Merge branch 'develop' of github.com:matrix-org/synapse into neilj/fix_mau_init

.travis.yml

@@ -4,6 +4,13 @@ language: python
 # tell travis to cache ~/.cache/pip
 cache: pip
 
+# only build branches we care about (PRs are built seperately)
+branches:
+  only:
+    - master
+    - develop
+    - /^release-v/
+
 before_script:
   - git remote set-branches --add origin develop
   - git fetch origin develop

README.rst

@@ -174,6 +174,12 @@ Alternatively, Andreas Peters (previously Silvio Fricke) has contributed a
 Dockerfile to automate a synapse server in a single Docker image, at
 https://hub.docker.com/r/avhost/docker-matrix/tags/
 
+Slavi Pantaleev has created an Ansible playbook,
+which installs the offical Docker image of Matrix Synapse
+along with many other Matrix-related services (Postgres database, riot-web, coturn, mxisd, SSL support, etc.).
+For more details, see
+https://github.com/spantaleev/matrix-docker-ansible-deploy
+
 Configuring Synapse
 -------------------
 

changelog.d/3698.misc

@@ -0,0 +1 @@
+Add information about the [matrix-docker-ansible-deploy](https://github.com/spantaleev/matrix-docker-ansible-deploy) playbook

changelog.d/3786.misc

@@ -0,0 +1 @@
+Add initial implementation of new state resolution algorithm

changelog.d/3969.bugfix

@@ -0,0 +1 @@
+Fix HTTP error response codes for federated group requests.

changelog.d/4063.misc

@@ -0,0 +1 @@
+Refactor room alias creation code

changelog.d/4074.bugfix

@@ -0,0 +1 @@
+Correctly account for cpu usage by background threads

changelog.d/4075.misc

@@ -0,0 +1 @@
+Clean up threading and logcontexts in pushers

changelog.d/4077.misc

@@ -0,0 +1 @@
+Give some more things logcontexts

changelog.d/4082.misc

@@ -0,0 +1 @@
+Clean up some bits of code which were flagged by the linter

changelog.d/4083.bugfix

@@ -0,0 +1 @@
+Fix bug which prevented backslashes being used in event field filters

scripts-dev/tail-synapse.py

@@ -48,7 +48,7 @@ def main():
                 row.name: row.position
                 for row in replicate(server, {"streams": "-1"})["streams"].rows
             }
-        except requests.exceptions.ConnectionError as e:
+        except requests.exceptions.ConnectionError:
             time.sleep(0.1)
 
     while True:

scripts/synapse_port_db

@@ -501,7 +501,8 @@ class Porter(object):
 
             try:
                 yield self.postgres_store.runInteraction("alter_table", alter_table)
-            except Exception as e:
+            except Exception:
+                # On Error Resume Next
                 pass
 
             yield self.postgres_store.runInteraction(

setup.cfg

@@ -14,17 +14,16 @@ ignore =
     pylint.cfg
     tox.ini
 
-[pep8]
-max-line-length = 90
-#  W503 requires that binary operators be at the end, not start, of lines. Erik
-#  doesn't like it.  E203 is contrary to PEP8.  E731 is silly.
-ignore = W503,E203,E731
-
 [flake8]
-# note that flake8 inherits the "ignore" settings from "pep8" (because it uses
-# pep8 to do those checks), but not the "max-line-length" setting
 max-line-length = 90
-ignore=W503,E203,E731
+
+# see https://pycodestyle.readthedocs.io/en/latest/intro.html#error-codes
+# for error codes. The ones we ignore are:
+#  W503: line break before binary operator
+#  W504: line break after binary operator
+#  E203: whitespace before ':' (which is contrary to pep8?)
+#  E731: do not assign a lambda expression, use a def
+ignore=W503,W504,E203,E731
 
 [isort]
 line_length = 89

synapse/api/filtering.py

@@ -172,7 +172,10 @@ USER_FILTER_SCHEMA = {
                 # events a lot easier as we can then use a negative lookbehind
                 # assertion to split '\.' If we allowed \\ then it would
                 # incorrectly split '\\.' See synapse.events.utils.serialize_event
-                "pattern": "^((?!\\\).)*$"
+                #
+                # Note that because this is a regular expression, we have to escape
+                # each backslash in the pattern.
+                "pattern": r"^((?!\\\\).)*$"
             }
         }
     },

synapse/app/pusher.py

@@ -161,11 +161,11 @@ class PusherReplicationHandler(ReplicationClientHandler):
                     else:
                         yield self.start_pusher(row.user_id, row.app_id, row.pushkey)
             elif stream_name == "events":
-                self.pusher_pool.on_new_notifications(
+                yield self.pusher_pool.on_new_notifications(
                     token, token,
                 )
             elif stream_name == "receipts":
-                self.pusher_pool.on_new_receipts(
+                yield self.pusher_pool.on_new_receipts(
                     token, token, set(row.room_id for row in rows)
                 )
         except Exception:
@@ -183,7 +183,7 @@ class PusherReplicationHandler(ReplicationClientHandler):
     def start_pusher(self, user_id, app_id, pushkey):
         key = "%s:%s" % (app_id, pushkey)
         logger.info("Starting pusher %r / %r", user_id, key)
-        return self.pusher_pool._refresh_pusher(app_id, pushkey, user_id)
+        return self.pusher_pool.start_pusher_by_id(app_id, pushkey, user_id)
 
 
 def start(config_options):

synapse/config/repository.py

@@ -178,7 +178,7 @@ class ContentRepositoryConfig(Config):
     def default_config(self, **kwargs):
         media_store = self.default_path("media_store")
         uploads_path = self.default_path("uploads")
-        return """
+        return r"""
         # Directory where uploaded images and attachments are stored.
         media_store_path: "%(media_store)s"
 

synapse/crypto/keyclient.py

@@ -55,7 +55,7 @@ def fetch_server_key(server_name, tls_client_options_factory, path=KEY_API_V1):
                 raise IOError("Cannot get key for %r" % server_name)
         except (ConnectError, DomainError) as e:
             logger.warn("Error getting key for %r: %s", server_name, e)
-        except Exception as e:
+        except Exception:
             logger.exception("Error getting key for %r", server_name)
     raise IOError("Cannot get key for %r" % server_name)
 

synapse/event_auth.py

@@ -690,7 +690,7 @@ def auth_types_for_event(event):
     auth_types = []
 
     auth_types.append((EventTypes.PowerLevels, "", ))
-    auth_types.append((EventTypes.Member, event.user_id, ))
+    auth_types.append((EventTypes.Member, event.sender, ))
     auth_types.append((EventTypes.Create, "", ))
 
     if event.type == EventTypes.Member:

synapse/federation/federation_server.py

@@ -800,7 +800,7 @@ class FederationHandlerRegistry(object):
             yield handler(origin, content)
         except SynapseError as e:
             logger.info("Failed to handle edu %r: %r", edu_type, e)
-        except Exception as e:
+        except Exception:
             logger.exception("Failed to handle edu %r", edu_type)
 
     def on_query(self, query_type, args):

synapse/handlers/auth.py

@@ -22,7 +22,7 @@ import bcrypt
 import pymacaroons
 from canonicaljson import json
 
-from twisted.internet import defer, threads
+from twisted.internet import defer
 from twisted.web.client import PartialDownloadError
 
 import synapse.util.stringutils as stringutils
@@ -37,8 +37,8 @@ from synapse.api.errors import (
 )
 from synapse.module_api import ModuleApi
 from synapse.types import UserID
+from synapse.util import logcontext
 from synapse.util.caches.expiringcache import ExpiringCache
-from synapse.util.logcontext import make_deferred_yieldable
 
 from ._base import BaseHandler
 
@@ -884,11 +884,7 @@ class AuthHandler(BaseHandler):
                 bcrypt.gensalt(self.bcrypt_rounds),
             ).decode('ascii')
 
-        return make_deferred_yieldable(
+        return logcontext.defer_to_thread(self.hs.get_reactor(), _do_hash)
-            threads.deferToThreadPool(
-                self.hs.get_reactor(), self.hs.get_reactor().getThreadPool(), _do_hash
-            ),
-        )
 
     def validate_hash(self, password, stored_hash):
         """Validates that self.hash(password) == stored_hash.
@@ -913,13 +909,7 @@ class AuthHandler(BaseHandler):
             if not isinstance(stored_hash, bytes):
                 stored_hash = stored_hash.encode('ascii')
 
-            return make_deferred_yieldable(
+            return logcontext.defer_to_thread(self.hs.get_reactor(), _do_validate_hash)
-                threads.deferToThreadPool(
-                    self.hs.get_reactor(),
-                    self.hs.get_reactor().getThreadPool(),
-                    _do_validate_hash,
-                ),
-            )
         else:
             return defer.succeed(False)
 

synapse/handlers/deactivate_account.py

@@ -17,8 +17,8 @@ import logging
 from twisted.internet import defer
 
 from synapse.api.errors import SynapseError
+from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.types import UserID, create_requester
-from synapse.util.logcontext import run_in_background
 
 from ._base import BaseHandler
 
@@ -121,7 +121,7 @@ class DeactivateAccountHandler(BaseHandler):
             None
         """
         if not self._user_parter_running:
-            run_in_background(self._user_parter_loop)
+            run_as_background_process("user_parter_loop", self._user_parter_loop)
 
     @defer.inlineCallbacks
     def _user_parter_loop(self):

synapse/handlers/directory.py

@@ -80,12 +80,34 @@ class DirectoryHandler(BaseHandler):
         )
 
     @defer.inlineCallbacks
-    def create_association(self, user_id, room_alias, room_id, servers=None):
+    def create_association(self, requester, room_alias, room_id, servers=None,
-        # association creation for human users
+                           send_event=True):
-        # TODO(erikj): Do user auth.
+        """Attempt to create a new alias
 
-        if not self.spam_checker.user_may_create_room_alias(user_id, room_alias):
+        Args:
+            requester (Requester)
+            room_alias (RoomAlias)
+            room_id (str)
+            servers (list[str]|None): List of servers that others servers
+                should try and join via
+            send_event (bool): Whether to send an updated m.room.aliases event
+
+        Returns:
+            Deferred
+        """
+
+        user_id = requester.user.to_string()
+
+        service = requester.app_service
+        if service:
+            if not service.is_interested_in_alias(room_alias.to_string()):
                 raise SynapseError(
+                    400, "This application service has not reserved"
+                    " this kind of alias.", errcode=Codes.EXCLUSIVE
+                )
+        else:
+            if not self.spam_checker.user_may_create_room_alias(user_id, room_alias):
+                raise AuthError(
                     403, "This user is not permitted to create this alias",
                 )
 
@@ -94,28 +116,24 @@ class DirectoryHandler(BaseHandler):
                 user_id=user_id
             )
             if not can_create:
-            raise SynapseError(
+                raise AuthError(
                     400, "This alias is reserved by an application service.",
                     errcode=Codes.EXCLUSIVE
                 )
-        yield self._create_association(room_alias, room_id, servers, creator=user_id)
 
-    @defer.inlineCallbacks
+        yield self._create_association(room_alias, room_id, servers, creator=user_id)
-    def create_appservice_association(self, service, room_alias, room_id,
+        if send_event:
-                                      servers=None):
+            yield self.send_room_alias_update_event(
-        if not service.is_interested_in_alias(room_alias.to_string()):
+                requester,
-            raise SynapseError(
+                room_id
-                400, "This application service has not reserved"
-                " this kind of alias.", errcode=Codes.EXCLUSIVE
             )
 
