incorrect DeprecationWarning?

[Alan G Isaac]

> 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?



On 9/4/2009 6:42 PM, Terry Reedy wrote:
> 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.



Exactly!

I think you are missing my point.
I understand it is just a DeprecationWarning.
But **why** should I receive a deprecation warning
when I am **not** using the deprecated practice?
Since I am **not** using the deprecated practice, the
warning is incorrect. (See the class definition above.)
And this incorrect warning affects a lot of people!

What anyone who is **not** using the deprecated practice
should expect in Python 2.6 is the Py3 behavior.  That is
not what we get: we get instead an incorrect deprecation
warning.

Alan Isaac