[Python-Dev] Issue 3745 backwards incompatibility (original) (raw)

Michael Foord fuzzyman at voidspace.org.uk
Tue Dec 15 12:29:56 CET 2009

On 15/12/2009 11:23, M.-A. Lemburg wrote:

Karen Tracey wrote:

In testing some existing code with the 2.7 alpha release, I've run into:

TypeError: Unicode-objects must be encoded before hashing when the existing code tries to pass unicode objects to hashlib.sha1 and hashlib.md5. This is, I believe, due to changes made for issue 3745: http://bugs.python.org/issue3745 The issue states the need to reject unencoded strings based on the fact that one backend implementation (openssl) refused to accept them while another (sha256) assumed a utf-8 encoding. The thing is, I cannot observe any such difference using Python 2.5 or 2.6. Instead of what is shown in the ticket (which was done on a Python 3, I believe) I see, when I adjust the demo test to use Python 2 syntax for "unencoded strings": I think this was a misunderstanding during the issue 3745 processing: the patch should not have been backported to trunk at all. For Python 3.x, the change was correct. For 2.x, a -3 warning would have been a better fit. Note that the non-OpenSSL SHA et al. modules have never defaulted to encoding to UTF-8 in Python 2.x. Python 2.x uses ASCII as default encoding. Only Python 3.x uses UTF-8 as default encoding.

Doesn't Python 3 use the platform encoding as the default (which happens to be UTF-8 on sensible systems but is something truly horrible like CP1250 on Windows)? (So assuming a default encoding of UTF-8 is still incorrect on Python 3 if we are being consistent with other IO behaviour.)

All the best,

Michael

I've added a note to the issue and reopened it.

-- http://www.ironpythoninaction.com/ http://www.voidspace.org.uk/blog

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