Add minimal savepoint support, so we do not fail if any code tries to…

… create a savepoint.

Fixes issue #35.

CHANGES.rst

@@ -5,6 +5,9 @@
 5.2 (unreleased)
 ================
 
+- Add minimal savepoint support, so we do not fail if any code tries to create a savepoint.
+  (`#35 <https://github.com/zopefoundation/zope.sendmail/issues/35>`_).
+
 - Fix TypeError: 'error' object is not subscriptable during error handling on
   Windows (`#33 <https://github.com/zopefoundation/zope.sendmail/pull/33>`_).
 

src/zope/sendmail/delivery.py

@@ -25,7 +25,8 @@
 from time import strftime
 from socket import gethostname
 
-from transaction.interfaces import IDataManager
+from transaction.interfaces import ISavepointDataManager
+from transaction.interfaces import IDataManagerSavepoint
 import transaction
 
 from zope.interface import implementer
@@ -41,7 +42,14 @@
 log = logging.getLogger("MailDataManager")
 
 
-@implementer(IDataManager)
+@implementer(IDataManagerSavepoint)
+class _NoOpSavepoint(object):
+
+    def rollback(self):
+        return
+
+
+@implementer(ISavepointDataManager)
 class MailDataManager(object):
 
     def __init__(self, callable, args=(), vote=None, onAbort=None):
@@ -62,6 +70,12 @@ def abort(self, txn):
     def sortKey(self):
         return str(id(self))
 
+    def savepoint(self):
+        # We do not need savepoint/rollback, but some code (like CMFEditions)
+        # uses savepoints, and breaks when one datamanager does not have this.
+        # So provide a dummy implementation.
+        return _NoOpSavepoint()
+
     # No subtransaction support.
     def abort_sub(self, txn):
         "This object does not do anything with subtransactions"

src/zope/sendmail/tests/test_delivery.py

@@ -256,6 +256,35 @@ def send(self):
         self.assertEqual(1, len(w))
         self.assertIn("does not provide a vote method", str(w[0]))
 
+    def testSavepoint(self):
+        mailer = MailerStub()
+        delivery = DirectMailDelivery(mailer)
+        fromaddr = 'Jim <jim@example.com'
+        toaddrs = ('Guido <guido@example.com>',
+                   'Steve <steve@examplecom>')
+        opt_headers = (b'From: Jim <jim@example.org>\n'
+                       b'To: some-zope-coders:;\n'
+                       b'Date: Mon, 19 May 2003 10:17:36 -0400\n'
+                       b'Message-Id: <20030519.1234@example.org>\n')
+        message = (b'Subject: example\n'
+                   b'\n'
+                   b'This is just an example\n')
+
+        message_bytes = message
+        opt_headers_bytes = opt_headers
+
+        msgid = delivery.send(fromaddr, toaddrs, opt_headers + message)
+        self.assertEqual(msgid, '20030519.1234@example.org')
+        self.assertEqual(mailer.sent_messages, [])
+        savepoint = transaction.savepoint()
+        self.assertEqual(mailer.sent_messages, [])
+        savepoint.rollback()
+        self.assertEqual(mailer.sent_messages, [])
+        transaction.commit()
+        self.assertEqual(mailer.sent_messages,
+                         [(fromaddr, toaddrs,
+                           opt_headers_bytes + message_bytes)])
+
 
 class MaildirWriterStub(object):