ret.extend(get_class_members(base))
+        try:
+            bases = cls.__bases__
+        except AttributeError:
+            # `obj` lied to hasattr (e.g. Pyro), ignore
+            pass
+        else:
+            for base in bases:
+                ret.extend(get_class_members(base))
     return ret
 
 
 def dir2(obj):
     """dir2(obj) -> list of strings
 
     Extended version of the Python builtin dir(), which does a few extra
     checks, and supports common objects with unusual internals that confuse
     dir(), such as Traits and PyCrust.
 
     This version is guaranteed to return only a list of true strings, whereas
     dir() returns anything that objects inject into themselves, even if they
     are later not really valid for attribute access (many extension libraries
     have such bugs).
     """
 
     # Start building the attribute list via dir(), and then complete it
     # with a few extra special-purpose calls.
     words = dir(obj)
 
     if hasattr(obj,'__class__'):
         words.append('__class__')
         words.extend(get_class_members(obj.__class__))
     #if '__base__' in words: 1/0
 
     # Some libraries (such as traits) may introduce duplicates, we want to
     # track and clean this up if it happens
     may_have_dupes = False
 
     # this is the 'dir' function for objects with Enthought's traits
     if hasattr(obj, 'trait_names'):
         try:
             words.extend(obj.trait_names())
             may_have_dupes = True
         except TypeError:
             # This will happen if `obj` is a class and not an instance.
             pass
+        except AttributeError:
+            # `obj` lied to hasatter (e.g. Pyro), ignore
+            pass
 
     # Support for PyCrust-style _getAttributeNames magic method.
     if hasattr(obj, '_getAttributeNames'):
         try:
             words.extend(obj._getAttributeNames())
             may_have_dupes = True
         except TypeError:
             # `obj` is a class and not an instance.  Ignore
             # this error.
             pass
+        except AttributeError:
+            # `obj` lied to hasatter (e.g. Pyro), ignore
+            pass
 
     if may_have_dupes:
         # eliminate possible duplicates, as some traits may also
         # appear as normal attributes in the dir() call.
         words = list(set(words))
         words.sort()
 
     # filter out non-string attributes which may be stuffed by dir() calls
     # and poor coding in third-party modules
     return [w for w in words if isinstance(w, basestring)]