Don't include the domain name in exception message text before its syntax is validated

The domain name might have unsafe characters. In any case, the user probably knows what they entered and doesn't need it repeated back to them.

Author: JoshData

email_validator/syntax.py

@@ -128,7 +128,7 @@ def validate_email_domain_part(domain, test_environment=False, globally_delivera
     try:
         domain = idna.uts46_remap(domain, std3_rules=False, transitional=False)
     except idna.IDNAError as e:
-        raise EmailSyntaxError("The domain name %s contains invalid characters (%s)." % (domain, str(e)))
+        raise EmailSyntaxError("The part after the @-sign contains invalid characters ({}).".format(str(e)))
 
     # Now we can perform basic checks on the use of periods (since equivalent
     # symbols have been mapped to periods). These checks are needed because the
@@ -166,7 +166,7 @@ def validate_email_domain_part(domain, test_environment=False, globally_delivera
                 # one the user supplied. Also I'm not sure if the length check applies
                 # to the internationalized form, the IDNA ASCII form, or even both!
                 raise EmailSyntaxError("The email address is too long after the @-sign.")
-            raise EmailSyntaxError("The domain name %s contains invalid characters (%s)." % (domain, str(e)))
+            raise EmailSyntaxError("The part after the @-sign contains invalid characters (%s)." % str(e))
 
         # Check the syntax of the string returned by idna.encode.
         # It should never fail.
@@ -186,7 +186,7 @@ def validate_email_domain_part(domain, test_environment=False, globally_delivera
     for label in ascii_domain.split("."):
         if len(label) > DNS_LABEL_LENGTH_LIMIT:
             reason = get_length_reason(label, limit=DNS_LABEL_LENGTH_LIMIT)
-            raise EmailSyntaxError("The part of the email address \"{}\" is too long {}.".format(label, reason))
+            raise EmailSyntaxError("On either side of the @-sign, periods cannot be separated by so many characters {}.".format(reason))
 
     if globally_deliverable:
         # All publicly deliverable addresses have domain named with at least
@@ -223,7 +223,7 @@ def validate_email_domain_part(domain, test_environment=False, globally_delivera
     try:
         domain_i18n = idna.decode(ascii_domain.encode('ascii'))
     except idna.IDNAError as e:
-        raise EmailSyntaxError("The domain name %s is not valid IDNA (%s)." % (ascii_domain, str(e)))
+        raise EmailSyntaxError("The part after the @-sign is not valid IDNA ({}).".format(str(e)))
 
     # Return the IDNA ASCII-encoded form of the domain, which is how it
     # would be transmitted on the wire (except when used with SMTPUTF8

tests/test_main.py

@@ -218,22 +218,22 @@ def test_email_valid(email_input, output):
         ('my@..twodots.com', 'An email address cannot have a period immediately after the @-sign.'),
         ('my@twodots..com', 'An email address cannot have two periods in a row.'),
         ('my@baddash.-.com',
-         'The domain name baddash.-.com contains invalid characters (Label must not start or end with a hyphen).'),
+         'The part after the @-sign contains invalid characters (Label must not start or end with a hyphen).'),
         ('my@baddash.-a.com',
-         'The domain name baddash.-a.com contains invalid characters (Label must not start or end with a hyphen).'),
+         'The part after the @-sign contains invalid characters (Label must not start or end with a hyphen).'),
         ('my@baddash.b-.com',
-         'The domain name baddash.b-.com contains invalid characters (Label must not start or end with a hyphen).'),
+         'The part after the @-sign contains invalid characters (Label must not start or end with a hyphen).'),
         ('my@example.com\n',
-         'The domain name example.com\n contains invalid characters (Codepoint U+000A at position 4 of '
+         'The part after the @-sign contains invalid characters (Codepoint U+000A at position 4 of '
          '\'com\\n\' not allowed).'),
         ('my@example\n.com',
-         'The domain name example\n.com contains invalid characters (Codepoint U+000A at position 8 of '
+         'The part after the @-sign contains invalid characters (Codepoint U+000A at position 8 of '
          '\'example\\n\' not allowed).'),
         ('.leadingdot@domain.com', 'The email address contains invalid characters before the @-sign: FULL STOP.'),
         ('..twodots@domain.com', 'The email address contains invalid characters before the @-sign: FULL STOP.'),
         ('twodots..here@domain.com', 'The email address contains invalid characters before the @-sign: FULL STOP.'),
         ('me@⒈wouldbeinvalid.com',
-         "The domain name ⒈wouldbeinvalid.com contains invalid characters (Codepoint U+2488 not allowed "
+         "The part after the @-sign contains invalid characters (Codepoint U+2488 not allowed "
          "at position 1 in '⒈wouldbeinvalid.com')."),
         ('@example.com', 'There must be something before the @-sign.'),
         ('\nmy@example.com', 'The email address contains invalid characters before the @-sign: \'\\n\'.'),