Prevent a sync request from removing a user's busy presence status (#12213)

In trying to use the MSC3026 busy presence status, the user's status
would be set back to 'online' next time they synced. This change makes
it so that syncing does not affect a user's presence status if it
is currently set to 'busy': it must be removed through the presence
API.

The MSC defers to implementations on the behaviour of busy presence,
so this ought to remain compatible with the MSC.

Author: dbkr

changelog.d/12213.bugfix

@@ -0,0 +1 @@
+Prevent a sync request from removing a user's busy presence status.

synapse/handlers/events.py

@@ -16,7 +16,7 @@
 import random
 from typing import TYPE_CHECKING, Iterable, List, Optional
 
-from synapse.api.constants import EduTypes, EventTypes, Membership
+from synapse.api.constants import EduTypes, EventTypes, Membership, PresenceState
 from synapse.api.errors import AuthError, SynapseError
 from synapse.events import EventBase
 from synapse.events.utils import SerializeEventConfig
@@ -67,7 +67,9 @@ async def get_stream(
         presence_handler = self.hs.get_presence_handler()
 
         context = await presence_handler.user_syncing(
-            auth_user_id, affect_presence=affect_presence
+            auth_user_id,
+            affect_presence=affect_presence,
+            presence_state=PresenceState.ONLINE,
         )
         with context:
             if timeout:

synapse/handlers/presence.py

@@ -151,7 +151,7 @@ def __init__(self, hs: "HomeServer"):
 
     @abc.abstractmethod
     async def user_syncing(
-        self, user_id: str, affect_presence: bool
+        self, user_id: str, affect_presence: bool, presence_state: str
     ) -> ContextManager[None]:
         """Returns a context manager that should surround any stream requests
         from the user.
@@ -165,6 +165,7 @@ async def user_syncing(
             affect_presence: If false this function will be a no-op.
                 Useful for streams that are not associated with an actual
                 client that is being used by a user.
+            presence_state: The presence state indicated in the sync request
         """
 
     @abc.abstractmethod
@@ -228,6 +229,11 @@ async def current_state_for_users(
 
         return states
 
+    async def current_state_for_user(self, user_id: str) -> UserPresenceState:
+        """Get the current presence state for a user."""
+        res = await self.current_state_for_users([user_id])
+        return res[user_id]
+
     @abc.abstractmethod
     async def set_state(
         self,
@@ -461,7 +467,7 @@ def send_stop_syncing(self) -> None:
                 self.send_user_sync(user_id, False, last_sync_ms)
 
     async def user_syncing(
-        self, user_id: str, affect_presence: bool
+        self, user_id: str, affect_presence: bool, presence_state: str
     ) -> ContextManager[None]:
         """Record that a user is syncing.
 
@@ -471,6 +477,17 @@ async def user_syncing(
         if not affect_presence or not self._presence_enabled:
             return _NullContextManager()
 
+        prev_state = await self.current_state_for_user(user_id)
+        if prev_state != PresenceState.BUSY:
+            # We set state here but pass ignore_status_msg = True as we don't want to
+            # cause the status message to be cleared.
+            # Note that this causes last_active_ts to be incremented which is not
+            # what the spec wants: see comment in the BasePresenceHandler version
+            # of this function.
+            await self.set_state(
+                UserID.from_string(user_id), {"presence": presence_state}, True
+            )
+
         curr_sync = self._user_to_num_current_syncs.get(user_id, 0)
         self._user_to_num_current_syncs[user_id] = curr_sync + 1
 
@@ -942,7 +959,10 @@ async def bump_presence_active_time(self, user: UserID) -> None:
         await self._update_states([prev_state.copy_and_replace(**new_fields)])
 
     async def user_syncing(
-        self, user_id: str, affect_presence: bool = True
+        self,
+        user_id: str,
+        affect_presence: bool = True,
+        presence_state: str = PresenceState.ONLINE,
     ) -> ContextManager[None]:
         """Returns a context manager that should surround any stream requests
         from the user.
@@ -956,6 +976,7 @@ async def user_syncing(
             affect_presence: If false this function will be a no-op.
                 Useful for streams that are not associated with an actual
                 client that is being used by a user.
+            presence_state: The presence state indicated in the sync request
         """
         # Override if it should affect the user's presence, if presence is
         # disabled.
@@ -967,9 +988,25 @@ async def user_syncing(
             self.user_to_num_current_syncs[user_id] = curr_sync + 1
 
