Unicode strings as arguments to exceptions

[Steven D'Aprano]

On Thu, 16 Jan 2014 13:34:08 +0100, Ernest Adrogué wrote:

> Hi,
> 
> There seems to be some inconsistency in the way exceptions handle
> Unicode strings.

Yes. I believe the problem lies in the __str__ method. For example, 
KeyError manages to handle Unicode, although in an ugly way:

py> str(KeyError(u'ä'))
"u'\\xe4'"

Hence:

py> raise KeyError(u'ä')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
KeyError: u'\xe4'


While ValueError assumes ASCII and fails:

py> str(ValueError(u'ä'))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
UnicodeEncodeError: 'ascii' codec can't encode character u'\xe4' in 
position 0: ordinal not in range(128)

When displaying the traceback, the error is suppressed, hence:

py> raise ValueError(u'ä')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError


I believe this might be accepted as a bug report on ValueError.


-- 
Steven