[Python-Dev] PEP 409 and the stdlib

[Eric V. Smith]

On May 20, 2013, at 11:46 AM, Antoine Pitrou <solipsis at pitrou.net> wrote:

> On Mon, 20 May 2013 07:12:07 -0700
> Ethan Furman <ethan at stoneleaf.us> wrote:
>> 
>> As a case in point, base64.py is currently getting a bug fix, and also contains this code:
>> 
>> def b32decode(s, casefold=False, map01=None):
>>     .
>>     .
>>     .
>>     for i in range(0, len(s), 8):
>>         quanta = s[i: i + 8]
>>         acc = 0
>>         try:
>>             for c in quanta:
>>                 acc = (acc << 5) + b32rev[c]
>>         except KeyError:
>>             raise binascii.Error('Non-base32 digit found')
>>     .
>>     .
>>     .
>>         else:
>>             raise binascii.Error('Incorrect padding')
>> 
>> Does the KeyError qualify as irrelevant noise?
> 
> I think it is a legitimate case where to silence the original
> exception. However, the binascii.Error would be more informative if it
> said *which* non-base32 digit was encountered.
> 

And, if possible, the location (index) in the string. 

Eric.