Convert state resolution to async/await (#7942)

3 files changed, 97 insertions, 120 deletions

diff --git a/synapse/state/__init__.py b/synapse/state/__init__.py
index 495d9f04c8..25ccef5aa5 100644
--- a/synapse/state/__init__.py
+++ b/synapse/state/__init__.py
@@ -16,14 +16,12 @@
 
 import logging
 from collections import namedtuple
-from typing import Dict, Iterable, List, Optional, Set
+from typing import Awaitable, Dict, Iterable, List, Optional, Set
 
 import attr
 from frozendict import frozendict
 from prometheus_client import Histogram
 
-from twisted.internet import defer
-
 from synapse.api.constants import EventTypes
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, StateResolutionVersions
 from synapse.events import EventBase
@@ -31,6 +29,7 @@ from synapse.events.snapshot import EventContext
 from synapse.logging.utils import log_function
 from synapse.state import v1, v2
 from synapse.storage.data_stores.main.events_worker import EventRedactBehaviour
+from synapse.storage.roommember import ProfileInfo
 from synapse.types import StateMap
 from synapse.util import Clock
 from synapse.util.async_helpers import Linearizer
@@ -108,8 +107,7 @@ class StateHandler(object):
         self.hs = hs
         self._state_resolution_handler = hs.get_state_resolution_handler()
 
-    @defer.inlineCallbacks
-    def get_current_state(
+    async def get_current_state(
         self, room_id, event_type=None, state_key="", latest_event_ids=None
     ):
         """ Retrieves the current state for the room. This is done by
@@ -126,20 +124,20 @@ class StateHandler(object):
             map from (type, state_key) to event
         """
         if not latest_event_ids:
-            latest_event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
+            latest_event_ids = await self.store.get_latest_event_ids_in_room(room_id)
 
         logger.debug("calling resolve_state_groups from get_current_state")
-        ret = yield self.resolve_state_groups_for_events(room_id, latest_event_ids)
+        ret = await self.resolve_state_groups_for_events(room_id, latest_event_ids)
         state = ret.state
 
         if event_type:
             event_id = state.get((event_type, state_key))
             event = None
             if event_id:
-                event = yield self.store.get_event(event_id, allow_none=True)
+                event = await self.store.get_event(event_id, allow_none=True)
             return event
 
-        state_map = yield self.store.get_events(
+        state_map = await self.store.get_events(
             list(state.values()), get_prev_content=False
         )
         state = {
@@ -148,8 +146,7 @@ class StateHandler(object):
 
         return state
 
-    @defer.inlineCallbacks
-    def get_current_state_ids(self, room_id, latest_event_ids=None):
+    async def get_current_state_ids(self, room_id, latest_event_ids=None):
         """Get the current state, or the state at a set of events, for a room
 
         Args:
@@ -164,41 +161,38 @@ class StateHandler(object):
                 (event_type, state_key) -> event_id
         """
         if not latest_event_ids:
-            latest_event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
+            latest_event_ids = await self.store.get_latest_event_ids_in_room(room_id)
 
         logger.debug("calling resolve_state_groups from get_current_state_ids")
-        ret = yield self.resolve_state_groups_for_events(room_id, latest_event_ids)
+        ret = await self.resolve_state_groups_for_events(room_id, latest_event_ids)
         state = ret.state
 
         return state
 
-    @defer.inlineCallbacks
-    def get_current_users_in_room(self, room_id, latest_event_ids=None):
+    async def get_current_users_in_room(
+        self, room_id: str, latest_event_ids: Optional[List[str]] = None
+    ) -> Dict[str, ProfileInfo]:
         """
         Get the users who are currently in a room.
 
         Args:
-            room_id (str): The ID of the room.
-            latest_event_ids (List[str]|None): Precomputed list of latest
-                event IDs. Will be computed if None.
+            room_id: The ID of the room.
+            latest_event_ids: Precomputed list of latest event IDs. Will be computed if None.
         Returns:
-            Deferred[Dict[str,ProfileInfo]]: Dictionary of user IDs to their
-                profileinfo.
+            Dictionary of user IDs to their profileinfo.
         """
         if not latest_event_ids:
-            latest_event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
+            latest_event_ids = await self.store.get_latest_event_ids_in_room(room_id)
         logger.debug("calling resolve_state_groups from get_current_users_in_room")
-        entry = yield self.resolve_state_groups_for_events(room_id, latest_event_ids)
-        joined_users = yield self.store.get_joined_users_from_state(room_id, entry)
+        entry = await self.resolve_state_groups_for_events(room_id, latest_event_ids)
+        joined_users = await self.store.get_joined_users_from_state(room_id, entry)
         return joined_users
 
