From 3d3da2b4609d02bbbb276313fd6b2cc8069e213d Mon Sep 17 00:00:00 2001
From: Mark Haines <mark.haines@matrix.org>
Date: Tue, 1 Dec 2015 16:03:08 +0000
Subject: [PATCH] Only fire user_joined_room on the distributor if the user has
 actually joined the room

---
 synapse/handlers/room.py | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 023b4001b8..cb6ac37758 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -517,10 +517,12 @@ class RoomMemberHandler(BaseHandler):
                 do_auth=do_auth,
             )
 
-        user = UserID.from_string(event.user_id)
-        yield self.distributor.fire(
-            "user_joined_room", user=user, room_id=room_id
-        )
+        prev_state = context.current_state.get((event.type, event.state_key))
+        if not prev_state or prev_state.membership != Membership.JOIN:
+            user = UserID.from_string(event.user_id)
+            yield self.distributor.fire(
+                "user_joined_room", user=user, room_id=room_id
+            )
 
     @defer.inlineCallbacks
     def get_inviter(self, event):
-- 
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