From 07dfe148de2fbc6eb22be662ed8216a6e11f6811 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>
Date: Thu, 31 Jan 2019 18:30:40 +0000
Subject: [PATCH] Add some debug for membership syncing issues (#4538)

I can't figure out what's going on with #4422 and #4436; perhaps this will help.
---
 changelog.d/4538.misc    |  1 +
 synapse/handlers/sync.py | 13 +++++++++++--
 2 files changed, 12 insertions(+), 2 deletions(-)
 create mode 100644 changelog.d/4538.misc

diff --git a/changelog.d/4538.misc b/changelog.d/4538.misc
new file mode 100644
index 000000000..dbc878b09
--- /dev/null
+++ b/changelog.d/4538.misc
@@ -0,0 +1 @@
+Add some debug for membership syncing issues
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 28857bfc1..bd97241ab 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -895,14 +895,17 @@ class SyncHandler(object):
         Returns:
             Deferred(SyncResult)
         """
-        logger.info("Calculating sync response for %r", sync_config.user)
-
         # NB: The now_token gets changed by some of the generate_sync_* methods,
         # this is due to some of the underlying streams not supporting the ability
         # to query up to a given point.
         # Always use the `now_token` in `SyncResultBuilder`
         now_token = yield self.event_sources.get_current_token()
 
+        logger.info(
+            "Calculating sync response for %r between %s and %s",
+            sync_config.user, since_token, now_token,
+        )
+
         user_id = sync_config.user.to_string()
         app_service = self.store.get_app_service_by_user_id(user_id)
         if app_service:
@@ -1390,6 +1393,12 @@ class SyncHandler(object):
         room_entries = []
         invited = []
         for room_id, events in iteritems(mem_change_events_by_room_id):
+            logger.info(
+                "Membership changes in %s: [%s]",
+                room_id,
+                ", ".join(("%s (%s)" % (e.event_id, e.membership) for e in events)),
+            )
+
             non_joins = [e for e in events if e.membership != Membership.JOIN]
             has_join = len(non_joins) != len(events)