20 files changed, 105 insertions, 97 deletions
diff --git a/src/mailman/chains/base.py b/src/mailman/chains/base.py
index a2266cf38..54bddfe0b 100644
--- a/src/mailman/chains/base.py
+++ b/src/mailman/chains/base.py
@@ -114,8 +114,7 @@ class Chain:
         """Return an iterator over the links."""
         # We do it this way in order to preserve a separation of interfaces,
         # and allows .get_links() to be overridden.
-        for link in self._links:
-            yield link
+        yield from self._links
 
 
 
diff --git a/src/mailman/chains/tests/test_base.py b/src/mailman/chains/tests/test_base.py
index 7216a6178..dc50252c3 100644
--- a/src/mailman/chains/tests/test_base.py
+++ b/src/mailman/chains/tests/test_base.py
@@ -19,15 +19,22 @@
 
 __all__ = [
     'TestMiscellaneous',
+    'TestTerminalChainBase',
     ]
 
 
 import unittest
 
 from mailman.chains.accept import AcceptChain
-from mailman.chains.base import Chain, Link
+from mailman.chains.base import Chain, Link, TerminalChainBase
 from mailman.interfaces.chain import LinkAction
 from mailman.rules.any import Any
+from mailman.testing.layers import ConfigLayer
+
+
+class SimpleChain(TerminalChainBase):
+    def _process(self, mlist, msg, msgdata):
+        pass
 
 
 
@@ -75,3 +82,12 @@ class TestMiscellaneous(unittest.TestCase):
         chain.flush()
         count = sum(1 for link in chain.get_iterator())
         self.assertEqual(count, 0)
+
+
+class TestTerminalChainBase(unittest.TestCase):
+    layer = ConfigLayer
+
+    def test_terminal_chain_iterator(self):
+        chain = SimpleChain()
+        self.assertEqual([link.action for link in chain],
+                         [LinkAction.run, LinkAction.stop])
diff --git a/src/mailman/config/config.py b/src/mailman/config/config.py
index 69ddfb04f..424ad03c0 100644
--- a/src/mailman/config/config.py
+++ b/src/mailman/config/config.py
@@ -245,8 +245,7 @@ class Configuration:
     @property
     def runner_configs(self):
         """Iterate over all the runner configuration sections."""
-        for section in self._config.getByCategory('runner', []):
-            yield section
+        yield from self._config.getByCategory('runner', [])
 
     @property
     def archivers(self):
@@ -262,8 +261,7 @@ class Configuration:
     @property
     def language_configs(self):
         """Iterate over all the language configuration sections."""
-        for section in self._config.getByCategory('language', []):
-            yield section
+        yield from self._config.getByCategory('language', [])
 
 
 
diff --git a/src/mailman/config/tests/test_configuration.py b/src/mailman/config/tests/test_configuration.py
index 48cf21983..abbfce2c2 100644
--- a/src/mailman/config/tests/test_configuration.py
+++ b/src/mailman/config/tests/test_configuration.py
@@ -58,6 +58,21 @@ class TestConfiguration(unittest.TestCase):
                     pass
                 self.assertEqual(events, ['first', 'second', 'first'])
 
+    def test_config_template_dir_is_source(self):
+        fd, filename = tempfile.mkstemp()
+        self.addCleanup(os.remove, filename)
+        os.close(fd)
+        with open(filename, 'w') as fp:
+            print("""\
+[paths.here]
+template_dir: :source:
+""", file=fp)
+        config = Configuration()
+        config.load(filename)
+        import mailman.templates
+        self.assertEqual(config.TEMPLATE_DIR,
+                         os.path.dirname(mailman.templates.__file__))
+
 
 
 class TestExternal(unittest.TestCase):
diff --git a/src/mailman/core/pipelines.py b/src/mailman/core/pipelines.py
index a3c1bd58e..a353e3ad8 100644
--- a/src/mailman/core/pipelines.py
+++ b/src/mailman/core/pipelines.py
@@ -85,8 +85,7 @@ class BasePipeline:
 
     def __iter__(self):
         """See `IPipeline`."""
-        for handler in self._handlers:
-            yield handler
+        yield from self._handlers
 
