bpo-34246: Use no mutable default args in smtplib (GH-8554)
Some methods of the SMTP class use mutable default arguments. Specially
`send_message` is affected as it mutates one of the args by appending items
to it, which has side effects on further calls.
(cherry picked from commit d5fbe9b1a3d65ceeb9159c5ba999ee966a945f76)
Co-authored-by: Pablo Aguiar <scorphus@gmail.com>
diff --git a/Lib/smtplib.py b/Lib/smtplib.py
index b679875..048c6bf 100755
--- a/Lib/smtplib.py
+++ b/Lib/smtplib.py
@@ -513,7 +513,7 @@
"""SMTP 'noop' command -- doesn't do anything :>"""
return self.docmd("noop")
- def mail(self, sender, options=[]):
+ def mail(self, sender, options=()):
"""SMTP 'mail' command -- begins mail xfer session.
This method may raise the following exceptions:
@@ -534,7 +534,7 @@
self.putcmd("mail", "FROM:%s%s" % (quoteaddr(sender), optionlist))
return self.getreply()
- def rcpt(self, recip, options=[]):
+ def rcpt(self, recip, options=()):
"""SMTP 'rcpt' command -- indicates 1 recipient for this mail."""
optionlist = ''
if options and self.does_esmtp:
@@ -785,8 +785,8 @@
raise SMTPResponseException(resp, reply)
return (resp, reply)
- def sendmail(self, from_addr, to_addrs, msg, mail_options=[],
- rcpt_options=[]):
+ def sendmail(self, from_addr, to_addrs, msg, mail_options=(),
+ rcpt_options=()):
"""This command performs an entire mail transaction.
The arguments are:
@@ -890,7 +890,7 @@
return senderrs
def send_message(self, msg, from_addr=None, to_addrs=None,
- mail_options=[], rcpt_options={}):
+ mail_options=(), rcpt_options=()):
"""Converts message to a bytestring and passes it to sendmail.
The arguments are as for sendmail, except that msg is an
@@ -958,7 +958,7 @@
if international:
g = email.generator.BytesGenerator(
bytesmsg, policy=msg.policy.clone(utf8=True))
- mail_options += ['SMTPUTF8', 'BODY=8BITMIME']
+ mail_options = (*mail_options, 'SMTPUTF8', 'BODY=8BITMIME')
else:
g = email.generator.BytesGenerator(bytesmsg)
g.flatten(msg_copy, linesep='\r\n')
diff --git a/Lib/test/test_smtplib.py b/Lib/test/test_smtplib.py
index 495764f..8a29e98 100644
--- a/Lib/test/test_smtplib.py
+++ b/Lib/test/test_smtplib.py
@@ -20,6 +20,7 @@
import unittest
from test import support, mock_socket
from test.support import HOST, HOSTv4, HOSTv6
+from unittest.mock import Mock
if sys.platform == 'darwin':
@@ -578,6 +579,33 @@
"localhost:bogus")
+class DefaultArgumentsTests(unittest.TestCase):
+
+ def setUp(self):
+ self.msg = EmailMessage()
+ self.msg['From'] = 'Páolo <főo@bar.com>'
+ self.smtp = smtplib.SMTP()
+ self.smtp.ehlo = Mock(return_value=(200, 'OK'))
+ self.smtp.has_extn, self.smtp.sendmail = Mock(), Mock()
+
+ def testSendMessage(self):
+ expected_mail_options = ('SMTPUTF8', 'BODY=8BITMIME')
+ self.smtp.send_message(self.msg)
+ self.smtp.send_message(self.msg)
+ self.assertEqual(self.smtp.sendmail.call_args_list[0][0][3],
+ expected_mail_options)
+ self.assertEqual(self.smtp.sendmail.call_args_list[1][0][3],
+ expected_mail_options)
+
+ def testSendMessageWithMailOptions(self):
+ mail_options = ['STARTTLS']
+ expected_mail_options = ('STARTTLS', 'SMTPUTF8', 'BODY=8BITMIME')
+ self.smtp.send_message(self.msg, None, None, mail_options)
+ self.assertEqual(mail_options, ['STARTTLS'])
+ self.assertEqual(self.smtp.sendmail.call_args_list[0][0][3],
+ expected_mail_options)
+
+
# test response of client to a non-successful HELO message
class BadHELOServerTests(unittest.TestCase):