From 2c2a42cc107fb02bbf7c8d4e6141cbe601221629 Mon Sep 17 00:00:00 2001
From: Eric Eastwood <erice@element.io>
Date: Tue, 5 Jul 2022 05:56:06 -0500
Subject: [PATCH] Fix application service not being able to join remote
 federated room without a profile set (#13131)

Fix https://github.com/matrix-org/synapse/issues/4778

Complement tests: https://github.com/matrix-org/complement/pull/399
---
 changelog.d/13131.bugfix        |  1 +
 synapse/handlers/room_member.py | 32 +++++++++++++++++++++++---------
 2 files changed, 24 insertions(+), 9 deletions(-)
 create mode 100644 changelog.d/13131.bugfix

diff --git a/changelog.d/13131.bugfix b/changelog.d/13131.bugfix
new file mode 100644
index 000000000..06602f03f
--- /dev/null
+++ b/changelog.d/13131.bugfix
@@ -0,0 +1 @@
+Fix application service not being able to join remote federated room without a profile set.
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 5648ab4bf..a1d8875dd 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -846,10 +846,17 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
 
                 content["membership"] = Membership.JOIN
 
-                profile = self.profile_handler
-                if not content_specified:
-                    content["displayname"] = await profile.get_displayname(target)
-                    content["avatar_url"] = await profile.get_avatar_url(target)
+                try:
+                    profile = self.profile_handler
+                    if not content_specified:
+                        content["displayname"] = await profile.get_displayname(target)
+                        content["avatar_url"] = await profile.get_avatar_url(target)
+                except Exception as e:
+                    logger.info(
+                        "Failed to get profile information while processing remote join for %r: %s",
+                        target,
+                        e,
+                    )
 
                 if requester.is_guest:
                     content["kind"] = "guest"
@@ -926,11 +933,18 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
 
                 content["membership"] = Membership.KNOCK
 
-                profile = self.profile_handler
-                if "displayname" not in content:
-                    content["displayname"] = await profile.get_displayname(target)
-                if "avatar_url" not in content:
-                    content["avatar_url"] = await profile.get_avatar_url(target)
+                try:
+                    profile = self.profile_handler
+                    if "displayname" not in content:
+                        content["displayname"] = await profile.get_displayname(target)
+                    if "avatar_url" not in content:
+                        content["avatar_url"] = await profile.get_avatar_url(target)
+                except Exception as e:
+                    logger.info(
+                        "Failed to get profile information while processing remote knock for %r: %s",
+                        target,
+                        e,
+                    )
 
                 return await self.remote_knock(
                     remote_room_hosts, room_id, target, content