-        # association creation for app services
-        yield self._create_association(room_alias, room_id, servers)
-
     @defer.inlineCallbacks
-    def delete_association(self, requester, user_id, room_alias):
+    def delete_association(self, requester, room_alias):
         # association deletion for human users
 
+        user_id = requester.user.to_string()
+
         try:
             can_delete = yield self._user_can_delete_alias(room_alias, user_id)
         except StoreError as e:
@@ -143,7 +161,6 @@ class DirectoryHandler(BaseHandler):
         try:
             yield self.send_room_alias_update_event(
                 requester,
-                requester.user.to_string(),
                 room_id
             )
 
@@ -261,7 +278,7 @@ class DirectoryHandler(BaseHandler):
             )
 
     @defer.inlineCallbacks
-    def send_room_alias_update_event(self, requester, user_id, room_id):
+    def send_room_alias_update_event(self, requester, room_id):
         aliases = yield self.store.get_aliases_for_room(room_id)
 
         yield self.event_creation_handler.create_and_send_nonmember_event(
@@ -270,7 +287,7 @@ class DirectoryHandler(BaseHandler):
                 "type": EventTypes.Aliases,
                 "state_key": self.hs.hostname,
                 "room_id": room_id,
-                "sender": user_id,
+                "sender": requester.user.to_string(),
                 "content": {"aliases": aliases},
             },
             ratelimit=False

synapse/handlers/federation.py

@@ -53,7 +53,7 @@ from synapse.replication.http.federation import (
     ReplicationFederationSendEventsRestServlet,
 )
 from synapse.replication.http.membership import ReplicationUserJoinedLeftRoomRestServlet
-from synapse.state import resolve_events_with_factory
+from synapse.state import StateResolutionStore, resolve_events_with_store
 from synapse.types import UserID, get_domain_from_id
 from synapse.util import logcontext, unwrapFirstError
 from synapse.util.async_helpers import Linearizer
@@ -384,24 +384,24 @@ class FederationHandler(BaseHandler):
                             for x in remote_state:
                                 event_map[x.event_id] = x
 
-                    # Resolve any conflicting state
-                    @defer.inlineCallbacks
-                    def fetch(ev_ids):
-                        fetched = yield self.store.get_events(
-                            ev_ids, get_prev_content=False, check_redacted=False,
-                        )
-                        # add any events we fetch here to the `event_map` so that we
-                        # can use them to build the state event list below.
-                        event_map.update(fetched)
-                        defer.returnValue(fetched)
-
                     room_version = yield self.store.get_room_version(room_id)
-                    state_map = yield resolve_events_with_factory(
+                    state_map = yield resolve_events_with_store(
-                        room_version, state_maps, event_map, fetch,
+                        room_version, state_maps, event_map,
+                        state_res_store=StateResolutionStore(self.store),
                     )
 
-                    # we need to give _process_received_pdu the actual state events
+                    # We need to give _process_received_pdu the actual state events
                     # rather than event ids, so generate that now.
+
+                    # First though we need to fetch all the events that are in
+                    # state_map, so we can build up the state below.
+                    evs = yield self.store.get_events(
+                        list(state_map.values()),
+                        get_prev_content=False,
+                        check_redacted=False,
+                    )
+                    event_map.update(evs)
+
                     state = [
                         event_map[e] for e in six.itervalues(state_map)
                     ]
@@ -2520,7 +2520,7 @@ class FederationHandler(BaseHandler):
 
             if not backfilled:  # Never notify for backfilled events
                 for event, _ in event_and_contexts:
-                    self._notify_persisted_event(event, max_stream_id)
+                    yield self._notify_persisted_event(event, max_stream_id)
 
     def _notify_persisted_event(self, event, max_stream_id):
         """Checks to see if notifier/pushers should be notified about the
@@ -2553,7 +2553,7 @@ class FederationHandler(BaseHandler):
             extra_users=extra_users
         )
 
-        self.pusher_pool.on_new_notifications(
+        return self.pusher_pool.on_new_notifications(
             event_stream_id, max_stream_id,
         )
 

synapse/handlers/groups_local.py

@@ -20,7 +20,7 @@ from six import iteritems
 
 from twisted.internet import defer
 
-from synapse.api.errors import SynapseError
+from synapse.api.errors import HttpResponseException, SynapseError
 from synapse.types import get_domain_from_id
 
 logger = logging.getLogger(__name__)
@@ -37,9 +37,23 @@ def _create_rerouter(func_name):
             )
         else:
             destination = get_domain_from_id(group_id)
-            return getattr(self.transport_client, func_name)(
+            d = getattr(self.transport_client, func_name)(
                 destination, group_id, *args, **kwargs
             )
+
+            # Capture errors returned by the remote homeserver and
+            # re-throw specific errors as SynapseErrors. This is so
+            # when the remote end responds with things like 403 Not
+            # In Group, we can communicate that to the client instead
+            # of a 500.
+            def h(failure):
+                failure.trap(HttpResponseException)
+                e = failure.value
+                if e.code == 403:
+                    raise e.to_synapse_error()
+                return failure
+            d.addErrback(h)
+            return d
     return f
 
 

synapse/handlers/message.py

@@ -779,7 +779,7 @@ class EventCreationHandler(object):
             event, context=context
         )
 
-        self.pusher_pool.on_new_notifications(
+        yield self.pusher_pool.on_new_notifications(
             event_stream_id, max_stream_id,
         )
 

synapse/handlers/receipts.py

@@ -119,7 +119,7 @@ class ReceiptsHandler(BaseHandler):
             "receipt_key", max_batch_id, rooms=affected_room_ids
         )
         # Note that the min here shouldn't be relied upon to be accurate.
-        self.hs.get_pusherpool().on_new_receipts(
+        yield self.hs.get_pusherpool().on_new_receipts(
             min_batch_id, max_batch_id, affected_room_ids,
         )
 

synapse/handlers/room.py

@@ -190,10 +190,11 @@ class RoomCreationHandler(BaseHandler):
         if room_alias:
             directory_handler = self.hs.get_handlers().directory_handler
             yield directory_handler.create_association(
-                user_id=user_id,
+                requester=requester,
                 room_id=room_id,
                 room_alias=room_alias,
                 servers=[self.hs.hostname],
+                send_event=False,
             )
 
         preset_config = config.get(
@@ -289,7 +290,7 @@ class RoomCreationHandler(BaseHandler):
         if room_alias:
             result["room_alias"] = room_alias.to_string()
             yield directory_handler.send_room_alias_update_event(
-                requester, user_id, room_id
+                requester, room_id
             )
 
         defer.returnValue(result)

synapse/handlers/user_directory.py

@@ -20,6 +20,7 @@ from six import iteritems
 from twisted.internet import defer
 
 from synapse.api.constants import EventTypes, JoinRules, Membership
+from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.storage.roommember import ProfileInfo
 from synapse.types import get_localpart_from_id
 from synapse.util.metrics import Measure
@@ -98,7 +99,6 @@ class UserDirectoryHandler(object):
         """
         return self.store.search_user_dir(user_id, search_term, limit)
 
-    @defer.inlineCallbacks
     def notify_new_event(self):
         """Called when there may be more deltas to process
         """
@@ -108,12 +108,16 @@ class UserDirectoryHandler(object):
         if self._is_processing:
             return
 
-        self._is_processing = True
+        @defer.inlineCallbacks
+        def process():
             try:
                 yield self._unsafe_process()
             finally:
                 self._is_processing = False
 
+        self._is_processing = True
+        run_as_background_process("user_directory.notify_new_event", process)
+
     @defer.inlineCallbacks
     def handle_local_profile_change(self, user_id, profile):
         """Called to update index of our local user profiles when they change

synapse/http/matrixfederationclient.py

@@ -230,7 +230,7 @@ class MatrixFederationHttpClient(object):
         Returns:
             Deferred: resolves with the http response object on success.
 
-            Fails with ``HTTPRequestException``: if we get an HTTP response
+            Fails with ``HttpResponseException``: if we get an HTTP response
                 code >= 300.
 
             Fails with ``NotRetryingDestination`` if we are not yet ready
@@ -480,7 +480,7 @@ class MatrixFederationHttpClient(object):
             Deferred: Succeeds when we get a 2xx HTTP response. The result
             will be the decoded JSON body.
 
-            Fails with ``HTTPRequestException`` if we get an HTTP response
+            Fails with ``HttpResponseException`` if we get an HTTP response
             code >= 300.
 
             Fails with ``NotRetryingDestination`` if we are not yet ready
@@ -534,7 +534,7 @@ class MatrixFederationHttpClient(object):
             Deferred: Succeeds when we get a 2xx HTTP response. The result
             will be the decoded JSON body.
 
-            Fails with ``HTTPRequestException`` if we get an HTTP response
+            Fails with ``HttpResponseException`` if we get an HTTP response
             code >= 300.
 
             Fails with ``NotRetryingDestination`` if we are not yet ready
@@ -589,7 +589,7 @@ class MatrixFederationHttpClient(object):
             Deferred: Succeeds when we get a 2xx HTTP response. The result
             will be the decoded JSON body.
 
-            Fails with ``HTTPRequestException`` if we get an HTTP response
+            Fails with ``HttpResponseException`` if we get an HTTP response
             code >= 300.
 
             Fails with ``NotRetryingDestination`` if we are not yet ready
@@ -640,7 +640,7 @@ class MatrixFederationHttpClient(object):
             Deferred: Succeeds when we get a 2xx HTTP response. The result
             will be the decoded JSON body.
 
-            Fails with ``HTTPRequestException`` if we get an HTTP response
+            Fails with ``HttpResponseException`` if we get an HTTP response
             code >= 300.
 
             Fails with ``NotRetryingDestination`` if we are not yet ready
@@ -684,7 +684,7 @@ class MatrixFederationHttpClient(object):
             Deferred: resolves with an (int,dict) tuple of the file length and
             a dict of the response headers.
 
