Factor out a separate EventContext.for_outlier (#10883)

Constructing an EventContext for an outlier is actually really simple, and
there's no sense in going via an `async` method in the `StateHandler`.

This also means that we can resolve a bunch of FIXMEs.
This commit is contained in:
Richard van der Hoff 2021-09-22 17:58:57 +01:00 committed by GitHub
parent f78b68a96b
commit 26f2bfedbf
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5 changed files with 21 additions and 44 deletions

1
changelog.d/10883.misc Normal file
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@ -0,0 +1 @@
Clean up some of the federation event authentication code for clarity.

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@ -80,9 +80,7 @@ class EventContext:
(type, state_key) -> event_id
FIXME: what is this for an outlier? it seems ill-defined. It seems like
it could be either {}, or the state we were given by the remote
server, depending on $THINGS
For an outlier, this is {}
Note that this is a private attribute: it should be accessed via
``get_current_state_ids``. _AsyncEventContext impl calculates this
@ -96,7 +94,7 @@ class EventContext:
(type, state_key) -> event_id
FIXME: again, what is this for an outlier?
For an outlier, this is {}
As with _current_state_ids, this is a private attribute. It should be
accessed via get_prev_state_ids.
@ -130,6 +128,14 @@ class EventContext:
delta_ids=delta_ids,
)
@staticmethod
def for_outlier():
"""Return an EventContext instance suitable for persisting an outlier event"""
return EventContext(
current_state_ids={},
prev_state_ids={},
)
async def serialize(self, event: EventBase, store: "DataStore") -> dict:
"""Converts self to a type that can be serialized as JSON, and then
deserialized by `deserialize`

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@ -624,7 +624,7 @@ class FederationHandler(BaseHandler):
# in the invitee's sync stream. It is stripped out for all other local users.
event.unsigned["knock_room_state"] = stripped_room_state["knock_state_events"]
context = await self.state_handler.compute_event_context(event)
context = EventContext.for_outlier()
stream_id = await self._federation_event_handler.persist_events_and_notify(
event.room_id, [(event, context)]
)
@ -814,7 +814,7 @@ class FederationHandler(BaseHandler):
)
)
context = await self.state_handler.compute_event_context(event)
context = EventContext.for_outlier()
await self._federation_event_handler.persist_events_and_notify(
event.room_id, [(event, context)]
)
@ -843,7 +843,7 @@ class FederationHandler(BaseHandler):
await self.federation_client.send_leave(host_list, event)
context = await self.state_handler.compute_event_context(event)
context = EventContext.for_outlier()
stream_id = await self._federation_event_handler.persist_events_and_notify(
event.room_id, [(event, context)]
)
@ -1115,8 +1115,7 @@ class FederationHandler(BaseHandler):
events_to_context = {}
for e in itertools.chain(auth_events, state):
e.internal_metadata.outlier = True
ctx = await self.state_handler.compute_event_context(e)
events_to_context[e.event_id] = ctx
events_to_context[e.event_id] = EventContext.for_outlier()
event_map = {
e.event_id: e for e in itertools.chain(auth_events, state, [event])

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@ -1221,7 +1221,7 @@ class FederationEventHandler:
async def prep(ev_info: _NewEventInfo) -> EventContext:
event = ev_info.event
with nested_logging_context(suffix=event.event_id):
res = await self._state_handler.compute_event_context(event)
res = EventContext.for_outlier()
res = await self._check_event_auth(
origin,
event,
@ -1540,10 +1540,7 @@ class FederationEventHandler:
event.event_id,
auth_event.event_id,
)
missing_auth_event_context = (
await self._state_handler.compute_event_context(auth_event)
)
missing_auth_event_context = EventContext.for_outlier()
missing_auth_event_context = await self._check_event_auth(
origin,
auth_event,

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@ -263,7 +263,9 @@ class StateHandler:
async def compute_event_context(
self, event: EventBase, old_state: Optional[Iterable[EventBase]] = None
) -> EventContext:
"""Build an EventContext structure for the event.
"""Build an EventContext structure for a non-outlier event.
(for an outlier, call EventContext.for_outlier directly)
This works out what the current state should be for the event, and
generates a new state group if necessary.
@ -278,35 +280,7 @@ class StateHandler:
The event context.
"""
if event.internal_metadata.is_outlier():
# If this is an outlier, then we know it shouldn't have any current
# state. Certainly store.get_current_state won't return any, and
# persisting the event won't store the state group.
# FIXME: why do we populate current_state_ids? I thought the point was
# that we weren't supposed to have any state for outliers?
if old_state:
prev_state_ids = {(s.type, s.state_key): s.event_id for s in old_state}
if event.is_state():
current_state_ids = dict(prev_state_ids)
key = (event.type, event.state_key)
current_state_ids[key] = event.event_id
else:
current_state_ids = prev_state_ids
else:
current_state_ids = {}
prev_state_ids = {}
# We don't store state for outliers, so we don't generate a state
# group for it.
context = EventContext.with_state(
state_group=None,
state_group_before_event=None,
current_state_ids=current_state_ids,
prev_state_ids=prev_state_ids,
)
return context
assert not event.internal_metadata.is_outlier()
#
# first of all, figure out the state before the event