MySQL backend fixes for Python 3. With Python 2, text sent to and from MySQL is treated as bytes in Python. The database may be recorded by MySQL as having some other encoding (latin1 being the default in some MySQL versions - Roundup does not set an encoding explicitly, unlike in back_postgresql), but as long as MySQL's notion of the connection encoding agrees with its notion of the database encoding, no conversions actually take place and the bytes are stored and returned as-is. With Python 3, text sent to and from MySQL is treated as Python Unicode strings. When the database and connection encoding is latin1, that means the bytes stored in the database under Python 2 are interpreted as latin1 and converted from that to Unicode, producing incorrect results for any non-ASCII characters; furthermore, if trying to store new non-ASCII data in the database under Python 3, any non-latin1 characters produce errors. This patch arranges for both the connection and database character sets to be UTF-8 when using Python 3, and documents a need to export and import the database when moving from Python 2 to Python 3 with this backend.

class MockNull:
    def __init__(self, **kwargs):
        for key, value in kwargs.items():
            self.__dict__[key] = value

    def __call__(self, *args, **kwargs): return MockNull()
    def __getattr__(self, name):
        # This allows assignments which assume all intermediate steps are Null
        # objects if they don't exist yet.
        #
        # For example (with just 'client' defined):
        #
        # client.db.config.TRACKER_WEB = 'BASE/'
        self.__dict__[name] = MockNull()
        return getattr(self, name)

    def __getitem__(self, key): return self
    def __bool__(self): return False
    # Python 2 compatibility:
    __nonzero__ = __bool__
    def __contains__(self, key): return False
    def __eq__(self, rhs): return False
    def __ne__(self, rhs): return False
    def __str__(self): return ''
    def __repr__(self): return '<MockNull 0x%x>'%id(self)
    def gettext(self, str): return str
    _ = gettext