From 9b9c8c4a81ab67d1bc392b6fd9cc17e0b844f7ff Mon Sep 17 00:00:00 2001
From: Jon Dufresne <jon.dufresne@gmail.com>
Date: Fri, 21 Oct 2016 05:59:07 -0700
Subject: [PATCH] Fixed #27368 -- Modifed BaseEmailBackend.__enter__() to close
 the connection if an exception occurs.

Fixes unclosed socket ResourceWarning in mail test.

Thanks Claude Paroz for the review.
---
 django/core/mail/backends/base.py |  6 +++++-
 tests/mail/tests.py               | 27 +++++++++++----------------
 2 files changed, 16 insertions(+), 17 deletions(-)

diff --git a/django/core/mail/backends/base.py b/django/core/mail/backends/base.py
index 484d2a8b57..4914f479b9 100644
--- a/django/core/mail/backends/base.py
+++ b/django/core/mail/backends/base.py
@@ -40,7 +40,11 @@ class BaseEmailBackend(object):
         pass
 
     def __enter__(self):
-        self.open()
+        try:
+            self.open()
+        except Exception:
+            self.close()
+            raise
         return self
 
     def __exit__(self, exc_type, exc_value, traceback):
diff --git a/tests/mail/tests.py b/tests/mail/tests.py
index 662cd7c6d6..e053a65d6a 100644
--- a/tests/mail/tests.py
+++ b/tests/mail/tests.py
@@ -1289,11 +1289,9 @@ class SMTPBackendTests(BaseEmailBackendTests, SMTPBackendTestsBase):
         """
         backend = smtp.EmailBackend(
             username='not empty username', password='not empty password')
-        try:
-            with self.assertRaisesMessage(SMTPException, 'SMTP AUTH extension not supported by server.'):
-                backend.open()
-        finally:
-            backend.close()
+        with self.assertRaisesMessage(SMTPException, 'SMTP AUTH extension not supported by server.'):
+            with backend:
+                pass
 
     def test_server_open(self):
         """
@@ -1315,7 +1313,8 @@ class SMTPBackendTests(BaseEmailBackendTests, SMTPBackendTestsBase):
 
         backend = CustomEmailBackend(username='username', password='password')
         with self.assertRaises(SMTPAuthenticationError):
-            backend.open()
+            with backend:
+                pass
 
     @override_settings(EMAIL_USE_TLS=True)
     def test_email_tls_use_settings(self):
@@ -1377,21 +1376,17 @@ class SMTPBackendTests(BaseEmailBackendTests, SMTPBackendTestsBase):
     def test_email_tls_attempts_starttls(self):
         backend = smtp.EmailBackend()
         self.assertTrue(backend.use_tls)
-        try:
-            with self.assertRaisesMessage(SMTPException, 'STARTTLS extension not supported by server.'):
-                backend.open()
-        finally:
-            backend.close()
+        with self.assertRaisesMessage(SMTPException, 'STARTTLS extension not supported by server.'):
+            with backend:
+                pass
 
     @override_settings(EMAIL_USE_SSL=True)
     def test_email_ssl_attempts_ssl_connection(self):
         backend = smtp.EmailBackend()
         self.assertTrue(backend.use_ssl)
-        try:
-            with self.assertRaises(SSLError):
-                backend.open()
-        finally:
-            backend.close()
+        with self.assertRaises(SSLError):
+            with backend:
+                pass
 
     def test_connection_timeout_default(self):
         """Test that the connection's timeout value is None by default."""