[ python-Bugs-1448639 ] asyncore dispatcher.__getattr__() masks self._map

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Bugs item #1448639, was opened at 2006-03-13 04:52
Message generated for change (Comment added) made by gbrandl
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Category: Python Library
Group: Python 2.4
>Status: Closed
>Resolution: Invalid
Priority: 5
Submitted By: Doug White (dwhite)
Assigned to: Nobody/Anonymous (nobody)
Summary: asyncore dispatcher.__getattr__() masks self._map

Initial Comment:
The abstraction of socket_map in the asyncore module 
in Python 2.4 forgets to allow accesses to the 
internal attribute self._map in __getattr__(). This 
causes any asyncore application to fail in 
create_socket(), which pretty much renders asyncore 
inoperative in Python 2.4.  
 
This problem was introduced in rev 34469 as a commit 
of Bug #758241. 
 
Example backtrace, generated from an application that 
uses Medusa servers that don't use the private map 
function: 
 
Traceback (most recent call last): 
  File "/usr/local/qos/qosserver/qos_server.py", line 
1576, in ? 
    m = monitor.monitor_server ('127.0.0.1', 
BasePort) 
  File "/usr/local/qos/qosserver/monitor.py", line 
161, in __init__ 
    self.create_socket (socket.AF_INET, 
socket.SOCK_STREAM) 
  File "/usr/local/lib/python2.4/asyncore.py", line 
261, in create_socket 
    self.add_channel() 
  File "/usr/local/lib/python2.4/asyncore.py", line 
244, in add_channel 
    map = self._map 
  File "/usr/local/lib/python2.4/asyncore.py", line 
366, in __getattr__ 
    return getattr(self.socket, attr) 
AttributeError: '_socketobject' object has no 
attribute '_map' 
 
__getattr__() should test if the attribute exists in 
its own object before passing it on to the underlying 
socket object. 

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>Comment By: Georg Brandl (gbrandl)
Date: 2006-03-17 11:51

Message:
Logged In: YES 
user_id=849994

It seems that zseil is right. Closing as Invalid.

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Comment By: Žiga Seilnacht (zseil)
Date: 2006-03-17 11:37

Message:
Logged In: YES 
user_id=1326842

This is a bug in your code, since you don't call the
base class's __init__() method, and as a consequence
the '_map' attribute really doesn't exist.

__getattr__() doesn't have to check for existance of
an attribute since it is called only when the normal
lookup mechanism fails. See the docs:
http://docs.python.org/ref/attribute-access.html



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