 
 
diff --git a/src/mailman/model/bounce.py b/src/mailman/model/bounce.py
index e05bda516..3ccf58091 100644
--- a/src/mailman/model/bounce.py
+++ b/src/mailman/model/bounce.py
@@ -54,8 +54,6 @@ class BounceEvent(Model):
         self.email = email
         self.timestamp = now()
         msgid = msg['message-id']
-        if isinstance(msgid, bytes):
-            msgid = msgid.decode('ascii')
         self.message_id = msgid
         self.context = (BounceContext.normal if context is None else context)
         self.processed = False
@@ -77,12 +75,10 @@ class BounceProcessor:
     @dbconnection
     def events(self, store):
         """See `IBounceProcessor`."""
-        for event in store.query(BounceEvent).all():
-            yield event
+        yield from store.query(BounceEvent).all()
 
     @property
     @dbconnection
     def unprocessed(self, store):
         """See `IBounceProcessor`."""
-        for event in store.query(BounceEvent).filter_by(processed=False):
-            yield event
+        yield from store.query(BounceEvent).filter_by(processed=False)
diff --git a/src/mailman/model/domain.py b/src/mailman/model/domain.py
index 1218a3481..7fb6d6821 100644
--- a/src/mailman/model/domain.py
+++ b/src/mailman/model/domain.py
@@ -94,11 +94,9 @@ class Domain(Model):
     @dbconnection
     def mailing_lists(self, store):
         """See `IDomain`."""
-        mailing_lists = store.query(MailingList).filter(
+        yield from store.query(MailingList).filter(
             MailingList.mail_host == self.mail_host
             ).order_by(MailingList._list_id)
-        for mlist in mailing_lists:
-            yield mlist
 
     def confirm_url(self, token=''):
         """See `IDomain`."""
@@ -194,8 +192,7 @@ class DomainManager:
     @dbconnection
     def __iter__(self, store):
         """See `IDomainManager`."""
-        for domain in store.query(Domain).order_by(Domain.mail_host).all():
-            yield domain
+        yield from store.query(Domain).order_by(Domain.mail_host).all()
 
     @dbconnection
     def __contains__(self, store, mail_host):
diff --git a/src/mailman/model/listmanager.py b/src/mailman/model/listmanager.py
index fcf7a61e0..c4135a8c7 100644
--- a/src/mailman/model/listmanager.py
+++ b/src/mailman/model/listmanager.py
@@ -88,15 +88,13 @@ class ListManager:
     @dbconnection
     def mailing_lists(self, store):
         """See `IListManager`."""
-        for mlist in store.query(MailingList).order_by(
-                MailingList._list_id).all():
-            yield mlist
+        yield from store.query(MailingList).order_by(
+            MailingList._list_id).all()
 
     @dbconnection
     def __iter__(self, store):
         """See `IListManager`."""
-        for mlist in store.query(MailingList).all():
-            yield mlist
+        yield from store.query(MailingList).all()
 
     @property
     @dbconnection
@@ -105,7 +103,7 @@ class ListManager:
         result_set = store.query(MailingList)
         for mail_host, list_name in result_set.values(MailingList.mail_host,
                                                       MailingList.list_name):
-            yield '{0}@{1}'.format(list_name, mail_host)
+            yield '{}@{}'.format(list_name, mail_host)
 
     @property
     @dbconnection
diff --git a/src/mailman/model/mailinglist.py b/src/mailman/model/mailinglist.py
index 43cc26c6e..f8d1481a2 100644
--- a/src/mailman/model/mailinglist.py
+++ b/src/mailman/model/mailinglist.py
@@ -431,7 +431,7 @@ class MailingList(Model):
             ContentFilter.mailing_list == self,
             ContentFilter.filter_type == FilterType.pass_extension)
         for content_filter in results:
-            yield content_filter.pass_pattern
+            yield content_filter.filter_pattern
 
     @pass_extensions.setter
     @dbconnection
@@ -459,7 +459,7 @@ class MailingList(Model):
         elif role is MemberRole.nonmember:
             return self.nonmembers
         else:
-            raise TypeError('Undefined MemberRole: {}'.format(role))
+            raise ValueError('Undefined MemberRole: {}'.format(role))
 
     @dbconnection
     def subscribe(self, store, subscriber, role=MemberRole.member):
@@ -576,10 +576,10 @@ class ListArchiver(Model):
 