-    @defer.inlineCallbacks
-    def get_current_hosts_in_room(self, room_id):
-        event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
-        return (yield self.get_hosts_in_room_at_events(room_id, event_ids))
+    async def get_current_hosts_in_room(self, room_id):
+        event_ids = await self.store.get_latest_event_ids_in_room(room_id)
+        return await self.get_hosts_in_room_at_events(room_id, event_ids)
 
-    @defer.inlineCallbacks
-    def get_hosts_in_room_at_events(self, room_id, event_ids):
+    async def get_hosts_in_room_at_events(self, room_id, event_ids):
         """Get the hosts that were in a room at the given event ids
 
         Args:
@@ -208,12 +202,11 @@ class StateHandler(object):
         Returns:
             Deferred[list[str]]: the hosts in the room at the given events
         """
-        entry = yield self.resolve_state_groups_for_events(room_id, event_ids)
-        joined_hosts = yield self.store.get_joined_hosts(room_id, entry)
+        entry = await self.resolve_state_groups_for_events(room_id, event_ids)
+        joined_hosts = await self.store.get_joined_hosts(room_id, entry)
         return joined_hosts
 
-    @defer.inlineCallbacks
-    def compute_event_context(
+    async def compute_event_context(
         self, event: EventBase, old_state: Optional[Iterable[EventBase]] = None
     ):
         """Build an EventContext structure for the event.
@@ -278,7 +271,7 @@ class StateHandler(object):
             # otherwise, we'll need to resolve the state across the prev_events.
             logger.debug("calling resolve_state_groups from compute_event_context")
 
-            entry = yield self.resolve_state_groups_for_events(
+            entry = await self.resolve_state_groups_for_events(
                 event.room_id, event.prev_event_ids()
             )
 
@@ -295,7 +288,7 @@ class StateHandler(object):
         #
 
         if not state_group_before_event:
-            state_group_before_event = yield self.state_store.store_state_group(
+            state_group_before_event = await self.state_store.store_state_group(
                 event.event_id,
                 event.room_id,
                 prev_group=state_group_before_event_prev_group,
@@ -335,7 +328,7 @@ class StateHandler(object):
         state_ids_after_event[key] = event.event_id
         delta_ids = {key: event.event_id}
 
-        state_group_after_event = yield self.state_store.store_state_group(
+        state_group_after_event = await self.state_store.store_state_group(
             event.event_id,
             event.room_id,
             prev_group=state_group_before_event,
@@ -353,8 +346,7 @@ class StateHandler(object):
         )
 
     @measure_func()
-    @defer.inlineCallbacks
-    def resolve_state_groups_for_events(self, room_id, event_ids):
+    async def resolve_state_groups_for_events(self, room_id, event_ids):
         """ Given a list of event_ids this method fetches the state at each
         event, resolves conflicts between them and returns them.
 
@@ -373,7 +365,7 @@ class StateHandler(object):
         # map from state group id to the state in that state group (where
         # 'state' is a map from state key to event id)
         # dict[int, dict[(str, str), str]]
-        state_groups_ids = yield self.state_store.get_state_groups_ids(
+        state_groups_ids = await self.state_store.get_state_groups_ids(
             room_id, event_ids
         )
 
@@ -382,7 +374,7 @@ class StateHandler(object):
         elif len(state_groups_ids) == 1:
             name, state_list = list(state_groups_ids.items()).pop()
 
-            prev_group, delta_ids = yield self.state_store.get_state_group_delta(name)
+            prev_group, delta_ids = await self.state_store.get_state_group_delta(name)
 
             return _StateCacheEntry(
                 state=state_list,
@@ -391,9 +383,9 @@ class StateHandler(object):
                 delta_ids=delta_ids,
             )
 
-        room_version = yield self.store.get_room_version_id(room_id)
+        room_version = await self.store.get_room_version_id(room_id)
 