-            Fails with ``HTTPRequestException`` if we get an HTTP response code
+            Fails with ``HttpResponseException`` if we get an HTTP response code
             >= 300
 
             Fails with ``NotRetryingDestination`` if we are not yet ready

synapse/push/emailpusher.py

@@ -18,8 +18,7 @@ import logging
 from twisted.internet import defer
 from twisted.internet.error import AlreadyCalled, AlreadyCancelled
 
-from synapse.util.logcontext import LoggingContext
+from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.util.metrics import Measure
 
 logger = logging.getLogger(__name__)
 
@@ -71,18 +70,11 @@ class EmailPusher(object):
         # See httppusher
         self.max_stream_ordering = None
 
-        self.processing = False
+        self._is_processing = False
 
-    @defer.inlineCallbacks
     def on_started(self):
         if self.mailer is not None:
-            try:
+            self._start_processing()
-                self.throttle_params = yield self.store.get_throttle_params_by_room(
-                    self.pusher_id
-                )
-                yield self._process()
-            except Exception:
-                logger.exception("Error starting email pusher")
 
     def on_stop(self):
         if self.timed_call:
@@ -92,31 +84,40 @@ class EmailPusher(object):
                 pass
             self.timed_call = None
 
-    @defer.inlineCallbacks
     def on_new_notifications(self, min_stream_ordering, max_stream_ordering):
         self.max_stream_ordering = max(max_stream_ordering, self.max_stream_ordering)
-        yield self._process()
+        self._start_processing()
 
     def on_new_receipts(self, min_stream_id, max_stream_id):
         # We could wake up and cancel the timer but there tend to be quite a
         # lot of read receipts so it's probably less work to just let the
         # timer fire
-        return defer.succeed(None)
+        pass
 
-    @defer.inlineCallbacks
     def on_timer(self):
         self.timed_call = None
-        yield self._process()
+        self._start_processing()
+
+    def _start_processing(self):
+        if self._is_processing:
+            return
+
+        run_as_background_process("emailpush.process", self._process)
 
     @defer.inlineCallbacks
     def _process(self):
-        if self.processing:
+        # we should never get here if we are already processing
-            return
+        assert not self._is_processing
 
-        with LoggingContext("emailpush._process"):
-            with Measure(self.clock, "emailpush._process"):
         try:
-                    self.processing = True
+            self._is_processing = True
+
+            if self.throttle_params is None:
+                # this is our first loop: load up the throttle params
+                self.throttle_params = yield self.store.get_throttle_params_by_room(
+                    self.pusher_id
+                )
+
             # if the max ordering changes while we're running _unsafe_process,
             # call it again, and so on until we've caught up.
             while True:
@@ -128,7 +129,7 @@ class EmailPusher(object):
                 if self.max_stream_ordering == starting_max_ordering:
                     break
         finally:
-                    self.processing = False
+            self._is_processing = False
 
     @defer.inlineCallbacks
     def _unsafe_process(self):

synapse/push/httppusher.py

@@ -22,9 +22,8 @@ from prometheus_client import Counter
 from twisted.internet import defer
 from twisted.internet.error import AlreadyCalled, AlreadyCancelled
 
+from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.push import PusherConfigException
-from synapse.util.logcontext import LoggingContext
-from synapse.util.metrics import Measure
 
 from . import push_rule_evaluator, push_tools
 
@@ -61,7 +60,7 @@ class HttpPusher(object):
         self.backoff_delay = HttpPusher.INITIAL_BACKOFF_SEC
         self.failing_since = pusherdict['failing_since']
         self.timed_call = None
-        self.processing = False
+        self._is_processing = False
 
         # This is the highest stream ordering we know it's safe to process.
         # When new events arrive, we'll be given a window of new events: we
@@ -92,34 +91,27 @@ class HttpPusher(object):
         self.data_minus_url.update(self.data)
         del self.data_minus_url['url']
 
-    @defer.inlineCallbacks
     def on_started(self):
-        try:
+        self._start_processing()
-            yield self._process()
-        except Exception:
-            logger.exception("Error starting http pusher")
 
-    @defer.inlineCallbacks
     def on_new_notifications(self, min_stream_ordering, max_stream_ordering):
         self.max_stream_ordering = max(max_stream_ordering, self.max_stream_ordering or 0)
-        yield self._process()
+        self._start_processing()
 
-    @defer.inlineCallbacks
     def on_new_receipts(self, min_stream_id, max_stream_id):
         # Note that the min here shouldn't be relied upon to be accurate.
 
         # We could check the receipts are actually m.read receipts here,
         # but currently that's the only type of receipt anyway...
-        with LoggingContext("push.on_new_receipts"):
+        run_as_background_process("http_pusher.on_new_receipts", self._update_badge)
-            with Measure(self.clock, "push.on_new_receipts"):
-                badge = yield push_tools.get_badge_count(
-                    self.hs.get_datastore(), self.user_id
-                )
-            yield self._send_badge(badge)
 
     @defer.inlineCallbacks
+    def _update_badge(self):
+        badge = yield push_tools.get_badge_count(self.hs.get_datastore(), self.user_id)
+        yield self._send_badge(badge)
+
     def on_timer(self):
-        yield self._process()
+        self._start_processing()
 
     def on_stop(self):
         if self.timed_call:
@@ -129,15 +121,19 @@ class HttpPusher(object):
                 pass
             self.timed_call = None
 
-    @defer.inlineCallbacks
+    def _start_processing(self):
-    def _process(self):
+        if self._is_processing:
-        if self.processing:
             return
 
-        with LoggingContext("push._process"):
+        run_as_background_process("httppush.process", self._process)
-            with Measure(self.clock, "push._process"):
+
+    @defer.inlineCallbacks
+    def _process(self):
+        # we should never get here if we are already processing
+        assert not self._is_processing
+
         try:
-                    self.processing = True
+            self._is_processing = True
             # if the max ordering changes while we're running _unsafe_process,
             # call it again, and so on until we've caught up.
             while True:
@@ -149,7 +145,7 @@ class HttpPusher(object):
                 if self.max_stream_ordering == starting_max_ordering:
                     break
         finally:
-                    self.processing = False
+            self._is_processing = False
 
     @defer.inlineCallbacks
     def _unsafe_process(self):

synapse/push/pusherpool.py

@@ -20,24 +20,39 @@ from twisted.internet import defer
 
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.push.pusher import PusherFactory
-from synapse.util.logcontext import make_deferred_yieldable, run_in_background
 
 logger = logging.getLogger(__name__)
 
 
 class PusherPool:
+    """
+    The pusher pool. This is responsible for dispatching notifications of new events to
+    the http and email pushers.
+
+    It provides three methods which are designed to be called by the rest of the
+    application: `start`, `on_new_notifications`, and `on_new_receipts`: each of these
+    delegates to each of the relevant pushers.
+
+    Note that it is expected that each pusher will have its own 'processing' loop which
+    will send out the notifications in the background, rather than blocking until the
+    notifications are sent; accordingly Pusher.on_started, Pusher.on_new_notifications and
+    Pusher.on_new_receipts are not expected to return deferreds.
+    """
     def __init__(self, _hs):
         self.hs = _hs
         self.pusher_factory = PusherFactory(_hs)
-        self.start_pushers = _hs.config.start_pushers
+        self._should_start_pushers = _hs.config.start_pushers
         self.store = self.hs.get_datastore()
         self.clock = self.hs.get_clock()
         self.pushers = {}
 
-    @defer.inlineCallbacks
     def start(self):
-        pushers = yield self.store.get_all_pushers()
+        """Starts the pushers off in a background process.
-        self._start_pushers(pushers)
+        """
+        if not self._should_start_pushers:
+            logger.info("Not starting pushers because they are disabled in the config")
+            return
+        run_as_background_process("start_pushers", self._start_pushers)
 
     @defer.inlineCallbacks
     def add_pusher(self, user_id, access_token, kind, app_id,
@@ -86,7 +101,7 @@ class PusherPool:
             last_stream_ordering=last_stream_ordering,
             profile_tag=profile_tag,
         )
-        yield self._refresh_pusher(app_id, pushkey, user_id)
+        yield self.start_pusher_by_id(app_id, pushkey, user_id)
 
     @defer.inlineCallbacks
     def remove_pushers_by_app_id_and_pushkey_not_user(self, app_id, pushkey,
@@ -123,45 +138,23 @@ class PusherPool:
                     p['app_id'], p['pushkey'], p['user_name'],
                 )
 
-    def on_new_notifications(self, min_stream_id, max_stream_id):
-        run_as_background_process(
-            "on_new_notifications",
-            self._on_new_notifications, min_stream_id, max_stream_id,
-        )
-
     @defer.inlineCallbacks
-    def _on_new_notifications(self, min_stream_id, max_stream_id):
+    def on_new_notifications(self, min_stream_id, max_stream_id):
         try:
             users_affected = yield self.store.get_push_action_users_in_range(
                 min_stream_id, max_stream_id
             )
 
-            deferreds = []
-
             for u in users_affected:
                 if u in self.pushers:
                     for p in self.pushers[u].values():
-                        deferreds.append(
+                        p.on_new_notifications(min_stream_id, max_stream_id)
-                            run_in_background(
-                                p.on_new_notifications,
-                                min_stream_id, max_stream_id,
-                            )
-                        )
 
-            yield make_deferred_yieldable(
-                defer.gatherResults(deferreds, consumeErrors=True),
-            )
         except Exception:
             logger.exception("Exception in pusher on_new_notifications")
 
-    def on_new_receipts(self, min_stream_id, max_stream_id, affected_room_ids):
-        run_as_background_process(
-            "on_new_receipts",
-            self._on_new_receipts, min_stream_id, max_stream_id, affected_room_ids,
-        )
-
     @defer.inlineCallbacks
-    def _on_new_receipts(self, min_stream_id, max_stream_id, affected_room_ids):
+    def on_new_receipts(self, min_stream_id, max_stream_id, affected_room_ids):
         try:
             # Need to subtract 1 from the minimum because the lower bound here
             # is not inclusive
@@ -171,26 +164,20 @@ class PusherPool:
             # This returns a tuple, user_id is at index 3
             users_affected = set([r[3] for r in updated_receipts])
 
-            deferreds = []
-
             for u in users_affected:
                 if u in self.pushers:
                     for p in self.pushers[u].values():
-                        deferreds.append(
+                        p.on_new_receipts(min_stream_id, max_stream_id)
-                            run_in_background(
-                                p.on_new_receipts,
-                                min_stream_id, max_stream_id,
-                            )
-                        )
 
-            yield make_deferred_yieldable(
-                defer.gatherResults(deferreds, consumeErrors=True),
-            )
         except Exception:
             logger.exception("Exception in pusher on_new_receipts")
 
     @defer.inlineCallbacks
-    def _refresh_pusher(self, app_id, pushkey, user_id):
+    def start_pusher_by_id(self, app_id, pushkey, user_id):
+        """Look up the details for the given pusher, and start it"""
+        if not self._should_start_pushers:
+            return
+
         resultlist = yield self.store.get_pushers_by_app_id_and_pushkey(
             app_id, pushkey
         )
@@ -201,21 +188,39 @@ class PusherPool:
                 p = r
 
         if p:
+            self._start_pusher(p)
 
-            self._start_pushers([p])
+    @defer.inlineCallbacks
+    def _start_pushers(self):
+        """Start all the pushers
 
-    def _start_pushers(self, pushers):
+        Returns:
-        if not self.start_pushers:
+            Deferred
-            logger.info("Not starting pushers because they are disabled in the config")
+        """
-            return
+        pushers = yield self.store.get_all_pushers()
         logger.info("Starting %d pushers", len(pushers))
         for pusherdict in pushers:
+            self._start_pusher(pusherdict)
+        logger.info("Started pushers")
+
+    def _start_pusher(self, pusherdict):
+        """Start the given pusher
+
+        Args:
+            pusherdict (dict):
+
+        Returns:
+            None
+        """
         try:
             p = self.pusher_factory.create_pusher(pusherdict)
         except Exception:
             logger.exception("Couldn't start a pusher: caught Exception")
-                continue
+            return
-            if p:
+
+        if not p:
+            return
+
         appid_pushkey = "%s:%s" % (
             pusherdict['app_id'],
             pusherdict['pushkey'],
@@ -225,9 +230,7 @@ class PusherPool:
         if appid_pushkey in byuser:
             byuser[appid_pushkey].on_stop()
         byuser[appid_pushkey] = p
-                run_in_background(p.on_started)
+        p.on_started()
-
-        logger.info("Started pushers")
 
     @defer.inlineCallbacks
     def remove_pusher(self, app_id, pushkey, user_id):

synapse/rest/client/v1/directory.py

@@ -74,37 +74,10 @@ class ClientDirectoryServer(ClientV1RestServlet):
         if room is None:
             raise SynapseError(400, "Room does not exist")
 
