[Python-Dev] Inconsistency in 2.4.3 for repr() returning unicode (original) (raw)

M.-A. Lemburg mal at egenix.com
Mon Mar 27 12:14:50 CEST 2006

Hye-Shik Chang wrote:

We got an inconsistency for repr() returning unicode as reported in http://python.org/sf/1459029 :

class s1: def repr(self): return '\n' class s2: def repr(self): return u'\n' print repr(s1()), repr(s2()) Until 2.4.2: \n \n 2.4.3: \n \n \n looks bit weird but it's correct. As once discussed[1] in python-dev before, if repr returns unicode object, PyObjectRepr encodes it via unicode-escape codec. So, non-latin character also could be in repr neutrally.

I don't think that using unicode-escape is the right choice for converting a string returned by repr to a string - why would you want to escape a Unicode string that was specifically prepared to provide the representation of an object ?

But our unicode-escape had a bug since when it is introduced. The bug was that it doesn't escape backslashes. Therefore, backslashes wasn't escaped in repr while it sholud be escaped because we used the unicode-escape codec.

So, fixing the bug made a behavior inconsistency. How do we resolve the problem?

Change PyObject_Repr() to use the default encoding (again) which is also consistent with how PyObject_Str() works.

To make repr() conversion more robust, we could have PyObject_Repr() apply the conversion using the 'replace' error strategy - after all, repr() is usually only used for debugging, where it's more important that you do get an output rather than an exception.

Hye-Shik

[1] http://mail.python.org/pipermail/python-dev/2000-July/005353.html

-- Marc-Andre Lemburg eGenix.com

Professional Python Services directly from the Source (#1, Mar 27 2006)

Python/Zope Consulting and Support ... http://www.egenix.com/ mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/ mxODBC, mxDateTime, mxTextTools ... http://python.egenix.com/

::: Try mxODBC.Zope.DA for Windows,Linux,Solaris,FreeBSD for free ! ::::

More information about the Python-Dev mailing list