-        result = yield self._state_resolution_handler.resolve_state_groups(
+        result = await self._state_resolution_handler.resolve_state_groups(
             room_id,
             room_version,
             state_groups_ids,
@@ -402,8 +394,7 @@ class StateHandler(object):
         )
         return result
 
-    @defer.inlineCallbacks
-    def resolve_events(self, room_version, state_sets, event):
+    async def resolve_events(self, room_version, state_sets, event):
         logger.info(
             "Resolving state for %s with %d groups", event.room_id, len(state_sets)
         )
@@ -414,7 +405,7 @@ class StateHandler(object):
         state_map = {ev.event_id: ev for st in state_sets for ev in st}
 
         with Measure(self.clock, "state._resolve_events"):
-            new_state = yield resolve_events_with_store(
+            new_state = await resolve_events_with_store(
                 self.clock,
                 event.room_id,
                 room_version,
@@ -451,9 +442,8 @@ class StateResolutionHandler(object):
             reset_expiry_on_get=True,
         )
 
-    @defer.inlineCallbacks
     @log_function
-    def resolve_state_groups(
+    async def resolve_state_groups(
         self, room_id, room_version, state_groups_ids, event_map, state_res_store
     ):
         """Resolves conflicts between a set of state groups
@@ -479,13 +469,13 @@ class StateResolutionHandler(object):
             state_res_store (StateResolutionStore)
 
         Returns:
-            Deferred[_StateCacheEntry]: resolved state
+            _StateCacheEntry: resolved state
         """
         logger.debug("resolve_state_groups state_groups %s", state_groups_ids.keys())
 
         group_names = frozenset(state_groups_ids.keys())
 
-        with (yield self.resolve_linearizer.queue(group_names)):
+        with (await self.resolve_linearizer.queue(group_names)):
             if self._state_cache is not None:
                 cache = self._state_cache.get(group_names, None)
                 if cache:
@@ -517,7 +507,7 @@ 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_store(
+                    new_state = await resolve_events_with_store(
                         self.clock,
                         room_id,
                         room_version,
@@ -598,7 +588,7 @@ def resolve_events_with_store(
     state_sets: List[StateMap[str]],
     event_map: Optional[Dict[str, EventBase]],
     state_res_store: "StateResolutionStore",
-):
+) -> Awaitable[StateMap[str]]:
     """
     Args:
         room_id: the room we are working in
@@ -619,8 +609,7 @@ def resolve_events_with_store(
         state_res_store: a place to fetch events from
 
     Returns:
-        Deferred[dict[(str, str), str]]:
-            a map from (type, state_key) to event_id.
+        a map from (type, state_key) to event_id.
     """
     v = KNOWN_ROOM_VERSIONS[room_version]
     if v.state_res == StateResolutionVersions.V1:
diff --git a/synapse/state/v1.py b/synapse/state/v1.py
index 7b531a8337..ab5e24841d 100644
--- a/synapse/state/v1.py
+++ b/synapse/state/v1.py
@@ -15,9 +15,7 @@
 
 import hashlib
 import logging
-from typing import Callable, Dict, List, Optional
-
-from twisted.internet import defer
+from typing import Awaitable, Callable, Dict, List, Optional
 
 from synapse import event_auth
 from synapse.api.constants import EventTypes
@@ -32,12 +30,11 @@ logger = logging.getLogger(__name__)
 POWER_KEY = (EventTypes.PowerLevels, "")
 
 
-@defer.inlineCallbacks
-def resolve_events_with_store(
+async def resolve_events_with_store(
     room_id: str,
     state_sets: List[StateMap[str]],
     event_map: Optional[Dict[str, EventBase]],
-    state_map_factory: Callable,
+    state_map_factory: Callable[[List[str]], Awaitable],
 ):
     """
     Args:
@@ -56,7 +53,7 @@ def resolve_events_with_store(
 
         state_map_factory: will be called
             with a list of event_ids that are needed, and should return with
-            a Deferred of dict of event_id to event.
+            an Awaitable that resolves to a dict of event_id to event.
 
