Rename event_map to unpersisted_events (#13603)

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David Robertson 2022-08-24 21:06:31 +01:00 committed by GitHub
parent 1a209efdb2
commit c406d50d2d
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2 changed files with 37 additions and 31 deletions

1
changelog.d/13603.misc Normal file
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@ -0,0 +1 @@
Rename `event_map` to `unpersisted_events` when computing the auth differences.

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@ -271,40 +271,41 @@ async def _get_power_level_for_sender(
async def _get_auth_chain_difference(
room_id: str,
state_sets: Sequence[Mapping[Any, str]],
event_map: Dict[str, EventBase],
unpersisted_events: Dict[str, EventBase],
state_res_store: StateResolutionStore,
) -> Set[str]:
"""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.
that only appear in some, but not all of the auth chains.
Args:
state_sets
event_map
state_res_store
state_sets: The input state sets we are trying to resolve across.
unpersisted_events: A map from event ID to EventBase containing all unpersisted
events involved in this resolution.
state_res_store:
Returns:
Set of event IDs
The auth difference of the given state sets, as a set of event IDs.
"""
# The `StateResolutionStore.get_auth_chain_difference` function assumes that
# all events passed to it (and their auth chains) have been persisted
# previously. This is not the case for any events in the `event_map`, and so
# we need to manually handle those events.
# previously. We need to manually handle any other events that are yet to be
# persisted.
#
# We do this by:
# 1. calculating the auth chain difference for the state sets based on the
# events in `event_map` alone
# 2. replacing any events in the state_sets that are also in `event_map`
# with their auth events (recursively), and then calling
# `store.get_auth_chain_difference` as normal
# 3. adding the results of 1 and 2 together.
# We do this in three steps:
# 1. Compute the set of unpersisted events belonging to the auth difference.
# 2. Replacing any unpersisted events in the state_sets with their auth events,
# recursively, until the state_sets contain only persisted events.
# Then we call `store.get_auth_chain_difference` as normal, which computes
# the set of persisted events belonging to the auth difference.
# 3. Adding the results of 1 and 2 together.
# Map from event ID in `event_map` to their auth event IDs, and their auth
# event IDs if they appear in the `event_map`. This is the intersection of
# the event's auth chain with the events in the `event_map` *plus* their
# Map from event ID in `unpersisted_events` to their auth event IDs, and their auth
# event IDs if they appear in the `unpersisted_events`. This is the intersection of
# the event's auth chain with the events in `unpersisted_events` *plus* their
# auth event IDs.
events_to_auth_chain: Dict[str, Set[str]] = {}
for event in event_map.values():
for event in unpersisted_events.values():
chain = {event.event_id}
events_to_auth_chain[event.event_id] = chain
@ -312,16 +313,16 @@ async def _get_auth_chain_difference(
while to_search:
for auth_id in to_search.pop().auth_event_ids():
chain.add(auth_id)
auth_event = event_map.get(auth_id)
auth_event = unpersisted_events.get(auth_id)
if auth_event:
to_search.append(auth_event)
# We now a) calculate the auth chain difference for the unpersisted events
# and b) work out the state sets to pass to the store.
# We now 1) calculate the auth chain difference for the unpersisted events
# and 2) work out the state sets to pass to the store.
#
# Note: If the `event_map` is empty (which is the common case), we can do a
# Note: If there are no `unpersisted_events` (which is the common case), we can do a
# much simpler calculation.
if event_map:
if unpersisted_events:
# The list of state sets to pass to the store, where each state set is a set
# of the event ids making up the state. This is similar to `state_sets`,
# except that (a) we only have event ids, not the complete
@ -344,14 +345,18 @@ async def _get_auth_chain_difference(
for event_id in state_set.values():
event_chain = events_to_auth_chain.get(event_id)
if event_chain is not None:
# We have an event in `event_map`. We add all the auth
# events that it references (that aren't also in `event_map`).
set_ids.update(e for e in event_chain if e not in event_map)
# We have an unpersisted event. We add all the auth
# events that it references which are also unpersisted.
set_ids.update(
e for e in event_chain if e not in unpersisted_events
)
# We also add the full chain of unpersisted event IDs
# referenced by this state set, so that we can work out the
# auth chain difference of the unpersisted events.
unpersisted_ids.update(e for e in event_chain if e in event_map)
unpersisted_ids.update(
e for e in event_chain if e in unpersisted_events
)
else:
set_ids.add(event_id)
@ -361,15 +366,15 @@ async def _get_auth_chain_difference(
union = unpersisted_set_ids[0].union(*unpersisted_set_ids[1:])
intersection = unpersisted_set_ids[0].intersection(*unpersisted_set_ids[1:])
difference_from_event_map: Collection[str] = union - intersection
auth_difference_unpersisted_part: Collection[str] = union - intersection
else:
difference_from_event_map = ()
auth_difference_unpersisted_part = ()
state_sets_ids = [set(state_set.values()) for state_set in state_sets]
difference = await state_res_store.get_auth_chain_difference(
room_id, state_sets_ids
)
difference.update(difference_from_event_map)
difference.update(auth_difference_unpersisted_part)
return difference