smtpd.SMTPChannel contains a bug such that when connected to an 
SMTPServer (or any subclass thereof), issuing a MAIL command with no 
argument closes the socket and gives this error on the server:

(<type 'exceptions.TypeError'>:'NoneType' object is unsubscriptable ... 
smtpd.py|__getaddr|212])

The desired result is of course is to respond with a 501 Syntax error. 
The problem arises because the arg parameter passed to each smtp_* 
command handler function is None when there is no argument. arg is 
passed on to __getaddr which attempts a slice on the None object.

A check for None in __getaddr that returns will allow the existing code 
to issue the appropriate 501 Syntax error.

Very simple patch that adds a ternary operator to skip the call to 
__getaddr if there is no arg.

Thanks!

Committed revision 58594.

Is there time to backport this to 2.5.2?

It would be great to get this into 2.5.2.

Thanks for the patch.

Committed revision 58599. (2.5)

I'm really sorry I didn't notice this earlier, but RCPT has the same bug! 
This patch applies the same fix to that function as well.

Committed revision 58618.

There better not be any others. :-)

Neal, can you add this to 2.5.2 and then close?

Committed revision 58625. (2.5)