     @property
     def system_archiver(self):
-        for archiver in config.archivers:
+        for archiver in config.archivers:           # pragma: no branch
             if archiver.name == self.name:
                 return archiver
-        return None
+        raise AssertionError('Archiver not found: {}'.format(self.name))
 
     @property
     def is_enabled(self):
@@ -613,8 +613,7 @@ class ListArchiverSet:
     def archivers(self, store):
         entries = store.query(ListArchiver).filter(
             ListArchiver.mailing_list == self._mailing_list)
-        for entry in entries:
-            yield entry
+        yield from entries
 
     @dbconnection
     def get(self, store, archiver_name):
diff --git a/src/mailman/model/requests.py b/src/mailman/model/requests.py
index c7e61299c..831674aa1 100644
--- a/src/mailman/model/requests.py
+++ b/src/mailman/model/requests.py
@@ -83,8 +83,7 @@ class ListRequests:
     def held_requests(self, store):
         results = store.query(_Request).filter_by(
             mailing_list=self.mailing_list)
-        for request in results:
-            yield request
+        yield from results
 
     @dbconnection
     def of_type(self, store, request_type):
diff --git a/src/mailman/model/roster.py b/src/mailman/model/roster.py
index 9fbb8816b..6890debf4 100644
--- a/src/mailman/model/roster.py
+++ b/src/mailman/model/roster.py
@@ -68,8 +68,7 @@ class AbstractRoster:
     @property
     def members(self):
         """See `IRoster`."""
-        for member in self._query():
-            yield member
+        yield from self._query()
 
     @property
     def member_count(self):
@@ -84,9 +83,7 @@ class AbstractRoster:
         # keep a set of unique users.  It's possible for the same user to be
         # subscribed to a mailing list multiple times with different
         # addresses.
-        users = set(member.address.user for member in self.members)
-        for user in users:
-            yield user
+        yield from set(member.address.user for member in self.members)
 
     @property
     def addresses(self):
@@ -189,19 +186,12 @@ class AdministratorRoster(AbstractRoster):
     @dbconnection
     def get_member(self, store, email):
         """See `IRoster`."""
-        results = store.query(Member).filter(
+        return store.query(Member).filter(
             Member.list_id == self._mlist.list_id,
             or_(Member.role == MemberRole.moderator,
                 Member.role == MemberRole.owner),
             Address.email == email,
-            Member.address_id == Address.id)
-        if results.count() == 0:
-            return None
-        elif results.count() == 1:
-            return results[0]
-        else:
-            raise AssertionError(
-                'Too many matching member results: {0}'.format(results))
+            Member.address_id == Address.id).one_or_none()
 
 
 
@@ -243,8 +233,7 @@ class RegularMemberRoster(DeliveryMemberRoster):
     @property
     def members(self):
         """See `IRoster`."""
-        for member in self._get_members(DeliveryMode.regular):
-            yield member
+        yield from self._get_members(DeliveryMode.regular)
 
 
 
@@ -256,10 +245,10 @@ class DigestMemberRoster(DeliveryMemberRoster):
     @property
     def members(self):
         """See `IRoster`."""
-        for member in self._get_members(DeliveryMode.plaintext_digests,
-                                        DeliveryMode.mime_digests,
-                                        DeliveryMode.summary_digests):
-            yield member
+        yield from self._get_members(
+            DeliveryMode.plaintext_digests,
+            DeliveryMode.mime_digests,
+            DeliveryMode.summary_digests)
 
 
 
@@ -301,8 +290,7 @@ class Memberships:
     @property
     def members(self):
         """See `IRoster`."""
-        for member in self._query():
-            yield member
+        yield from self._query()
 
     @property
     def users(self):
@@ -312,27 +300,14 @@ class Memberships:
     @property
     def addresses(self):
         """See `IRoster`."""
-        for address in self._user.addresses:
-            yield address
+        yield from self._user.addresses
 
     @dbconnection
     def get_member(self, store, email):
         """See `IRoster`."""
-        results = store.query(Member).filter(
-            Member.address_id == Address.id,
-            Address.user_id == self._user.id)
-        if results.count() == 0:
-            return None
-        elif results.count() == 1:
-            return results[0]
-        else:
-            raise AssertionError(
-                'Too many matching member results: {0}'.format(
-                    results.count()))
+        raise NotImplementedError
 
