Can you talk specifics about what does not work? Because if there is an actual unicode problem in click i want to fix it.

Would have to go over the rest of code, but the code in ClickException is broken:

    class ClickException(Exception):
        """An exception that Click can handle and show to the user."""

        #: The exit code for this exception
        exit_code = 1

        def __init__(self, message):
            ctor_msg = message
            if PY2:
                if ctor_msg is not None:
                    ctor_msg = ctor_msg.encode('utf-8')
            Exception.__init__(self, ctor_msg)
            self.message = message

        def format_message(self):
            return self.message

        def __unicode__(self):
            return self.message

        def __str__(self):
            return self.message.encode('utf-8')

        def show(self, file=None):
            if file is None:
                file = get_text_stderr()
            echo('Error: %s' % self.format_message(), file=file)

This code is arguably wrong. I think I understand what you were trying to do, but I'm not certain. There is a possibility to use it correctly in python 2 though, but many people might be not aware of it.

In python 3 you pass the message as is (it might cause another issue, but about that later).

In python 2 you immediately encode the passed variable using utf-8. This means that you're expecting argument to be of unicode type, but at the same time you're discouraging users to use unicode_literals, and in most situations users will pass a regular string.

In python 3 __str__ is trying to convert text to bytes, while the message would already be text. This most of the times will look correct, but it might spew garbage when there are non ascii characters.

Here's corrected code (did not test it though):

    if PY2:
      unicode = str

    class ClickException(Exception):
        """An exception that Click can handle and show to the user."""

        #: The exit code for this exception
        exit_code = 1

        def __init__(self, message):
            if PY2 and isinstance(self, unicode):
                message = message.encode()
            Exception.__init__(self, message)
            self.message = message

        def format_message(self):
            return self.message

        def __unicode__(self):
            return str(self).decode()

        def __str__(self):
            return str(self.message)

        def show(self, file=None):
            if file is None:
                file = get_text_stderr()
            echo('Error: %s' % self.format_message(), file=file)

There are few other things that gives headaches (not necessarily python 2 only).

In python 3 for example click refuses to run if LANG and LC_CTYPE are not defined. Why doesn't it simply do what all other applications are doing and simply fall back to latin-1 (ISO-8859-1) instead of printing the error.

Also, another issue (and my above code is also is affected by this). Click is checking for environmental variables before continuing, yet encode and decode have hardcoded utf-8. It probably should use whatever locale.getdefaultlocale() returns.