-        dir_handler = self.handlers.directory_handler
-
-        try:
-            # try to auth as a user
         requester = yield self.auth.get_user_by_req(request)
-            try:
+
-                user_id = requester.user.to_string()
+        yield self.handlers.directory_handler.create_association(
-                yield dir_handler.create_association(
+            requester, room_alias, room_id, servers
-                    user_id, room_alias, room_id, servers
-                )
-                yield dir_handler.send_room_alias_update_event(
-                    requester,
-                    user_id,
-                    room_id
-                )
-            except SynapseError as e:
-                raise e
-            except Exception:
-                logger.exception("Failed to create association")
-                raise
-        except AuthError:
-            # try to auth as an application service
-            service = yield self.auth.get_appservice_by_req(request)
-            yield dir_handler.create_appservice_association(
-                service, room_alias, room_id, servers
-            )
-            logger.info(
-                "Application service at %s created alias %s pointing to %s",
-                service.url,
-                room_alias.to_string(),
-                room_id
         )
 
         defer.returnValue((200, {}))
@@ -135,7 +108,7 @@ class ClientDirectoryServer(ClientV1RestServlet):
         room_alias = RoomAlias.from_string(room_alias)
 
         yield dir_handler.delete_association(
-            requester, user.to_string(), room_alias
+            requester, room_alias
         )
 
         logger.info(

synapse/rest/client/v2_alpha/auth.py

@@ -99,7 +99,7 @@ class AuthRestServlet(RestServlet):
     cannot be handled in the normal flow (with requests to the same endpoint).
     Current use is for web fallback auth.
     """
-    PATTERNS = client_v2_patterns("/auth/(?P<stagetype>[\w\.]*)/fallback/web")
+    PATTERNS = client_v2_patterns(r"/auth/(?P<stagetype>[\w\.]*)/fallback/web")
 
     def __init__(self, hs):
         super(AuthRestServlet, self).__init__()

synapse/rest/media/v1/media_repository.py

@@ -25,7 +25,7 @@ from six.moves.urllib import parse as urlparse
 
 import twisted.internet.error
 import twisted.web.http
-from twisted.internet import defer, threads
+from twisted.internet import defer
 from twisted.web.resource import Resource
 
 from synapse.api.errors import (
@@ -36,8 +36,8 @@ from synapse.api.errors import (
 )
 from synapse.http.matrixfederationclient import MatrixFederationHttpClient
 from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.util import logcontext
 from synapse.util.async_helpers import Linearizer
-from synapse.util.logcontext import make_deferred_yieldable
 from synapse.util.retryutils import NotRetryingDestination
 from synapse.util.stringutils import is_ascii, random_string
 
@@ -492,10 +492,11 @@ class MediaRepository(object):
         ))
 
         thumbnailer = Thumbnailer(input_path)
-        t_byte_source = yield make_deferred_yieldable(threads.deferToThread(
+        t_byte_source = yield logcontext.defer_to_thread(
+            self.hs.get_reactor(),
             self._generate_thumbnail,
             thumbnailer, t_width, t_height, t_method, t_type
-        ))
+        )
 
         if t_byte_source:
             try:
@@ -534,10 +535,11 @@ class MediaRepository(object):
         ))
 
         thumbnailer = Thumbnailer(input_path)
-        t_byte_source = yield make_deferred_yieldable(threads.deferToThread(
+        t_byte_source = yield logcontext.defer_to_thread(
+            self.hs.get_reactor(),
             self._generate_thumbnail,
             thumbnailer, t_width, t_height, t_method, t_type
-        ))
+        )
 
         if t_byte_source:
             try:
@@ -620,15 +622,17 @@ class MediaRepository(object):
         for (t_width, t_height, t_type), t_method in iteritems(thumbnails):
             # Generate the thumbnail
             if t_method == "crop":
-                t_byte_source = yield make_deferred_yieldable(threads.deferToThread(
+                t_byte_source = yield logcontext.defer_to_thread(
+                    self.hs.get_reactor(),
                     thumbnailer.crop,
                     t_width, t_height, t_type,
-                ))
+                )
             elif t_method == "scale":
-                t_byte_source = yield make_deferred_yieldable(threads.deferToThread(
+                t_byte_source = yield logcontext.defer_to_thread(
+                    self.hs.get_reactor(),
                     thumbnailer.scale,
                     t_width, t_height, t_type,
-                ))
+                )
             else:
                 logger.error("Unrecognized method: %r", t_method)
                 continue

synapse/rest/media/v1/media_storage.py

@@ -21,9 +21,10 @@ import sys
 
 import six
 
-from twisted.internet import defer, threads
+from twisted.internet import defer
 from twisted.protocols.basic import FileSender
 
+from synapse.util import logcontext
 from synapse.util.file_consumer import BackgroundFileConsumer
 from synapse.util.logcontext import make_deferred_yieldable
 
@@ -64,9 +65,10 @@ class MediaStorage(object):
 
         with self.store_into_file(file_info) as (f, fname, finish_cb):
             # Write to the main repository
-            yield make_deferred_yieldable(threads.deferToThread(
+            yield logcontext.defer_to_thread(
+                self.hs.get_reactor(),
                 _write_file_synchronously, source, f,
-            ))
+            )
             yield finish_cb()
 
         defer.returnValue(fname)

synapse/rest/media/v1/preview_url_resource.py

@@ -674,7 +674,7 @@ def summarize_paragraphs(text_nodes, min_size=200, max_size=500):
         # This splits the paragraph into words, but keeping the
         # (preceeding) whitespace intact so we can easily concat
         # words back together.
-        for match in re.finditer("\s*\S+", description):
+        for match in re.finditer(r"\s*\S+", description):
             word = match.group()
 
             # Keep adding words while the total length is less than

synapse/rest/media/v1/storage_provider.py

@@ -17,9 +17,10 @@ import logging
 import os
 import shutil
 
-from twisted.internet import defer, threads
+from twisted.internet import defer
 
 from synapse.config._base import Config
+from synapse.util import logcontext
 from synapse.util.logcontext import run_in_background
 
 from .media_storage import FileResponder
@@ -120,7 +121,8 @@ class FileStorageProviderBackend(StorageProvider):
         if not os.path.exists(dirname):
             os.makedirs(dirname)
 
-        return threads.deferToThread(
+        return logcontext.defer_to_thread(
+            self.hs.get_reactor(),
             shutil.copyfile, primary_fname, backup_fname,
         )
 

synapse/state/__init__.py

@@ -19,13 +19,14 @@ from collections import namedtuple
 
 from six import iteritems, itervalues
 
+import attr
 from frozendict import frozendict
 
 from twisted.internet import defer
 
 from synapse.api.constants import EventTypes, RoomVersions
 from synapse.events.snapshot import EventContext
-from synapse.state import v1
+from synapse.state import v1, v2
 from synapse.util.async_helpers import Linearizer
 from synapse.util.caches import get_cache_factor_for
 from synapse.util.caches.expiringcache import ExpiringCache
@@ -372,15 +373,10 @@ class StateHandler(object):
 
         result = yield self._state_resolution_handler.resolve_state_groups(
             room_id, room_version, state_groups_ids, None,
-            self._state_map_factory,
+            state_res_store=StateResolutionStore(self.store),
         )
         defer.returnValue(result)
 
-    def _state_map_factory(self, ev_ids):
-        return self.store.get_events(
-            ev_ids, get_prev_content=False, check_redacted=False,
-        )
-
     @defer.inlineCallbacks
     def resolve_events(self, room_version, state_sets, event):
         logger.info(
@@ -398,10 +394,10 @@ class StateHandler(object):
         }
 
         with Measure(self.clock, "state._resolve_events"):
-            new_state = yield resolve_events_with_factory(
+            new_state = yield resolve_events_with_store(
                 room_version, state_set_ids,
                 event_map=state_map,
-                state_map_factory=self._state_map_factory
+                state_res_store=StateResolutionStore(self.store),
             )
 
         new_state = {
@@ -436,7 +432,7 @@ class StateResolutionHandler(object):
     @defer.inlineCallbacks
     @log_function
     def resolve_state_groups(
-        self, room_id, room_version, state_groups_ids, event_map, state_map_factory,
+        self, room_id, room_version, state_groups_ids, event_map, state_res_store,
     ):
         """Resolves conflicts between a set of state groups
 
@@ -454,9 +450,11 @@ class StateResolutionHandler(object):
                 a dict from event_id to event, for any events that we happen to
                 have in flight (eg, those currently being persisted). This will be
                 used as a starting point fof finding the state we need; any missing
-                events will be requested via state_map_factory.
+                events will be requested via state_res_store.
 
-                If None, all events will be fetched via state_map_factory.
+                If None, all events will be fetched via state_res_store.
+
+            state_res_store (StateResolutionStore)
 
         Returns:
             Deferred[_StateCacheEntry]: resolved state
@@ -480,10 +478,10 @@ class StateResolutionHandler(object):
 
             # start by assuming we won't have any conflicted state, and build up the new
             # state map by iterating through the state groups. If we discover a conflict,
-            # we give up and instead use `resolve_events_with_factory`.
+            # we give up and instead use `resolve_events_with_store`.
             #
             # XXX: is this actually worthwhile, or should we just let
-            # resolve_events_with_factory do it?
+            # resolve_events_with_store do it?
             new_state = {}
             conflicted_state = False
             for st in itervalues(state_groups_ids):
@@ -498,11 +496,11 @@ class StateResolutionHandler(object):
             if conflicted_state:
                 logger.info("Resolving conflicted state for %r", room_id)
                 with Measure(self.clock, "state._resolve_events"):
-                    new_state = yield resolve_events_with_factory(
+                    new_state = yield resolve_events_with_store(
                         room_version,
                         list(itervalues(state_groups_ids)),
                         event_map=event_map,
-                        state_map_factory=state_map_factory,
+                        state_res_store=state_res_store,
                     )
 
             # if the new state matches any of the input state groups, we can
@@ -583,7 +581,7 @@ def _make_state_cache_entry(
     )
 
 
-def resolve_events_with_factory(room_version, state_sets, event_map, state_map_factory):
+def resolve_events_with_store(room_version, state_sets, event_map, state_res_store):
     """
     Args:
         room_version(str): Version of the room
@@ -599,17 +597,19 @@ def resolve_events_with_factory(room_version, state_sets, event_map, state_map_f
 
             If None, all events will be fetched via state_map_factory.
 
-        state_map_factory(func): will be called
+        state_res_store (StateResolutionStore)
-            with a list of event_ids that are needed, and should return with
-            a Deferred of dict of event_id to event.
 
