Message11637

Incidental to working on #2632, I noticed that mixed comparisons of unicode and str do not produce the same results in Jython as in CPython.

CPython:

>>> u = u"caf\xe9"
>>> u == u.encode('latin-1')
__main__:1: UnicodeWarning: Unicode equal comparison failed to convert both arguments to Unicode - interpreting them as being unequal
False

Jython:

>>> u = u"caf\xe9"
>>> u == u.encode('latin-1')
True

CPython converts the str (or whatever is opposite on the operator) into a unicode, if it can, using the default encoding. Jython just compares the internal Java string without reference to the default encoding. The default is ASCII normally, but may be changed with sys.setdefaultencoding('utf-8'), which is likely to happen exactly when this kind of encoding is significant to use.

We should check all the binary operation of PyUnicode for this problem.