     Returns:
         Deferred[dict[(str, str), str]]:
@@ -80,7 +77,7 @@ def resolve_events_with_store(
 
     # dict[str, FrozenEvent]: a map from state event id to event. Only includes
     # the state events which are in conflict (and those in event_map)
-    state_map = yield state_map_factory(needed_events)
+    state_map = await state_map_factory(needed_events)
     if event_map is not None:
         state_map.update(event_map)
 
@@ -110,7 +107,7 @@ def resolve_events_with_store(
         "Asking for %d/%d auth events", len(new_needed_events), new_needed_event_count
     )
 
-    state_map_new = yield state_map_factory(new_needed_events)
+    state_map_new = await state_map_factory(new_needed_events)
     for event in state_map_new.values():
         if event.room_id != room_id:
             raise Exception(
diff --git a/synapse/state/v2.py b/synapse/state/v2.py
index bf6caa0946..6634955cdc 100644
--- a/synapse/state/v2.py
+++ b/synapse/state/v2.py
@@ -18,8 +18,6 @@ import itertools
 import logging
 from typing import Dict, List, Optional
 
-from twisted.internet import defer
-
 import synapse.state
 from synapse import event_auth
 from synapse.api.constants import EventTypes
@@ -32,14 +30,13 @@ from synapse.util import Clock
 logger = logging.getLogger(__name__)
 
 
-# We want to yield to the reactor occasionally during state res when dealing
+# We want to await to the reactor occasionally during state res when dealing
 # with large data sets, so that we don't exhaust the reactor. This is done by
-# yielding to reactor during loops every N iterations.
-_YIELD_AFTER_ITERATIONS = 100
+# awaiting to reactor during loops every N iterations.
+_AWAIT_AFTER_ITERATIONS = 100
 
 
-@defer.inlineCallbacks
-def resolve_events_with_store(
+async def resolve_events_with_store(
     clock: Clock,
     room_id: str,
     room_version: str,
@@ -87,7 +84,7 @@ def resolve_events_with_store(
 
     # 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)
+    auth_diff = await _get_auth_chain_difference(state_sets, event_map, state_res_store)
 
     full_conflicted_set = set(
         itertools.chain(
@@ -95,7 +92,7 @@ def resolve_events_with_store(
         )
     )
 
-    events = yield state_res_store.get_events(
+    events = await state_res_store.get_events(
         [eid for eid in full_conflicted_set if eid not in event_map],
         allow_rejected=True,
     )
@@ -118,14 +115,14 @@ def resolve_events_with_store(
         eid for eid in full_conflicted_set if _is_power_event(event_map[eid])
     )
 
-    sorted_power_events = yield _reverse_topological_power_sort(
+    sorted_power_events = await _reverse_topological_power_sort(
         clock, room_id, 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(
+    resolved_state = await _iterative_auth_checks(
         clock,
         room_id,
         room_version,
@@ -148,13 +145,13 @@ def resolve_events_with_store(
     logger.debug("sorting %d remaining events", len(leftover_events))
 
     pl = resolved_state.get((EventTypes.PowerLevels, ""), None)
-    leftover_events = yield _mainline_sort(
+    leftover_events = await _mainline_sort(
         clock, room_id, leftover_events, pl, event_map, state_res_store
     )
 
     logger.debug("resolving remaining events")
 
-    resolved_state = yield _iterative_auth_checks(
+    resolved_state = await _iterative_auth_checks(
         clock,
         room_id,
         room_version,
@@ -174,8 +171,7 @@ def resolve_events_with_store(
     return resolved_state
 
 
-@defer.inlineCallbacks
-def _get_power_level_for_sender(room_id, event_id, event_map, state_res_store):
+async def _get_power_level_for_sender(room_id, event_id, event_map, state_res_store):
     """Return the power level of the sender of the given event according to
     their auth events.
 
@@ -188,11 +184,11 @@ def _get_power_level_for_sender(room_id, event_id, event_map, state_res_store):
     Returns:
         Deferred[int]
     """
-    event = yield _get_event(room_id, event_id, event_map, state_res_store)
+    event = await _get_event(room_id, event_id, event_map, state_res_store)
 
     pl = None
     for aid in event.auth_event_ids():
-        aev = yield _get_event(
+        aev = await _get_event(
             room_id, aid, event_map, state_res_store, allow_none=True
         )
         if aev and (aev.type, aev.state_key) == (EventTypes.PowerLevels, ""):
@@ -202,7 +198,7 @@ def _get_power_level_for_sender(room_id, event_id, event_map, state_res_store):
     if pl is None:
         # Couldn't find power level. Check if they're the creator of the room
         for aid in event.auth_event_ids():
-            aev = yield _get_event(
+            aev = await _get_event(
                 room_id, aid, event_map, state_res_store, allow_none=True
             )
             if aev and (aev.type, aev.state_key) == (EventTypes.Create, ""):
@@ -221,8 +217,7 @@ def _get_power_level_for_sender(room_id, event_id, event_map, state_res_store):
         return int(level)
 
 
-@defer.inlineCallbacks
-def _get_auth_chain_difference(state_sets, event_map, state_res_store):
+async 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.
 
