gistfile1.txt

def reposetup(ui, repo):
    class extrarepo(repo.__class__):
        def commit(self, self, text="", user=None, date=None, match=None, force=False,
                   editor=False, extra=None):
            extra = extra or {}
            # modify extra
            return super(extrarepo, self).commit(text=text, user=user, ...)
            
    repo.__class__ = extrarepo