             prev_state = await self.current_state_for_user(user_id)
+
+            # If they're busy then they don't stop being busy just by syncing,
+            # so just update the last sync time.
+            if prev_state.state != PresenceState.BUSY:
+                # XXX: We set_state separately here and just update the last_active_ts above
+                # This keeps the logic as similar as possible between the worker and single
+                # process modes. Using set_state will actually cause last_active_ts to be
+                # updated always, which is not what the spec calls for, but synapse has done
+                # this for... forever, I think.
+                await self.set_state(
+                    UserID.from_string(user_id), {"presence": presence_state}, True
+                )
+                # Retrieve the new state for the logic below. This should come from the
+                # in-memory cache.
+                prev_state = await self.current_state_for_user(user_id)
+
+            # To keep the single process behaviour consistent with worker mode, run the
+            # same logic as `update_external_syncs_row`, even though it looks weird.
             if prev_state.state == PresenceState.OFFLINE:
-                # If they're currently offline then bring them online, otherwise
-                # just update the last sync times.
                 await self._update_states(
                     [
                         prev_state.copy_and_replace(
@@ -979,6 +1016,10 @@ async def user_syncing(
                         )
                     ]
                 )
+            # otherwise, set the new presence state & update the last sync time,
+            # but don't update last_active_ts as this isn't an indication that
+            # they've been active (even though it's probably been updated by
+            # set_state above)
             else:
                 await self._update_states(
                     [
@@ -1086,11 +1127,6 @@ async def update_external_syncs_clear(self, process_id: str) -> None:
             )
             self.external_process_last_updated_ms.pop(process_id, None)
 
-    async def current_state_for_user(self, user_id: str) -> UserPresenceState:
-        """Get the current presence state for a user."""
-        res = await self.current_state_for_users([user_id])
-        return res[user_id]
-
     async def _persist_and_notify(self, states: List[UserPresenceState]) -> None:
         """Persist states in the database, poke the notifier and send to
         interested remote servers

synapse/rest/client/sync.py

@@ -180,13 +180,10 @@ async def on_GET(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
 
         affect_presence = set_presence != PresenceState.OFFLINE
 
-        if affect_presence:
-            await self.presence_handler.set_state(
-                user, {"presence": set_presence}, True
-            )
-
         context = await self.presence_handler.user_syncing(
-            user.to_string(), affect_presence=affect_presence
+            user.to_string(),
+            affect_presence=affect_presence,
+            presence_state=set_presence,
         )
         with context:
             sync_result = await self.sync_handler.wait_for_sync_for_user(

tests/handlers/test_presence.py

@@ -657,6 +657,85 @@ def test_set_presence_with_status_msg_none(self):
         # Mark user as online and `status_msg = None`
         self._set_presencestate_with_status_msg(user_id, PresenceState.ONLINE, None)
 
+    def test_set_presence_from_syncing_not_set(self):
+        """Test that presence is not set by syncing if affect_presence is false"""
+        user_id = "@test:server"
+        status_msg = "I'm here!"
+
+        self._set_presencestate_with_status_msg(
+            user_id, PresenceState.UNAVAILABLE, status_msg
+        )
+
+        self.get_success(
+            self.presence_handler.user_syncing(user_id, False, PresenceState.ONLINE)
+        )
+
+        state = self.get_success(
+            self.presence_handler.get_state(UserID.from_string(user_id))
+        )
+        # we should still be unavailable
+        self.assertEqual(state.state, PresenceState.UNAVAILABLE)
+        # and status message should still be the same
+        self.assertEqual(state.status_msg, status_msg)
+
+    def test_set_presence_from_syncing_is_set(self):
+        """Test that presence is set by syncing if affect_presence is true"""
+        user_id = "@test:server"
+        status_msg = "I'm here!"
+
+        self._set_presencestate_with_status_msg(
+            user_id, PresenceState.UNAVAILABLE, status_msg
+        )
+
+        self.get_success(
+            self.presence_handler.user_syncing(user_id, True, PresenceState.ONLINE)
+        )
+
+        state = self.get_success(
+            self.presence_handler.get_state(UserID.from_string(user_id))
+        )
+        # we should now be online
+        self.assertEqual(state.state, PresenceState.ONLINE)
+
+    def test_set_presence_from_syncing_keeps_status(self):
+        """Test that presence set by syncing retains status message"""
+        user_id = "@test:server"
+        status_msg = "I'm here!"
+
+        self._set_presencestate_with_status_msg(
+            user_id, PresenceState.UNAVAILABLE, status_msg
+        )
+
+        self.get_success(
+            self.presence_handler.user_syncing(user_id, True, PresenceState.ONLINE)
+        )
+
+        state = self.get_success(
+            self.presence_handler.get_state(UserID.from_string(user_id))
+        )
+        # our status message should be the same as it was before
+        self.assertEqual(state.status_msg, status_msg)
+
+    def test_set_presence_from_syncing_keeps_busy(self):
+        """Test that presence set by syncing doesn't affect busy status"""
+        # while this isn't the default
+        self.presence_handler._busy_presence_enabled = True
+
+        user_id = "@test:server"
+        status_msg = "I'm busy!"
+
+        self._set_presencestate_with_status_msg(user_id, PresenceState.BUSY, status_msg)
+
+        self.get_success(
+            self.presence_handler.user_syncing(user_id, True, PresenceState.ONLINE)
+        )
+
+        state = self.get_success(
+            self.presence_handler.get_state(UserID.from_string(user_id))
+        )
+        # we should still be busy
+        self.assertEqual(state.state, PresenceState.BUSY)
+
     def _set_presencestate_with_status_msg(
         self, user_id: str, state: str, status_msg: Optional[str]
     ):