@@ -235,7 +230,7 @@ def _get_auth_chain_difference(state_sets, event_map, state_res_store):
         Deferred[set[str]]: Set of event IDs
     """
 
-    difference = yield state_res_store.get_auth_chain_difference(
+    difference = await state_res_store.get_auth_chain_difference(
         [set(state_set.values()) for state_set in state_sets]
     )
 
@@ -292,8 +287,7 @@ def _is_power_event(event):
     return False
 
 
-@defer.inlineCallbacks
-def _add_event_and_auth_chain_to_graph(
+async def _add_event_and_auth_chain_to_graph(
     graph, room_id, event_id, event_map, state_res_store, auth_diff
 ):
     """Helper function for _reverse_topological_power_sort that add the event
@@ -314,7 +308,7 @@ def _add_event_and_auth_chain_to_graph(
         eid = state.pop()
         graph.setdefault(eid, set())
 
-        event = yield _get_event(room_id, eid, event_map, state_res_store)
+        event = await _get_event(room_id, eid, event_map, state_res_store)
         for aid in event.auth_event_ids():
             if aid in auth_diff:
                 if aid not in graph:
@@ -323,8 +317,7 @@ def _add_event_and_auth_chain_to_graph(
                 graph.setdefault(eid, set()).add(aid)
 
 
-@defer.inlineCallbacks
-def _reverse_topological_power_sort(
+async def _reverse_topological_power_sort(
     clock, room_id, event_ids, event_map, state_res_store, auth_diff
 ):
     """Returns a list of the event_ids sorted by reverse topological ordering,
@@ -344,26 +337,26 @@ def _reverse_topological_power_sort(
 
     graph = {}
     for idx, event_id in enumerate(event_ids, start=1):
-        yield _add_event_and_auth_chain_to_graph(
+        await _add_event_and_auth_chain_to_graph(
             graph, room_id, event_id, event_map, state_res_store, auth_diff
         )
 
-        # We yield occasionally when we're working with large data sets to
+        # We await occasionally when we're working with large data sets to
         # ensure that we don't block the reactor loop for too long.
-        if idx % _YIELD_AFTER_ITERATIONS == 0:
-            yield clock.sleep(0)
+        if idx % _AWAIT_AFTER_ITERATIONS == 0:
+            await clock.sleep(0)
 
     event_to_pl = {}
     for idx, event_id in enumerate(graph, start=1):
-        pl = yield _get_power_level_for_sender(
+        pl = await _get_power_level_for_sender(
             room_id, event_id, event_map, state_res_store
         )
         event_to_pl[event_id] = pl
 
-        # We yield occasionally when we're working with large data sets to
+        # We await occasionally when we're working with large data sets to
         # ensure that we don't block the reactor loop for too long.
-        if idx % _YIELD_AFTER_ITERATIONS == 0:
-            yield clock.sleep(0)
+        if idx % _AWAIT_AFTER_ITERATIONS == 0:
+            await clock.sleep(0)
 
     def _get_power_order(event_id):
         ev = event_map[event_id]
@@ -378,8 +371,7 @@ def _reverse_topological_power_sort(
     return sorted_events
 
 
-@defer.inlineCallbacks
-def _iterative_auth_checks(
+async def _iterative_auth_checks(
     clock, room_id, room_version, event_ids, base_state, event_map, state_res_store
 ):
     """Sequentially apply auth checks to each event in given list, updating the
@@ -405,7 +397,7 @@ def _iterative_auth_checks(
 
         auth_events = {}
         for aid in event.auth_event_ids():
-            ev = yield _get_event(
+            ev = await _get_event(
                 room_id, aid, event_map, state_res_store, allow_none=True
             )
 
