This decrepancy between 2.x and 3.x is witnessed under Windows:

Python 2.7.1 (r271:86832, Nov 27 2010, 17:19:03) [MSC v.1500 64 bit (AMD64)] on
win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import socket
>>> sock = socket.create_connection(("www.python.org", 80))
>>> sock.close()
>>> sock.send(b"x")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "c:\python27\lib\socket.py", line 170, in _dummy
    raise error(EBADF, 'Bad file descriptor')
socket.error: [Errno 9] Bad file descriptor

Python 3.2.1 (default, Jul 10 2011, 20:02:51) [MSC v.1500 64 bit (AMD64)] on win
32
Type "help", "copyright", "credits" or "license" for more information.
>>> import socket
>>> sock = socket.socket(); sock.connect(("www.python.org", 80))
>>> sock.close()
>>> sock.send(b"x")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
socket.error: [Errno 10038] An operation was attempted on something that is not
a socket


I'm not sure this is worth fixing, though.

discrepancy, not decrepancy :S

(10038 is WSAENOTSOCK, by the way)

According to strace, Python 3 is calling send(-1, ...):

sendto(-1, "x", 1, 0, NULL, 0)          = -1 EBADF (Bad file descriptor)

A related discrepancy between Python 2 and 3 is how the socket.makefile() objects affect the original socket. In Python 2:

>>> f = sock.makefile("wb")
>>> sock.close()  # Should “close” Python’s sock object, but not f
>>> sock.send(b"x")
socket.error: [Errno 9] Bad file descriptor

In Python 3:
>>> sock.send(b"x")  # Actually sent to remote end!
1