diff --git a/synapse/events/snapshot.py b/synapse/events/snapshot.py
index 0f3c5989cb..64e898f40c 100644
--- a/synapse/events/snapshot.py
+++ b/synapse/events/snapshot.py
@@ -48,10 +48,21 @@ class EventContext:
Note that this is a private attribute: it should be accessed via
the ``state_group`` property.
+ state_group_before_event: The ID of the state group representing the state
+ of the room before this event.
+
+ If this is a non-state event, this will be the same as ``state_group``. If
+ it's a state event, it will be the same as ``prev_group``.
+
+ If ``state_group`` is None (ie, the event is an outlier),
+ ``state_group_before_event`` will always also be ``None``.
+
prev_group: If it is known, ``state_group``'s prev_group. Note that this being
None does not necessarily mean that ``state_group`` does not have
a prev_group!
+ If the event is a state event, this is normally the same as ``prev_group``.
+
If ``state_group`` is None (ie, the event is an outlier), ``prev_group``
will always also be ``None``.
@@ -77,7 +88,8 @@ class EventContext:
``get_current_state_ids``. _AsyncEventContext impl calculates this
on-demand: it will be None until that happens.
- _prev_state_ids: The room state map, excluding this event. For a non-state
+ _prev_state_ids: The room state map, excluding this event - ie, the state
+ in ``state_group_before_event``. For a non-state
event, this will be the same as _current_state_events.
Note that it is a completely different thing to prev_group!
@@ -92,6 +104,7 @@ class EventContext:
rejected = attr.ib(default=False, type=Union[bool, str])
_state_group = attr.ib(default=None, type=Optional[int])
+ state_group_before_event = attr.ib(default=None, type=Optional[int])
prev_group = attr.ib(default=None, type=Optional[int])
delta_ids = attr.ib(default=None, type=Optional[Dict[Tuple[str, str], str]])
app_service = attr.ib(default=None, type=Optional[ApplicationService])
@@ -103,12 +116,18 @@ class EventContext:
@staticmethod
def with_state(
- state_group, current_state_ids, prev_state_ids, prev_group=None, delta_ids=None
+ state_group,
+ state_group_before_event,
+ current_state_ids,
+ prev_state_ids,
+ prev_group=None,
+ delta_ids=None,
):
return EventContext(
current_state_ids=current_state_ids,
prev_state_ids=prev_state_ids,
state_group=state_group,
+ state_group_before_event=state_group_before_event,
prev_group=prev_group,
delta_ids=delta_ids,
)
@@ -140,6 +159,7 @@ class EventContext:
"event_type": event.type,
"event_state_key": event.state_key if event.is_state() else None,
"state_group": self._state_group,
+ "state_group_before_event": self.state_group_before_event,
"rejected": self.rejected,
"prev_group": self.prev_group,
"delta_ids": _encode_state_dict(self.delta_ids),
@@ -165,6 +185,7 @@ class EventContext:
event_type=input["event_type"],
event_state_key=input["event_state_key"],
state_group=input["state_group"],
+ state_group_before_event=input["state_group_before_event"],
prev_group=input["prev_group"],
delta_ids=_decode_state_dict(input["delta_ids"]),
rejected=input["rejected"],
|