@@ -420,7 +412,7 @@ def _iterative_auth_checks(
         for key in event_auth.auth_types_for_event(event):
             if key in resolved_state:
                 ev_id = resolved_state[key]
-                ev = yield _get_event(room_id, ev_id, event_map, state_res_store)
+                ev = await _get_event(room_id, ev_id, event_map, state_res_store)
 
                 if ev.rejected_reason is None:
                     auth_events[key] = event_map[ev_id]
@@ -438,16 +430,15 @@ def _iterative_auth_checks(
         except AuthError:
             pass
 
-        # We yield occasionally when we're working with large data sets to
+        # We await occasionally when we're working with large data sets to
         # ensure that we don't block the reactor loop for too long.
-        if idx % _YIELD_AFTER_ITERATIONS == 0:
-            yield clock.sleep(0)
+        if idx % _AWAIT_AFTER_ITERATIONS == 0:
+            await clock.sleep(0)
 
     return resolved_state
 
 
-@defer.inlineCallbacks
-def _mainline_sort(
+async def _mainline_sort(
     clock, room_id, event_ids, resolved_power_event_id, event_map, state_res_store
 ):
     """Returns a sorted list of event_ids sorted by mainline ordering based on
@@ -474,21 +465,21 @@ def _mainline_sort(
     idx = 0
     while pl:
         mainline.append(pl)
-        pl_ev = yield _get_event(room_id, pl, event_map, state_res_store)
+        pl_ev = await _get_event(room_id, pl, event_map, state_res_store)
         auth_events = pl_ev.auth_event_ids()
         pl = None
         for aid in auth_events:
-            ev = yield _get_event(
+            ev = await _get_event(
                 room_id, aid, event_map, state_res_store, allow_none=True
             )
             if ev and (ev.type, ev.state_key) == (EventTypes.PowerLevels, ""):
                 pl = aid
                 break
 
-        # We yield occasionally when we're working with large data sets to
+        # We await occasionally when we're working with large data sets to
         # ensure that we don't block the reactor loop for too long.
-        if idx != 0 and idx % _YIELD_AFTER_ITERATIONS == 0:
-            yield clock.sleep(0)
+        if idx != 0 and idx % _AWAIT_AFTER_ITERATIONS == 0:
+            await clock.sleep(0)
 
         idx += 1
 
@@ -498,23 +489,24 @@ def _mainline_sort(
 
     order_map = {}
     for idx, ev_id in enumerate(event_ids, start=1):
-        depth = yield _get_mainline_depth_for_event(
+        depth = await _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)
 
-        # We yield occasionally when we're working with large data sets to
+        # We await occasionally when we're working with large data sets to
         # ensure that we don't block the reactor loop for too long.
-        if idx % _YIELD_AFTER_ITERATIONS == 0:
-            yield clock.sleep(0)
+        if idx % _AWAIT_AFTER_ITERATIONS == 0:
+            await clock.sleep(0)
 
     event_ids.sort(key=lambda ev_id: order_map[ev_id])
 
     return event_ids
 
 
-@defer.inlineCallbacks
-def _get_mainline_depth_for_event(event, mainline_map, event_map, state_res_store):
+async 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:
@@ -541,7 +533,7 @@ def _get_mainline_depth_for_event(event, mainline_map, event_map, state_res_stor
         event = None
 
         for aid in auth_events:
-            aev = yield _get_event(
+            aev = await _get_event(
                 room_id, aid, event_map, state_res_store, allow_none=True
             )
             if aev and (aev.type, aev.state_key) == (EventTypes.PowerLevels, ""):
@@ -552,8 +544,7 @@ def _get_mainline_depth_for_event(event, mainline_map, event_map, state_res_stor
     return 0
 
 
-@defer.inlineCallbacks
-def _get_event(room_id, event_id, event_map, state_res_store, allow_none=False):
+async def _get_event(room_id, event_id, event_map, state_res_store, allow_none=False):
     """Helper function to look up event in event_map, falling back to looking
     it up in the store
 
@@ -569,7 +560,7 @@ def _get_event(room_id, event_id, event_map, state_res_store, allow_none=False):
         Deferred[Optional[FrozenEvent]]
     """
     if event_id not in event_map:
-        events = yield state_res_store.get_events([event_id], allow_rejected=True)
+        events = await state_res_store.get_events([event_id], allow_rejected=True)
         event_map.update(events)
     event = event_map.get(event_id)