diff --git a/synapse/state.py b/synapse/state.py
index 8144fa02b4..081bc31bb5 100644
--- a/synapse/state.py
+++ b/synapse/state.py
@@ -19,6 +19,7 @@ from twisted.internet import defer
from synapse.util.logutils import log_function
from synapse.util.async import run_on_reactor
from synapse.api.constants import EventTypes
+from synapse.api.errors import AuthError
from synapse.events.snapshot import EventContext
from collections import namedtuple
@@ -36,12 +37,16 @@ def _get_state_key_from_event(event):
KeyStateTuple = namedtuple("KeyStateTuple", ("context", "type", "state_key"))
+AuthEventTypes = (EventTypes.Create, EventTypes.Member, EventTypes.PowerLevels,)
+
+
class StateHandler(object):
""" Responsible for doing state conflict resolution.
"""
def __init__(self, hs):
self.store = hs.get_datastore()
+ self.hs = hs
@defer.inlineCallbacks
def get_current_state(self, room_id, event_type=None, state_key=""):
@@ -210,64 +215,93 @@ class StateHandler(object):
else:
prev_states = []
+ auth_events = {
+ k: e for k, e in unconflicted_state.items()
+ if k[0] in AuthEventTypes
+ }
+
try:
- new_state = {}
- new_state.update(unconflicted_state)
- for key, events in conflicted_state.items():
- new_state[key] = self._resolve_state_events(events)
+ resolved_state = self._resolve_state_events(
+ conflicted_state, auth_events
+ )
except:
logger.exception("Failed to resolve state")
raise
- defer.returnValue((None, new_state, prev_states))
-
- def _get_power_level_from_event_state(self, event, user_id):
- if hasattr(event, "old_state_events") and event.old_state_events:
- key = (EventTypes.PowerLevels, "", )
- power_level_event = event.old_state_events.get(key)
- level = None
- if power_level_event:
- level = power_level_event.content.get("users", {}).get(
- user_id
- )
- if not level:
- level = power_level_event.content.get("users_default", 0)
+ new_state = unconflicted_state
+ new_state.update(resolved_state)
- return level
- else:
- return 0
+ defer.returnValue((None, new_state, prev_states))
@log_function
- def _resolve_state_events(self, events):
- curr_events = events
-
- new_powers = [
- self._get_power_level_from_event_state(e, e.user_id)
- for e in curr_events
- ]
-
- new_powers = [
- int(p) if p else 0 for p in new_powers
- ]
+ def _resolve_state_events(self, conflicted_state, auth_events):
+ """ This is where we actually decide which of the conflicted state to
+ use.
+
+ We resolve conflicts in the following order:
+ 1. power levels
+ 2. memberships
+ 3. other events.
+ """
+ resolved_state = {}
+ power_key = (EventTypes.PowerLevels, "")
+ if power_key in conflicted_state.items():
+ power_levels = conflicted_state[power_key]
+ resolved_state[power_key] = self._resolve_auth_events(power_levels)
+
+ auth_events.update(resolved_state)
+
+ for key, events in conflicted_state.items():
+ if key[0] == EventTypes.Member:
+ resolved_state[key] = self._resolve_auth_events(
+ events,
+ auth_events
+ )
- max_power = max(new_powers)
+ auth_events.update(resolved_state)
- curr_events = [
- z[0] for z in zip(curr_events, new_powers)
- if z[1] == max_power
- ]
+ for key, events in conflicted_state.items():
+ if key not in resolved_state:
+ resolved_state[key] = self._resolve_normal_events(
+ events, auth_events
+ )
- if not curr_events:
- raise RuntimeError("Max didn't get a max?")
- elif len(curr_events) == 1:
- return curr_events[0]
-
- # TODO: For now, just choose the one with the largest event_id.
- return (
- sorted(
- curr_events,
- key=lambda e: hashlib.sha1(
- e.event_id + e.user_id + e.room_id + e.type
- ).hexdigest()
- )[0]
- )
+ return resolved_state
+
+ def _resolve_auth_events(self, events, auth_events):
+ reverse = [i for i in reversed(self._ordered_events(events))]
+
+ auth_events = dict(auth_events)
+
+ prev_event = reverse[0]
+ for event in reverse[1:]:
+ auth_events[(prev_event.type, prev_event.state_key)] = prev_event
+ try:
+ # FIXME: hs.get_auth() is bad style, but we need to do it to
+ # get around circular deps.
+ self.hs.get_auth().check(event, auth_events)
+ prev_event = event
+ except AuthError:
+ return prev_event
+
+ return event
+
+ def _resolve_normal_events(self, events, auth_events):
+ for event in self._ordered_events(events):
+ try:
+ # FIXME: hs.get_auth() is bad style, but we need to do it to
+ # get around circular deps.
+ self.hs.get_auth().check(event, auth_events)
+ return event
+ except AuthError:
+ pass
+
+ # Use the last event (the one with the least depth) if they all fail
+ # the auth check.
+ return event
+
+ def _ordered_events(self, events):
+ def key_func(e):
+ return -int(e.depth), hashlib.sha1(e.event_id).hexdigest()
+
+ return sorted(events, key=key_func)
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