id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
1664	Lazy evalutation doesn't work properly for returned Unicode objects	Noah Slater	hugo	"When you use ''utils.functional.lazy()'' to defer the return of a Unicode object Python's deep Unicode magic screws up data access.

Python uses a backdoor to check that a class is a Unicode object and will call special methods if this is so.

The following will work (the Unicode string is not encoded):

{{{
unicode_string = u""\xe9""
another_unicode_string = ""%s"" % unicode_string
}}}

This is because in this instance Python spots the Unicode object and calls the ''{{{__unicode__}}}'' method.

The following will not work (Python tries to encode the Unicode string to 'ASCII' or whatever the default is)

{{{

from django.utils.functional import lazy

def get_text(text)
    return text

lazy_get_text = lazy(get_text, Unicode)

lazy_unicode_string = lazy_get_text(u""\xe9"")

another_unicode_string = ""%s"" % lazy_unicode_string 
}}}

The reason this doesn't work is because the ACTUAL type of ''lazy_unicode_string'' is ''{{{__proxy__}}}'' or ''Promise''. Python sees this and calls the ''{{{__str__}}}'' method on the Unicode object which forces an attempt to encode to 'ASCII' or whatever the default is.

I can't see a solution to this - but I thought I would raise a ticket just so you guys were aware. I have seen that the issue of full internal Unicode usage is being discussed and this is quiet relevant I should imagine.

This issue is covered in [http://www.python.org/dev/peps/pep-0349/ PEP 349]. It's worth noting that [http://sourceforge.net/tracker/index.php?func=detail&aid=1266570&group_id=5470&atid=305470 a patch DOES exist] for Python which would remove these problems - though I do not know when, or in fact it, it will be rolled into Python proper.
"	defect	closed	Internationalization		normal	wontfix		nslater@…	Unreviewed	0	0	0	0	0	0