Email validator: don't allow whitespace in the address

See sections 3.4.1 and 3.2.4 of RFC 2822.

From my reading, you can *technically* include whitespace if it's quoted, but
for our purposes it's almost certainly going to be a mistake we want to notify
the user about.

r2/r2/lib/validator/validator.py

@@ -2050,6 +2050,11 @@ class ValidEmail(Validator):
     """Validates a single email. Returns the email on success."""
 
     def run(self, email):
+        # Strip out leading/trailing whitespace, since the inclusion of that is
+        # a common and easily-fixable user error.
+        if email is not None:
+            email = email.strip()
+
         if not email:
             self.set_error(errors.NO_EMAIL)
         elif not ValidEmails.email_re.match(email):
@@ -2065,7 +2070,7 @@ class ValidEmails(Validator):
     success"""
 
     separator = re.compile(r'[^\s,;]+')
-    email_re  = re.compile(r'.+@.+\..+')
+    email_re  = re.compile(r'[^\s]+@[^\s]+\.[^\s]+')
 
     def __init__(self, param, num = 20, **kw):
         self.num = num

r2/r2/tests/unit/lib/validator/test_validator.py

@@ -61,6 +61,17 @@ class TestValidEmail(unittest.TestCase):
 
     def test_blank_email(self):
         self._test_failure('', errors.NO_EMAIL)
+        self.setUp()
+        self._test_failure(' ', errors.NO_EMAIL)
+
+    def test_no_whitespace(self):
+        self._test_failure('test @example.com')
+        self.setUp()
+        self._test_failure('test@ example.com')
+        self.setUp()
+        self._test_failure('test@example. com')
+        self.setUp()
+        self._test_failure("test@\texample.com")
 
     def test_no_hostname(self):
         self._test_failure('example')