     Returns
         Deferred[dict[(str, str), str]]:
             a map from (type, state_key) to event_id.
     """
-    if room_version in (RoomVersions.V1, RoomVersions.VDH_TEST,):
+    if room_version == RoomVersions.V1:
-        return v1.resolve_events_with_factory(
+        return v1.resolve_events_with_store(
-            state_sets, event_map, state_map_factory,
+            state_sets, event_map, state_res_store.get_events,
+        )
+    elif room_version == RoomVersions.VDH_TEST:
+        return v2.resolve_events_with_store(
+            state_sets, event_map, state_res_store,
         )
     else:
         # This should only happen if we added a version but forgot to add it to
@@ -617,3 +617,54 @@ def resolve_events_with_factory(room_version, state_sets, event_map, state_map_f
         raise Exception(
             "No state resolution algorithm defined for version %r" % (room_version,)
         )
+
+
+@attr.s
+class StateResolutionStore(object):
+    """Interface that allows state resolution algorithms to access the database
+    in well defined way.
+
+    Args:
+        store (DataStore)
+    """
+
+    store = attr.ib()
+
+    def get_events(self, event_ids, allow_rejected=False):
+        """Get events from the database
+
+        Args:
+            event_ids (list): The event_ids of the events to fetch
+            allow_rejected (bool): If True return rejected events.
+
+        Returns:
+            Deferred[dict[str, FrozenEvent]]: Dict from event_id to event.
+        """
+
+        return self.store.get_events(
+            event_ids,
+            check_redacted=False,
+            get_prev_content=False,
+            allow_rejected=allow_rejected,
+        )
+
+    def get_auth_chain(self, event_ids):
+        """Gets the full auth chain for a set of events (including rejected
+        events).
+
+        Includes the given event IDs in the result.
+
+        Note that:
+            1. All events must be state events.
+            2. For v1 rooms this may not have the full auth chain in the
+               presence of rejected events
+
+        Args:
+            event_ids (list): The event IDs of the events to fetch the auth
+                chain for. Must be state events.
+
+        Returns:
+            Deferred[list[str]]: List of event IDs of the auth chain.
+        """
+
+        return self.store.get_auth_chain_ids(event_ids, include_given=True)

synapse/state/v1.py

@@ -31,7 +31,7 @@ POWER_KEY = (EventTypes.PowerLevels, "")
 
 
 @defer.inlineCallbacks
-def resolve_events_with_factory(state_sets, event_map, state_map_factory):
+def resolve_events_with_store(state_sets, event_map, state_map_factory):
     """
     Args:
         state_sets(list): List of dicts of (type, state_key) -> event_id,

synapse/state/v2.py

@@ -0,0 +1,544 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 New Vector Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import heapq
+import itertools
+import logging
+
+from six import iteritems, itervalues
+
+from twisted.internet import defer
+
+from synapse import event_auth
+from synapse.api.constants import EventTypes
+from synapse.api.errors import AuthError
+
+logger = logging.getLogger(__name__)
+
+
+@defer.inlineCallbacks
+def resolve_events_with_store(state_sets, event_map, state_res_store):
+    """Resolves the state using the v2 state resolution algorithm
+
+    Args:
+        state_sets(list): List of dicts of (type, state_key) -> event_id,
+            which are the different state groups to resolve.
+
+        event_map(dict[str,FrozenEvent]|None):
+            a dict from event_id to event, for any events that we happen to
+            have in flight (eg, those currently being persisted). This will be
+            used as a starting point fof finding the state we need; any missing
+            events will be requested via state_res_store.
+
+            If None, all events will be fetched via state_res_store.
+
+        state_res_store (StateResolutionStore)
+
+    Returns
+        Deferred[dict[(str, str), str]]:
+            a map from (type, state_key) to event_id.
+    """
+
+    logger.debug("Computing conflicted state")
+
+    # First split up the un/conflicted state
+    unconflicted_state, conflicted_state = _seperate(state_sets)
+
+    if not conflicted_state:
+        defer.returnValue(unconflicted_state)
+
+    logger.debug("%d conflicted state entries", len(conflicted_state))
+    logger.debug("Calculating auth chain difference")
+
+    # Also fetch all auth events that appear in only some of the state sets'
+    # auth chains.
+    auth_diff = yield _get_auth_chain_difference(
+        state_sets, event_map, state_res_store,
+    )
+
+    full_conflicted_set = set(itertools.chain(
+        itertools.chain.from_iterable(itervalues(conflicted_state)),
+        auth_diff,
+    ))
+
+    events = yield state_res_store.get_events([
+        eid for eid in full_conflicted_set
+        if eid not in event_map
+    ], allow_rejected=True)
+    event_map.update(events)
+
+    full_conflicted_set = set(eid for eid in full_conflicted_set if eid in event_map)
+
+    logger.debug("%d full_conflicted_set entries", len(full_conflicted_set))
+
+    # Get and sort all the power events (kicks/bans/etc)
+    power_events = (
+        eid for eid in full_conflicted_set
+        if _is_power_event(event_map[eid])
+    )
+
+    sorted_power_events = yield _reverse_topological_power_sort(
+        power_events,
+        event_map,
+        state_res_store,
+        full_conflicted_set,
+    )
+
+    logger.debug("sorted %d power events", len(sorted_power_events))
+
+    # Now sequentially auth each one
+    resolved_state = yield _iterative_auth_checks(
+        sorted_power_events, unconflicted_state, event_map,
+        state_res_store,
+    )
+
+    logger.debug("resolved power events")
+
+    # OK, so we've now resolved the power events. Now sort the remaining
+    # events using the mainline of the resolved power level.
+
+    leftover_events = [
+        ev_id
+        for ev_id in full_conflicted_set
+        if ev_id not in sorted_power_events
+    ]
+
+    logger.debug("sorting %d remaining events", len(leftover_events))
+
+    pl = resolved_state.get((EventTypes.PowerLevels, ""), None)
+    leftover_events = yield _mainline_sort(
+        leftover_events, pl, event_map, state_res_store,
+    )
+
+    logger.debug("resolving remaining events")
+
+    resolved_state = yield _iterative_auth_checks(
+        leftover_events, resolved_state, event_map,
+        state_res_store,
+    )
+
+    logger.debug("resolved")
+
+    # We make sure that unconflicted state always still applies.
+    resolved_state.update(unconflicted_state)
+
+    logger.debug("done")
+
+    defer.returnValue(resolved_state)
+
+
+@defer.inlineCallbacks
+def _get_power_level_for_sender(event_id, event_map, state_res_store):
+    """Return the power level of the sender of the given event according to
+    their auth events.
+
+    Args:
+        event_id (str)
+        event_map (dict[str,FrozenEvent])
+        state_res_store (StateResolutionStore)
+
+    Returns:
+        Deferred[int]
+    """
+    event = yield _get_event(event_id, event_map, state_res_store)
+
+    pl = None
+    for aid, _ in event.auth_events:
+        aev = yield _get_event(aid, event_map, state_res_store)
+        if (aev.type, aev.state_key) == (EventTypes.PowerLevels, ""):
+            pl = aev
+            break
+
+    if pl is None:
+        # Couldn't find power level. Check if they're the creator of the room
+        for aid, _ in event.auth_events:
+            aev = yield _get_event(aid, event_map, state_res_store)
+            if (aev.type, aev.state_key) == (EventTypes.Create, ""):
+                if aev.content.get("creator") == event.sender:
+                    defer.returnValue(100)
+                break
+        defer.returnValue(0)
+
+    level = pl.content.get("users", {}).get(event.sender)
+    if level is None:
+        level = pl.content.get("users_default", 0)
+
+    if level is None:
+        defer.returnValue(0)
+    else:
+        defer.returnValue(int(level))
+
+
+@defer.inlineCallbacks
+def _get_auth_chain_difference(state_sets, event_map, state_res_store):
+    """Compare the auth chains of each state set and return the set of events
+    that only appear in some but not all of the auth chains.
+
+    Args:
+        state_sets (list)
+        event_map (dict[str,FrozenEvent])
+        state_res_store (StateResolutionStore)
+
+    Returns:
+        Deferred[set[str]]: Set of event IDs
+    """
+    common = set(itervalues(state_sets[0])).intersection(
+        *(itervalues(s) for s in state_sets[1:])
+    )
+
+    auth_sets = []
+    for state_set in state_sets:
+        auth_ids = set(
+            eid
+            for key, eid in iteritems(state_set)
+            if (key[0] in (
+                EventTypes.Member,
+                EventTypes.ThirdPartyInvite,
+            ) or key in (
+                (EventTypes.PowerLevels, ''),
+                (EventTypes.Create, ''),
+                (EventTypes.JoinRules, ''),
+            )) and eid not in common
+        )
+
+        auth_chain = yield state_res_store.get_auth_chain(auth_ids)
+        auth_ids.update(auth_chain)
+
+        auth_sets.append(auth_ids)
+
+    intersection = set(auth_sets[0]).intersection(*auth_sets[1:])
+    union = set().union(*auth_sets)
+
+    defer.returnValue(union - intersection)
+
+
+def _seperate(state_sets):
+    """Return the unconflicted and conflicted state. This is different than in
+    the original algorithm, as this defines a key to be conflicted if one of
+    the state sets doesn't have that key.
+
+    Args:
+        state_sets (list)
+
+    Returns:
+        tuple[dict, dict]: A tuple of unconflicted and conflicted state. The
+        conflicted state dict is a map from type/state_key to set of event IDs
+    """
+    unconflicted_state = {}
+    conflicted_state = {}
+
+    for key in set(itertools.chain.from_iterable(state_sets)):
+        event_ids = set(state_set.get(key) for state_set in state_sets)
+        if len(event_ids) == 1:
+            unconflicted_state[key] = event_ids.pop()
+        else:
+            event_ids.discard(None)
+            conflicted_state[key] = event_ids
+
+    return unconflicted_state, conflicted_state
+
+
+def _is_power_event(event):
+    """Return whether or not the event is a "power event", as defined by the
+    v2 state resolution algorithm
+
+    Args:
+        event (FrozenEvent)
+
+    Returns:
+        boolean
+    """
+    if (event.type, event.state_key) in (
+        (EventTypes.PowerLevels, ""),
+        (EventTypes.JoinRules, ""),
+        (EventTypes.Create, ""),
+    ):
+        return True
+
+    if event.type == EventTypes.Member:
+        if event.membership in ('leave', 'ban'):
+            return event.sender != event.state_key
+
+    return False
+
+
+@defer.inlineCallbacks
+def _add_event_and_auth_chain_to_graph(graph, event_id, event_map,
+                                       state_res_store, auth_diff):
+    """Helper function for _reverse_topological_power_sort that add the event
+    and its auth chain (that is in the auth diff) to the graph
+
+    Args:
+        graph (dict[str, set[str]]): A map from event ID to the events auth
+            event IDs
+        event_id (str): Event to add to the graph
+        event_map (dict[str,FrozenEvent])
+        state_res_store (StateResolutionStore)
+        auth_diff (set[str]): Set of event IDs that are in the auth difference.
+    """
+
+    state = [event_id]
+    while state:
+        eid = state.pop()
+        graph.setdefault(eid, set())
+
+        event = yield _get_event(eid, event_map, state_res_store)
+        for aid, _ in event.auth_events:
+            if aid in auth_diff:
+                if aid not in graph:
+                    state.append(aid)
+
+                graph.setdefault(eid, set()).add(aid)
+
+
+@defer.inlineCallbacks
+def _reverse_topological_power_sort(event_ids, event_map, state_res_store, auth_diff):
+    """Returns a list of the event_ids sorted by reverse topological ordering,
+    and then by power level and origin_server_ts
+
+    Args:
+        event_ids (list[str]): The events to sort
+        event_map (dict[str,FrozenEvent])
+        state_res_store (StateResolutionStore)
+        auth_diff (set[str]): Set of event IDs that are in the auth difference.
+
+    Returns:
+        Deferred[list[str]]: The sorted list
+    """
+
+    graph = {}
+    for event_id in event_ids:
+        yield _add_event_and_auth_chain_to_graph(
+            graph, event_id, event_map, state_res_store, auth_diff,
+        )
+
+    event_to_pl = {}
+    for event_id in graph:
+        pl = yield _get_power_level_for_sender(event_id, event_map, state_res_store)
+        event_to_pl[event_id] = pl
+
+    def _get_power_order(event_id):
+        ev = event_map[event_id]
+        pl = event_to_pl[event_id]
+
+        return -pl, ev.origin_server_ts, event_id
+
+    # Note: graph is modified during the sort
+    it = lexicographical_topological_sort(
+        graph,
+        key=_get_power_order,
+    )
+    sorted_events = list(it)
+
+    defer.returnValue(sorted_events)
+
+
+@defer.inlineCallbacks
+def _iterative_auth_checks(event_ids, base_state, event_map, state_res_store):
+    """Sequentially apply auth checks to each event in given list, updating the
+    state as it goes along.
+
+    Args:
+        event_ids (list[str]): Ordered list of events to apply auth checks to
+        base_state (dict[tuple[str, str], str]): The set of state to start with
+        event_map (dict[str,FrozenEvent])
+        state_res_store (StateResolutionStore)
+
+    Returns:
+        Deferred[dict[tuple[str, str], str]]: Returns the final updated state
+    """
+    resolved_state = base_state.copy()
+
+    for event_id in event_ids:
+        event = event_map[event_id]
+
+        auth_events = {}
+        for aid, _ in event.auth_events:
+            ev = yield _get_event(aid, event_map, state_res_store)
+
+            if ev.rejected_reason is None:
+                auth_events[(ev.type, ev.state_key)] = ev
+
+        for key in event_auth.auth_types_for_event(event):
+            if key in resolved_state:
+                ev_id = resolved_state[key]
+                ev = yield _get_event(ev_id, event_map, state_res_store)
+
+                if ev.rejected_reason is None:
+                    auth_events[key] = event_map[ev_id]
+
+        try:
+            event_auth.check(
+                event, auth_events,
+                do_sig_check=False,
+                do_size_check=False
+            )
+
+            resolved_state[(event.type, event.state_key)] = event_id
+        except AuthError:
+            pass
+
+    defer.returnValue(resolved_state)
+
+
+@defer.inlineCallbacks
+def _mainline_sort(event_ids, resolved_power_event_id, event_map,
+                   state_res_store):
+    """Returns a sorted list of event_ids sorted by mainline ordering based on
+    the given event resolved_power_event_id
+
+    Args:
+        event_ids (list[str]): Events to sort
+        resolved_power_event_id (str): The final resolved power level event ID
+        event_map (dict[str,FrozenEvent])
+        state_res_store (StateResolutionStore)
+
+    Returns:
+        Deferred[list[str]]: The sorted list
+    """
+    mainline = []
+    pl = resolved_power_event_id
+    while pl:
+        mainline.append(pl)
+        pl_ev = yield _get_event(pl, event_map, state_res_store)
+        auth_events = pl_ev.auth_events
+        pl = None
+        for aid, _ in auth_events:
+            ev = yield _get_event(aid, event_map, state_res_store)
+            if (ev.type, ev.state_key) == (EventTypes.PowerLevels, ""):
+                pl = aid
+                break
+
+    mainline_map = {ev_id: i + 1 for i, ev_id in enumerate(reversed(mainline))}
+
+    event_ids = list(event_ids)
+
+    order_map = {}
+    for ev_id in event_ids:
+        depth = yield _get_mainline_depth_for_event(
+            event_map[ev_id], mainline_map,
+            event_map, state_res_store,
+        )
+        order_map[ev_id] = (depth, event_map[ev_id].origin_server_ts, ev_id)
+
+    event_ids.sort(key=lambda ev_id: order_map[ev_id])
+
+    defer.returnValue(event_ids)
+
+
+@defer.inlineCallbacks
+def _get_mainline_depth_for_event(event, mainline_map, event_map, state_res_store):
+    """Get the mainline depths for the given event based on the mainline map
+
+    Args:
+        event (FrozenEvent)
+        mainline_map (dict[str, int]): Map from event_id to mainline depth for
+            events in the mainline.
+        event_map (dict[str,FrozenEvent])
+        state_res_store (StateResolutionStore)
+
+    Returns:
+        Deferred[int]
+    """
+
+    # We do an iterative search, replacing `event with the power level in its
+    # auth events (if any)
+    while event:
+        depth = mainline_map.get(event.event_id)
+        if depth is not None:
+            defer.returnValue(depth)
+
+        auth_events = event.auth_events
+        event = None
+
+        for aid, _ in auth_events:
+            aev = yield _get_event(aid, event_map, state_res_store)
+            if (aev.type, aev.state_key) == (EventTypes.PowerLevels, ""):
+                event = aev
+                break
+
+    # Didn't find a power level auth event, so we just return 0
+    defer.returnValue(0)
+
+
+@defer.inlineCallbacks
+def _get_event(event_id, event_map, state_res_store):
+    """Helper function to look up event in event_map, falling back to looking
+    it up in the store
+
+    Args:
+        event_id (str)
+        event_map (dict[str,FrozenEvent])
+        state_res_store (StateResolutionStore)
+
+    Returns:
+        Deferred[FrozenEvent]
+    """
+    if event_id not in event_map:
+        events = yield state_res_store.get_events([event_id], allow_rejected=True)
+        event_map.update(events)
+    defer.returnValue(event_map[event_id])
+
+
+def lexicographical_topological_sort(graph, key):
+    """Performs a lexicographic reverse topological sort on the graph.
+
+    This returns a reverse topological sort (i.e. if node A references B then B
+    appears before A in the sort), with ties broken lexicographically based on
+    return value of the `key` function.
+
+    NOTE: `graph` is modified during the sort.
+
+    Args:
+        graph (dict[str, set[str]]): A representation of the graph where each
+            node is a key in the dict and its value are the nodes edges.
+        key (func): A function that takes a node and returns a value that is
+            comparable and used to order nodes
+
+    Yields:
+        str: The next node in the topological sort
+    """
+
+    # Note, this is basically Kahn's algorithm except we look at nodes with no
+    # outgoing edges, c.f.
+    # https://en.wikipedia.org/wiki/Topological_sorting#Kahn's_algorithm
+    outdegree_map = graph
+    reverse_graph = {}
+
+    # Lists of nodes with zero out degree. Is actually a tuple of
+    # `(key(node), node)` so that sorting does the right thing
+    zero_outdegree = []
+
+    for node, edges in iteritems(graph):
+        if len(edges) == 0:
+            zero_outdegree.append((key(node), node))
+
+        reverse_graph.setdefault(node, set())
+        for edge in edges:
+            reverse_graph.setdefault(edge, set()).add(node)
+
+    # heapq is a built in implementation of a sorted queue.
+    heapq.heapify(zero_outdegree)
+
+    while zero_outdegree:
+        _, node = heapq.heappop(zero_outdegree)
+
+        for parent in reverse_graph[node]:
+            out = outdegree_map[parent]
+            out.discard(node)
+            if len(out) == 0:
+                heapq.heappush(zero_outdegree, (key(parent), parent))
+
+        yield node

