Email validator does not allow double hyphen

[dAnjou]

lorem@i--ipsum.com is a valid email address but the current email validator doesn't validate it.

Here's an email validator that I wrote with code that I stole from Django which works:

class Email(object):
    """
    Email validator shamelessly stolen from Django
    """
    USER_REGEX = (
        r"(^[-!#$%&'*+/=?^_`{}|~0-9A-Z]+(\.[-!#$%&'*+/=?^_`{}|~0-9A-Z]+)*\Z"  # dot-atom
        r'|^"([\001-\010\013\014\016-\037!#-\[\]-\177]|\\[\001-\011\013\014\016-\177])*"\Z)'  # quoted-string
    )
    # max length for domain name labels is 63 characters per RFC 1034
    DOMAIN_REGEX = r'((?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+)(?:[A-Z0-9-]{2,63}(?<!-))\Z'

    def __init__(self, msg=None):
        if msg is None:
            msg = "Invalid email address"
        self.msg = msg
        self.user_regex = re.compile(self.USER_REGEX, re.IGNORECASE)
        self.domain_regex = re.compile(self.DOMAIN_REGEX, re.IGNORECASE)

    def __call__(self, node, value):
        if not value or '@' not in value:
            raise Invalid(node, self.msg)

        user_part, domain_part = value.rsplit('@', 1)

        if not self.user_regex.match(user_part):
            raise Invalid(node, self.msg)

        if not self.domain_regex.match(domain_part):
            # Try for possible IDN domain-part
            try:
                domain_part = domain_part.encode('idna').decode('ascii')
                if self.domain_regex.match(domain_part):
                    return
            except UnicodeError:
                pass
            raise Invalid(node, self.msg)

[robertknight]

In fixing this for our project I opted to use an email regex taken from Chrome based on the HTML specs, on the basis that pattern is widely used and is pretty simple.

Would this be accepted upstream?

[digitalresistor]

I'd be willing to accept that regex. Since that is what the browser is using for validation.