     @dbconnection
     def get_memberships(self, store, address):
         """See `IRoster`."""
-        # 2015-04-14 BAW: See LP: #1444055 -- this currently exists just to
-        # pass a test.
         raise NotImplementedError
diff --git a/src/mailman/model/subscriptions.py b/src/mailman/model/subscriptions.py
index 93c7c97c2..b7276b2cd 100644
--- a/src/mailman/model/subscriptions.py
+++ b/src/mailman/model/subscriptions.py
@@ -82,7 +82,7 @@ class SubscriptionService:
         # which are controlled by the user, otherwise we'll just search for
         # the given address.
         if subscriber is None and list_id is None and role is None:
-            raise NoResultFound
+            return None
         order = (Member.list_id, Address.email, Member.role)
         # Querying for the subscriber is the most complicated part, because
         # the parameter can either be an email address or a user id.  Start by
@@ -116,24 +116,23 @@ class SubscriptionService:
 
     def find_members(self, subscriber=None, list_id=None, role=None):
         """See `ISubscriptionService`."""
-        try:
-            query = self._find_members(subscriber, list_id, role)
-        except NoResultFound:
-            query = None
-        return QuerySequence(query)
+        return QuerySequence(self._find_members(subscriber, list_id, role))
 
     def find_member(self, subscriber=None, list_id=None, role=None):
         """See `ISubscriptionService`."""
         try:
-            return self._find_members(subscriber, list_id, role).one()
+            result = self._find_members(subscriber, list_id, role)
+            return (result if result is None else result.one())
         except NoResultFound:
             return None
         except MultipleResultsFound:
+            # Coerce the exception into a Mailman-layer exception so call
+            # sites don't have to import from SQLAlchemy, resulting in a layer
+            # violation.
             raise TooManyMembersError(subscriber, list_id, role)
 
     def __iter__(self):
-        for member in self.get_members():
-            yield member
+        yield from self.get_members()
 
     def leave(self, list_id, email):
         """See `ISubscriptionService`."""
diff --git a/src/mailman/model/tests/test_mailinglist.py b/src/mailman/model/tests/test_mailinglist.py
index 17259621e..9e3708ee5 100644
--- a/src/mailman/model/tests/test_mailinglist.py
+++ b/src/mailman/model/tests/test_mailinglist.py
@@ -75,6 +75,17 @@ class TestMailingList(unittest.TestCase):
         self.assertRaises(MissingPreferredAddressError,
                           self._mlist.subscribe, anne)
 
+    def test_pass_extensions(self):
+        self._mlist.pass_extensions = ('foo', 'bar', 'baz')
+        self.assertEqual(list(self._mlist.pass_extensions),
+                         ['foo', 'bar', 'baz'])
+
+    def test_get_roster_argument(self):
+        self.assertRaises(ValueError, self._mlist.get_roster, 'members')
+
+    def test_subscribe_argument(self):
+        self.assertRaises(ValueError, self._mlist.subscribe, 'anne')
+
 
 
 class TestListArchiver(unittest.TestCase):
@@ -218,3 +229,11 @@ class TestHeaderMatch(unittest.TestCase):
              ('header', 'pattern', None),
              ('subject', 'patt.*', None),
              ])
+
+    def test_clear(self):
+        header_matches = IHeaderMatchSet(self._mlist)
+        header_matches.add('Header', 'pattern')
+        self.assertEqual(len(self._mlist.header_matches), 1)
+        with transaction():
+            header_matches.clear()
+        self.assertEqual(len(self._mlist.header_matches), 0)
diff --git a/src/mailman/model/tests/test_roster.py b/src/mailman/model/tests/test_roster.py
index 15e78b288..184c8c157 100644
--- a/src/mailman/model/tests/test_roster.py
+++ b/src/mailman/model/tests/test_roster.py
@@ -200,3 +200,9 @@ class TestMembershipsRoster(unittest.TestCase):
         self.assertEqual(
             [record.address.email for record in memberships],
             ['anne@example.com', 'anne@example.com'])
+
+    def test_memberships_users(self):
+        self._ant.subscribe(self._anne)
+        users = list(self._anne.memberships.users)
+        self.assertEqual(len(users), 1)
+        self.assertEqual(users[0], self._anne)
diff --git a/src/mailman/model/tests/test_subscriptions.py b/src/mailman/model/tests/test_subscriptions.py
index 3e97bd427..f389cff55 100644
--- a/src/mailman/model/tests/test_subscriptions.py
+++ b/src/mailman/model/tests/test_subscriptions.py
@@ -234,7 +234,7 @@ class TestSubscriptionService(unittest.TestCase):
              ('test3', 'anne3', MemberRole.moderator),
              ])
 