synapse/storage/events.py

@@ -34,6 +34,7 @@ from synapse.api.errors import SynapseError
 from synapse.events import EventBase  # noqa: F401
 from synapse.events.snapshot import EventContext  # noqa: F401
 from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.state import StateResolutionStore
 from synapse.storage.background_updates import BackgroundUpdateStore
 from synapse.storage.event_federation import EventFederationStore
 from synapse.storage.events_worker import EventsWorkerStore
@@ -731,11 +732,6 @@ class EventsStore(EventFederationStore, EventsWorkerStore, BackgroundUpdateStore
 
         # Ok, we need to defer to the state handler to resolve our state sets.
 
-        def get_events(ev_ids):
-            return self.get_events(
-                ev_ids, get_prev_content=False, check_redacted=False,
-            )
-
         state_groups = {
             sg: state_groups_map[sg] for sg in new_state_groups
         }
@@ -745,7 +741,8 @@ class EventsStore(EventFederationStore, EventsWorkerStore, BackgroundUpdateStore
 
         logger.debug("calling resolve_state_groups from preserve_events")
         res = yield self._state_resolution_handler.resolve_state_groups(
-            room_id, room_version, state_groups, events_map, get_events
+            room_id, room_version, state_groups, events_map,
+            state_res_store=StateResolutionStore(self)
         )
 
         defer.returnValue((res.state, None))
@@ -854,6 +851,27 @@ class EventsStore(EventFederationStore, EventsWorkerStore, BackgroundUpdateStore
         # Insert into event_to_state_groups.
         self._store_event_state_mappings_txn(txn, events_and_contexts)
 
+        # We want to store event_auth mappings for rejected events, as they're
+        # used in state res v2.
+        # This is only necessary if the rejected event appears in an accepted
+        # event's auth chain, but its easier for now just to store them (and
+        # it doesn't take much storage compared to storing the entire event
+        # anyway).
+        self._simple_insert_many_txn(
+            txn,
+            table="event_auth",
+            values=[
+                {
+                    "event_id": event.event_id,
+                    "room_id": event.room_id,
+                    "auth_id": auth_id,
+                }
+                for event, _ in events_and_contexts
+                for auth_id, _ in event.auth_events
+                if event.is_state()
+            ],
+        )
+
         # _store_rejected_events_txn filters out any events which were
         # rejected, and returns the filtered list.
         events_and_contexts = self._store_rejected_events_txn(
@@ -1329,21 +1347,6 @@ class EventsStore(EventFederationStore, EventsWorkerStore, BackgroundUpdateStore
                     txn, event.room_id, event.redacts
                 )
 
-        self._simple_insert_many_txn(
-            txn,
-            table="event_auth",
-            values=[
-                {
-                    "event_id": event.event_id,
-                    "room_id": event.room_id,
-                    "auth_id": auth_id,
-                }
-                for event, _ in events_and_contexts
-                for auth_id, _ in event.auth_events
-                if event.is_state()
-            ],
-        )
-
         # Update the event_forward_extremities, event_backward_extremities and
         # event_edges tables.
         self._handle_mult_prev_events(

synapse/storage/registration.py

@@ -575,7 +575,7 @@ class RegistrationStore(RegistrationWorkerStore,
         def _find_next_generated_user_id(txn):
             txn.execute("SELECT name FROM users")
 
-            regex = re.compile("^@(\d+):")
+            regex = re.compile(r"^@(\d+):")
 
             found = set()
 

synapse/util/logcontext.py

@@ -25,7 +25,7 @@ See doc/log_contexts.rst for details on how this works.
 import logging
 import threading
 
-from twisted.internet import defer
+from twisted.internet import defer, threads
 
 logger = logging.getLogger(__name__)
 
@@ -562,58 +562,76 @@ def _set_context_cb(result, context):
     return result
 
 
-# modules to ignore in `logcontext_tracer`
+def defer_to_thread(reactor, f, *args, **kwargs):
-_to_ignore = [
-    "synapse.util.logcontext",
-    "synapse.http.server",
-    "synapse.storage._base",
-    "synapse.util.async_helpers",
-]
-
-
-def logcontext_tracer(frame, event, arg):
-    """A tracer that logs whenever a logcontext "unexpectedly" changes within
-    a function. Probably inaccurate.
-
-    Use by calling `sys.settrace(logcontext_tracer)` in the main thread.
     """
-    if event == 'call':
+    Calls the function `f` using a thread from the reactor's default threadpool and
-        name = frame.f_globals["__name__"]
+    returns the result as a Deferred.
-        if name.startswith("synapse"):
-            if name == "synapse.util.logcontext":
-                if frame.f_code.co_name in ["__enter__", "__exit__"]:
-                    tracer = frame.f_back.f_trace
-                    if tracer:
-                        tracer.just_changed = True
 
-            tracer = frame.f_trace
+    Creates a new logcontext for `f`, which is created as a child of the current
-            if tracer:
+    logcontext (so its CPU usage metrics will get attributed to the current
-                return tracer
+    logcontext). `f` should preserve the logcontext it is given.
 
