incorrect DeprecationWarning?

[Terry Reedy]

Alan G Isaac wrote:
> Python 2.6.2 (r262:71605, Apr 14 2009, 22:40:02) [MSC v.1500 32 bit 
> (Intel)] on win32
> Type "help", "copyright", "credits" or "license" for more information.
>>>> class MyError(Exception):
> ...     def __init__(self, message):
> ...         Exception.__init__(self)
> ...         self.message = message
> ...
>>>> e = MyError('msg')
> __main__:4: DeprecationWarning: BaseException.message has been 
> deprecated as of Python 2.6
> 
> 
> So?  Why would that mean I cannot add such an attribute
> to derived classes?

It does not mean that. Try printing e.message and you should see 'msg'.
I believe what it does mean is the the special meaning of 
exception.message (I have forgotten what it is) is gone in Python 3.

In Py3
class MyError(Exception):
      def __init__(self, message):
          Exception.__init__(self)
          self.message = message

e = MyError('msg')
print(e.message)

# 'msg'

No warning any more.

> Beyond odd.  A bug?

No. A warning about a 'future' change in behavior.

tjr