[Python-Dev] Re: test_string, test_unicode fail

[Guido van Rossum]

> Guido van Rossum wrote:
> > 
> > Today, test_string and test_unicode have started to fail.  I'm
> > suspicious that this is the result of changes Marc-Andre checked in to
> > make unicode() behave more like str().
> > 
> > A little investigation (not that the string test suite makes this easy
> > :-( ) shows that line 133 of string_tests.py checks to make sure that
> > 
> >     '.'.join('a', u'b', 3)
> > 
> > raise an exception.  But it now silently casts the 3 to u'3', so the
> > result is u'a.b.3'.
> 
> Oops. I forgot to run test_string.py -- I did run test_unicode.py
> and it passes; could be that I need to update the output of that
> test.

I don't know how to tell whether test_unicode.py passes or not from
looking at the output (which is inscrutable to me).  All I know is
that regrtest says it fails.

> > Is this really an good idea?  Was it an intended side effect?
> 
> The intention is to make str() and unicode() behave in the same
> way. It is not a side-effect. unicode() now behaves in the same
> way as str() always did.

Not true.  "".join(["a", 3]) raises a TypeError, and this is how it
should be.  So I expect that u"".join(["a", 3]) also raises TypeError,
not return u"a3" as it does now.

I urge you to reconsider how this change is implemented.  The implied
unicode() call for list items in the join() method is probably just
scratching the surface -- there are likely other places where now
suddenly everything is auto-converted to a unicode string.

--Guido van Rossum (home page: http://www.python.org/~guido/)