-            if not any(name.startswith(ig) for ig in _to_ignore):
+    The result deferred follows the Synapse logcontext rules: you should `yield`
-                return LineTracer()
+    on it.
+
+    Args:
+        reactor (twisted.internet.base.ReactorBase): The reactor in whose main thread
+            the Deferred will be invoked, and whose threadpool we should use for the
+            function.
+
+            Normally this will be hs.get_reactor().
+
+        f (callable): The function to call.
+
+        args: positional arguments to pass to f.
+
+        kwargs: keyword arguments to pass to f.
+
+    Returns:
+        Deferred: A Deferred which fires a callback with the result of `f`, or an
+            errback if `f` throws an exception.
+    """
+    return defer_to_threadpool(reactor, reactor.getThreadPool(), f, *args, **kwargs)
 
 
-class LineTracer(object):
+def defer_to_threadpool(reactor, threadpool, f, *args, **kwargs):
-    __slots__ = ["context", "just_changed"]
+    """
+    A wrapper for twisted.internet.threads.deferToThreadpool, which handles
+    logcontexts correctly.
 
-    def __init__(self):
+    Calls the function `f` using a thread from the given threadpool and returns
-        self.context = LoggingContext.current_context()
+    the result as a Deferred.
-        self.just_changed = False
 
-    def __call__(self, frame, event, arg):
+    Creates a new logcontext for `f`, which is created as a child of the current
-        if event in 'line':
+    logcontext (so its CPU usage metrics will get attributed to the current
-            if self.just_changed:
+    logcontext). `f` should preserve the logcontext it is given.
-                self.context = LoggingContext.current_context()
+
-                self.just_changed = False
+    The result deferred follows the Synapse logcontext rules: you should `yield`
-            else:
+    on it.
-                c = LoggingContext.current_context()
+
-                if c != self.context:
+    Args:
-                    logger.info(
+        reactor (twisted.internet.base.ReactorBase): The reactor in whose main thread
-                        "Context changed! %s -> %s, %s, %s",
+            the Deferred will be invoked. Normally this will be hs.get_reactor().
-                        self.context, c,
+
-                        frame.f_code.co_filename, frame.f_lineno
+        threadpool (twisted.python.threadpool.ThreadPool): The threadpool to use for
+            running `f`. Normally this will be hs.get_reactor().getThreadPool().
+
+        f (callable): The function to call.
+
+        args: positional arguments to pass to f.
+
+        kwargs: keyword arguments to pass to f.
+
+    Returns:
+        Deferred: A Deferred which fires a callback with the result of `f`, or an
+            errback if `f` throws an exception.
+    """
+    logcontext = LoggingContext.current_context()
+
+    def g():
+        with LoggingContext(parent_context=logcontext):
+            return f(*args, **kwargs)
+
+    return make_deferred_yieldable(
+        threads.deferToThreadPool(reactor, threadpool, g)
     )
-                    self.context = c
-
-        return self

tests/api/test_filtering.py

@@ -60,7 +60,7 @@ class FilteringTestCase(unittest.TestCase):
         invalid_filters = [
             {"boom": {}},
             {"account_data": "Hello World"},
-            {"event_fields": ["\\foo"]},
+            {"event_fields": [r"\\foo"]},
             {"room": {"timeline": {"limit": 0}, "state": {"not_bars": ["*"]}}},
             {"event_format": "other"},
             {"room": {"not_rooms": ["#foo:pik-test"]}},
@@ -109,6 +109,16 @@ class FilteringTestCase(unittest.TestCase):
                 "event_format": "client",
                 "event_fields": ["type", "content", "sender"],
             },
+
+            # a single backslash should be permitted (though it is debatable whether
+            # it should be permitted before anything other than `.`, and what that
+            # actually means)
+            #
+            # (note that event_fields is implemented in
+            # synapse.events.utils.serialize_event, and so whether this actually works
+            # is tested elsewhere. We just want to check that it is allowed through the
+            # filter validation)
+            {"event_fields": [r"foo\.bar"]},
         ]
         for filter in valid_filters:
             try:

tests/config/test_generate.py

@@ -67,6 +67,6 @@ class ConfigGenerationTestCase(unittest.TestCase):
         with open(log_config_file) as f:
             config = f.read()
             # find the 'filename' line
-            matches = re.findall("^\s*filename:\s*(.*)$", config, re.M)
+            matches = re.findall(r"^\s*filename:\s*(.*)$", config, re.M)
             self.assertEqual(1, len(matches))
             self.assertEqual(matches[0], expected)

tests/events/test_utils.py

@@ -156,7 +156,7 @@ class SerializeEventTestCase(unittest.TestCase):
                     room_id="!foo:bar",
                     content={"key.with.dots": {}},
                 ),
-                ["content.key\.with\.dots"],
+                [r"content.key\.with\.dots"],
             ),
             {"content": {"key.with.dots": {}}},
         )
@@ -172,7 +172,7 @@ class SerializeEventTestCase(unittest.TestCase):
                         "nested.dot.key": {"leaf.key": 42, "not_me_either": 1},
                     },
                 ),
-                ["content.nested\.dot\.key.leaf\.key"],
+                [r"content.nested\.dot\.key.leaf\.key"],
             ),
             {"content": {"nested.dot.key": {"leaf.key": 42}}},
         )