-    def test_find_members_shortcut(self):
+    def test_find_no_members(self):
         members = self._service.find_members()
         self.assertEqual(len(members), 0)
 
diff --git a/src/mailman/model/usermanager.py b/src/mailman/model/usermanager.py
index 93dd03e20..8b923f07e 100644
--- a/src/mailman/model/usermanager.py
+++ b/src/mailman/model/usermanager.py
@@ -103,8 +103,7 @@ class UserManager:
     @dbconnection
     def users(self, store):
         """See `IUserManager`."""
-        for user in store.query(User).all():
-            yield user
+        yield from store.query(User).all()
 
     @dbconnection
     def create_address(self, store, email, display_name=None):
@@ -152,19 +151,16 @@ class UserManager:
     @dbconnection
     def addresses(self, store):
         """See `IUserManager`."""
-        for address in store.query(Address).all():
-            yield address
+        yield from store.query(Address).all()
 
     @property
     @dbconnection
     def members(self, store):
         """See `IUserManager."""
-        for member in store.query(Member).all():
-            yield member
+        yield from store.query(Member).all()
 
     @property
     @dbconnection
     def server_owners(self, store):
         """ See `IUserManager."""
-        users = store.query(User).filter_by(is_server_owner=True)
-        yield from users
+        yield from store.query(User).filter_by(is_server_owner=True)
diff --git a/src/mailman/mta/aliases.py b/src/mailman/mta/aliases.py
index 768f8caac..ae7e70a7f 100644
--- a/src/mailman/mta/aliases.py
+++ b/src/mailman/mta/aliases.py
@@ -48,7 +48,7 @@ class MailTransportAgentAliases:
         # Always return
         yield mlist.posting_address
         for destination in sorted(SUBDESTINATIONS):
-            yield '{0}-{1}@{2}'.format(
+            yield '{}-{}@{}'.format(
                 mlist.list_name, destination, mlist.mail_host)
 
     def destinations(self, mlist):
@@ -56,4 +56,4 @@ class MailTransportAgentAliases:
         # Always return
         yield mlist.list_name
         for destination in sorted(SUBDESTINATIONS):
-            yield '{0}-{1}'.format(mlist.list_name, destination)
+            yield '{}-{}'.format(mlist.list_name, destination)
diff --git a/src/mailman/testing/helpers.py b/src/mailman/testing/helpers.py
index ea940dbcf..fa16c1f7f 100644
--- a/src/mailman/testing/helpers.py
+++ b/src/mailman/testing/helpers.py
@@ -220,8 +220,7 @@ class TestableMaster(Master):
     @property
     def runner_pids(self):
         """The pids of all the child runner processes."""
-        for pid in self._started_kids:
-            yield pid
+        yield from self._started_kids
 
 
 
diff --git a/src/mailman/testing/mta.py b/src/mailman/testing/mta.py
index a75e49237..9642803e2 100644
--- a/src/mailman/testing/mta.py
+++ b/src/mailman/testing/mta.py
@@ -251,8 +251,7 @@ class ConnectionCountingController(QueueController):
     @property
     def messages(self):
         """Return all the messages received by the SMTP server."""
-        for message in self:
-            yield message
+        yield from self
 
     def clear(self):
         """Clear all the messages from the queue."""
diff --git a/src/mailman/utilities/modules.py b/src/mailman/utilities/modules.py
index 3d9f45470..4a506321e 100644
--- a/src/mailman/utilities/modules.py
+++ b/src/mailman/utilities/modules.py
@@ -106,8 +106,7 @@ def find_components(package, interface):
         module = sys.modules[module_name]
         if not hasattr(module, '__all__'):
             continue
-        for component in scan_module(module, interface):
-            yield component
+        yield from scan_module(module, interface)