tests/state/test_v2.py

@@ -0,0 +1,663 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 New Vector Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import itertools
+
+from six.moves import zip
+
+import attr
+
+from synapse.api.constants import EventTypes, JoinRules, Membership
+from synapse.event_auth import auth_types_for_event
+from synapse.events import FrozenEvent
+from synapse.state.v2 import lexicographical_topological_sort, resolve_events_with_store
+from synapse.types import EventID
+
+from tests import unittest
+
+ALICE = "@alice:example.com"
+BOB = "@bob:example.com"
+CHARLIE = "@charlie:example.com"
+EVELYN = "@evelyn:example.com"
+ZARA = "@zara:example.com"
+
+ROOM_ID = "!test:example.com"
+
+MEMBERSHIP_CONTENT_JOIN = {"membership": Membership.JOIN}
+MEMBERSHIP_CONTENT_BAN = {"membership": Membership.BAN}
+
+
+ORIGIN_SERVER_TS = 0
+
+
+class FakeEvent(object):
+    """A fake event we use as a convenience.
+
+    NOTE: Again as a convenience we use "node_ids" rather than event_ids to
+    refer to events. The event_id has node_id as localpart and example.com
+    as domain.
+    """
+    def __init__(self, id, sender, type, state_key, content):
+        self.node_id = id
+        self.event_id = EventID(id, "example.com").to_string()
+        self.sender = sender
+        self.type = type
+        self.state_key = state_key
+        self.content = content
+
+    def to_event(self, auth_events, prev_events):
+        """Given the auth_events and prev_events, convert to a Frozen Event
+
+        Args:
+            auth_events (list[str]): list of event_ids
+            prev_events (list[str]): list of event_ids
+
+        Returns:
+            FrozenEvent
+        """
+        global ORIGIN_SERVER_TS
+
+        ts = ORIGIN_SERVER_TS
+        ORIGIN_SERVER_TS = ORIGIN_SERVER_TS + 1
+
+        event_dict = {
+            "auth_events": [(a, {}) for a in auth_events],
+            "prev_events": [(p, {}) for p in prev_events],
+            "event_id": self.node_id,
+            "sender": self.sender,
+            "type": self.type,
+            "content": self.content,
+            "origin_server_ts": ts,
+            "room_id": ROOM_ID,
+        }
+
+        if self.state_key is not None:
+            event_dict["state_key"] = self.state_key
+
+        return FrozenEvent(event_dict)
+
+
+# All graphs start with this set of events
+INITIAL_EVENTS = [
+    FakeEvent(
+        id="CREATE",
+        sender=ALICE,
+        type=EventTypes.Create,
+        state_key="",
+        content={"creator": ALICE},
+    ),
+    FakeEvent(
+        id="IMA",
+        sender=ALICE,
+        type=EventTypes.Member,
+        state_key=ALICE,
+        content=MEMBERSHIP_CONTENT_JOIN,
+    ),
+    FakeEvent(
+        id="IPOWER",
+        sender=ALICE,
+        type=EventTypes.PowerLevels,
+        state_key="",
+        content={"users": {ALICE: 100}},
+    ),
+    FakeEvent(
+        id="IJR",
+        sender=ALICE,
+        type=EventTypes.JoinRules,
+        state_key="",
+        content={"join_rule": JoinRules.PUBLIC},
+    ),
+    FakeEvent(
+        id="IMB",
+        sender=BOB,
+        type=EventTypes.Member,
+        state_key=BOB,
+        content=MEMBERSHIP_CONTENT_JOIN,
+    ),
+    FakeEvent(
+        id="IMC",
+        sender=CHARLIE,
+        type=EventTypes.Member,
+        state_key=CHARLIE,
+        content=MEMBERSHIP_CONTENT_JOIN,
+    ),
+    FakeEvent(
+        id="IMZ",
+        sender=ZARA,
+        type=EventTypes.Member,
+        state_key=ZARA,
+        content=MEMBERSHIP_CONTENT_JOIN,
+    ),
+    FakeEvent(
+        id="START",
+        sender=ZARA,
+        type=EventTypes.Message,
+        state_key=None,
+        content={},
+    ),
+    FakeEvent(
+        id="END",
+        sender=ZARA,
+        type=EventTypes.Message,
+        state_key=None,
+        content={},
+    ),
+]
+
+INITIAL_EDGES = [
+    "START", "IMZ", "IMC", "IMB", "IJR", "IPOWER", "IMA", "CREATE",
+]
+
+
+class StateTestCase(unittest.TestCase):
+    def test_ban_vs_pl(self):
+        events = [
+            FakeEvent(
+                id="PA",
+                sender=ALICE,
+                type=EventTypes.PowerLevels,
+                state_key="",
+                content={
+                    "users": {
+                        ALICE: 100,
+                        BOB: 50,
+                    }
+                },
+            ),
+            FakeEvent(
+                id="MA",
+                sender=ALICE,
+                type=EventTypes.Member,
+                state_key=ALICE,
+                content={"membership": Membership.JOIN},
+            ),
+            FakeEvent(
+                id="MB",
+                sender=ALICE,
+                type=EventTypes.Member,
+                state_key=BOB,
+                content={"membership": Membership.BAN},
+            ),
+            FakeEvent(
+                id="PB",
+                sender=BOB,
+                type=EventTypes.PowerLevels,
+                state_key='',
+                content={
+                    "users": {
+                        ALICE: 100,
+                        BOB: 50,
+                    },
+                },
+            ),
+        ]
+
+        edges = [
+            ["END", "MB", "MA", "PA", "START"],
+            ["END", "PB", "PA"],
+        ]
+
+        expected_state_ids = ["PA", "MA", "MB"]
+
+        self.do_check(events, edges, expected_state_ids)
+
+    def test_join_rule_evasion(self):
+        events = [
+            FakeEvent(
+                id="JR",
+                sender=ALICE,
+                type=EventTypes.JoinRules,
+                state_key="",
+                content={"join_rules": JoinRules.PRIVATE},
+            ),
+            FakeEvent(
+                id="ME",
+                sender=EVELYN,
+                type=EventTypes.Member,
+                state_key=EVELYN,
+                content={"membership": Membership.JOIN},
+            ),
+        ]
+
+        edges = [
+            ["END", "JR", "START"],
+            ["END", "ME", "START"],
+        ]
+
+        expected_state_ids = ["JR"]
+
+        self.do_check(events, edges, expected_state_ids)
+
+    def test_offtopic_pl(self):
+        events = [
+            FakeEvent(
+                id="PA",
+                sender=ALICE,
+                type=EventTypes.PowerLevels,
+                state_key="",
+                content={
+                    "users": {
+                        ALICE: 100,
+                        BOB: 50,
+                    }
+                },
+            ),
+            FakeEvent(
+                id="PB",
+                sender=BOB,
+                type=EventTypes.PowerLevels,
+                state_key='',
+                content={
+                    "users": {
+                        ALICE: 100,
+                        BOB: 50,
+                        CHARLIE: 50,
+                    },
+                },
+            ),
+            FakeEvent(
+                id="PC",
+                sender=CHARLIE,
+                type=EventTypes.PowerLevels,
+                state_key='',
+                content={
+                    "users": {
+                        ALICE: 100,
+                        BOB: 50,
+                        CHARLIE: 0,
+                    },
+                },
+            ),
+        ]
+
+        edges = [
+            ["END", "PC", "PB", "PA", "START"],
+            ["END", "PA"],
+        ]
+
+        expected_state_ids = ["PC"]
+
+        self.do_check(events, edges, expected_state_ids)
+
+    def test_topic_basic(self):
+        events = [
+            FakeEvent(
+                id="T1",
+                sender=ALICE,
+                type=EventTypes.Topic,
+                state_key="",
+                content={},
+            ),
+            FakeEvent(
+                id="PA1",
+                sender=ALICE,
+                type=EventTypes.PowerLevels,
+                state_key='',
+                content={
+                    "users": {
+                        ALICE: 100,
+                        BOB: 50,
+                    },
+                },
+            ),
+            FakeEvent(
+                id="T2",
+                sender=ALICE,
+                type=EventTypes.Topic,
+                state_key="",
+                content={},
+            ),
+            FakeEvent(
+                id="PA2",
+                sender=ALICE,
+                type=EventTypes.PowerLevels,
+                state_key='',
+                content={
+                    "users": {
+                        ALICE: 100,
+                        BOB: 0,
+                    },
+                },
+            ),
+            FakeEvent(
+                id="PB",
+                sender=BOB,
+                type=EventTypes.PowerLevels,
+                state_key='',
+                content={
+                    "users": {
+                        ALICE: 100,
+                        BOB: 50,
+                    },
+                },
+            ),
+            FakeEvent(
+                id="T3",
+                sender=BOB,
+                type=EventTypes.Topic,
+                state_key="",
+                content={},
+            ),
+        ]
+
+        edges = [
+            ["END", "PA2", "T2", "PA1", "T1", "START"],
+            ["END", "T3", "PB", "PA1"],
+        ]
+
+        expected_state_ids = ["PA2", "T2"]
+
+        self.do_check(events, edges, expected_state_ids)
+
+    def test_topic_reset(self):
+        events = [
+            FakeEvent(
+                id="T1",
+                sender=ALICE,
+                type=EventTypes.Topic,
+                state_key="",
+                content={},
+            ),
+            FakeEvent(
+                id="PA",
+                sender=ALICE,
+                type=EventTypes.PowerLevels,
+                state_key='',
+                content={
+                    "users": {
+                        ALICE: 100,
+                        BOB: 50,
+                    },
+                },
+            ),
+            FakeEvent(
+                id="T2",
+                sender=BOB,
+                type=EventTypes.Topic,
+                state_key="",
+                content={},
+            ),
+            FakeEvent(
+                id="MB",
+                sender=ALICE,
+                type=EventTypes.Member,
+                state_key=BOB,
+                content={"membership": Membership.BAN},
+            ),
+        ]
+
+        edges = [
+            ["END", "MB", "T2", "PA", "T1", "START"],
+            ["END", "T1"],
+        ]
+
+        expected_state_ids = ["T1", "MB", "PA"]
+
+        self.do_check(events, edges, expected_state_ids)
+
+    def test_topic(self):
+        events = [
+            FakeEvent(
+                id="T1",
+                sender=ALICE,
+                type=EventTypes.Topic,
+                state_key="",
+                content={},
+            ),
+            FakeEvent(
+                id="PA1",
+                sender=ALICE,
+                type=EventTypes.PowerLevels,
+                state_key='',
+                content={
+                    "users": {
+                        ALICE: 100,
+                        BOB: 50,
+                    },
+                },
+            ),
+            FakeEvent(
+                id="T2",
+                sender=ALICE,
+                type=EventTypes.Topic,
+                state_key="",
+                content={},
+            ),
+            FakeEvent(
+                id="PA2",
+                sender=ALICE,
+                type=EventTypes.PowerLevels,
+                state_key='',
+                content={
+                    "users": {
+                        ALICE: 100,
+                        BOB: 0,
+                    },
+                },
+            ),
+            FakeEvent(
+                id="PB",
+                sender=BOB,
+                type=EventTypes.PowerLevels,
+                state_key='',
+                content={
+                    "users": {
+                        ALICE: 100,
+                        BOB: 50,
+                    },
+                },
+            ),
+            FakeEvent(
+                id="T3",
+                sender=BOB,
+                type=EventTypes.Topic,
+                state_key="",
+                content={},
+            ),
+            FakeEvent(
+                id="MZ1",
+                sender=ZARA,
+                type=EventTypes.Message,
+                state_key=None,
+                content={},
+            ),
+            FakeEvent(
+                id="T4",
+                sender=ALICE,
+                type=EventTypes.Topic,
+                state_key="",
+                content={},
+            ),
+        ]
+
+        edges = [
+            ["END", "T4", "MZ1", "PA2", "T2", "PA1", "T1", "START"],
+            ["END", "MZ1", "T3", "PB", "PA1"],
+        ]
+
+        expected_state_ids = ["T4", "PA2"]
+
+        self.do_check(events, edges, expected_state_ids)
+
+    def do_check(self, events, edges, expected_state_ids):
+        """Take a list of events and edges and calculate the state of the
+        graph at END, and asserts it matches `expected_state_ids`
+
+        Args:
+            events (list[FakeEvent])
+            edges (list[list[str]]): A list of chains of event edges, e.g.
+                `[[A, B, C]]` are edges A->B and B->C.
+            expected_state_ids (list[str]): The expected state at END, (excluding
+                the keys that haven't changed since START).
+        """
+        # We want to sort the events into topological order for processing.
+        graph = {}
+
+        # node_id -> FakeEvent
+        fake_event_map = {}
+
+        for ev in itertools.chain(INITIAL_EVENTS, events):
+            graph[ev.node_id] = set()
+            fake_event_map[ev.node_id] = ev
+
+        for a, b in pairwise(INITIAL_EDGES):
+            graph[a].add(b)
+
+        for edge_list in edges:
+            for a, b in pairwise(edge_list):
+                graph[a].add(b)
+
+        # event_id -> FrozenEvent
+        event_map = {}
+        # node_id -> state
+        state_at_event = {}
+
+        # We copy the map as the sort consumes the graph
+        graph_copy = {k: set(v) for k, v in graph.items()}
+
+        for node_id in lexicographical_topological_sort(graph_copy, key=lambda e: e):
+            fake_event = fake_event_map[node_id]
+            event_id = fake_event.event_id
+
+            prev_events = list(graph[node_id])
+
+            if len(prev_events) == 0:
+                state_before = {}
+            elif len(prev_events) == 1:
+                state_before = dict(state_at_event[prev_events[0]])
+            else:
+                state_d = resolve_events_with_store(
+                    [state_at_event[n] for n in prev_events],
+                    event_map=event_map,
+                    state_res_store=TestStateResolutionStore(event_map),
+                )
+
+                self.assertTrue(state_d.called)
+                state_before = state_d.result
+
+            state_after = dict(state_before)
+            if fake_event.state_key is not None:
+                state_after[(fake_event.type, fake_event.state_key)] = event_id
+
+            auth_types = set(auth_types_for_event(fake_event))
+
+            auth_events = []
+            for key in auth_types:
+                if key in state_before:
+                    auth_events.append(state_before[key])
+
+            event = fake_event.to_event(auth_events, prev_events)
+
+            state_at_event[node_id] = state_after
+            event_map[event_id] = event
+
+        expected_state = {}
+        for node_id in expected_state_ids:
+            # expected_state_ids are node IDs rather than event IDs,
+            # so we have to convert
+            event_id = EventID(node_id, "example.com").to_string()
+            event = event_map[event_id]
+
+            key = (event.type, event.state_key)
+
+            expected_state[key] = event_id
+
+        start_state = state_at_event["START"]
+        end_state = {
+            key: value
+            for key, value in state_at_event["END"].items()
+            if key in expected_state or start_state.get(key) != value
+        }
+
+        self.assertEqual(expected_state, end_state)
+
+
+class LexicographicalTestCase(unittest.TestCase):
+    def test_simple(self):
+        graph = {
+            "l": {"o"},
+            "m": {"n", "o"},
+            "n": {"o"},
+            "o": set(),
+            "p": {"o"},
+        }
+
+        res = list(lexicographical_topological_sort(graph, key=lambda x: x))
+
+        self.assertEqual(["o", "l", "n", "m", "p"], res)
+
+
+def pairwise(iterable):
+    "s -> (s0,s1), (s1,s2), (s2, s3), ..."
+    a, b = itertools.tee(iterable)
+    next(b, None)
+    return zip(a, b)
+
+
+@attr.s
+class TestStateResolutionStore(object):
+    event_map = attr.ib()
+
+    def get_events(self, event_ids, allow_rejected=False):
+        """Get events from the database
+
+        Args:
+            event_ids (list): The event_ids of the events to fetch
+            allow_rejected (bool): If True return rejected events.
+
+        Returns:
+            Deferred[dict[str, FrozenEvent]]: Dict from event_id to event.
+        """
+
+        return {
+            eid: self.event_map[eid]
+            for eid in event_ids
+            if eid in self.event_map
+        }
+
+    def get_auth_chain(self, event_ids):
+        """Gets the full auth chain for a set of events (including rejected
+        events).
+
+        Includes the given event IDs in the result.
+
+        Note that:
+            1. All events must be state events.
+            2. For v1 rooms this may not have the full auth chain in the
+               presence of rejected events
+
+        Args:
+            event_ids (list): The event IDs of the events to fetch the auth
+                chain for. Must be state events.
+
+        Returns:
+            Deferred[list[str]]: List of event IDs of the auth chain.
+        """
+
+        # Simple DFS for auth chain
+        result = set()
+        stack = list(event_ids)
+        while stack:
+            event_id = stack.pop()
+            if event_id in result:
+                continue
+
+            result.add(event_id)
+
+            event = self.event_map[event_id]
+            for aid, _ in event.auth_events:
+                stack.append(aid)
+
+        return list(result)