From 94700e55fa93653d678fb5e27322fde4c0a15f3d Mon Sep 17 00:00:00 2001
From: Michael Telatynski <7t3chguy@gmail.com>
Date: Wed, 13 Jun 2018 10:31:01 +0100
Subject: [PATCH 1/2] if inviter_display_name == ""||None then default to
 inviter MXID to prevent email invite from "None"

---
 synapse/handlers/room_member.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index b3f979b24..1b8dfa825 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -565,6 +565,10 @@ class RoomMemberHandler(BaseHandler):
             inviter_display_name = member_event.content.get("displayname", "")
             inviter_avatar_url = member_event.content.get("avatar_url", "")
 
+        # if user has no display name, default to their MXID
+        if not inviter_display_name:
+            inviter_display_name = user.to_string()
+
         canonical_room_alias = ""
         canonical_alias_event = room_state.get((EventTypes.CanonicalAlias, ""))
         if canonical_alias_event:

From 38eaa5280d49df8d0e52f93693a576b7e936bde5 Mon Sep 17 00:00:00 2001
From: Michael Telatynski <7t3chguy@gmail.com>
Date: Tue, 24 Jul 2018 17:25:42 +0100
Subject: [PATCH 2/2] add changelog entry for PR#3391

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>
---
 changelog.d/3391.bugfix | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changelog.d/3391.bugfix

diff --git a/changelog.d/3391.bugfix b/changelog.d/3391.bugfix
new file mode 100644
index 000000000..88eeb50df
--- /dev/null
+++ b/changelog.d/3391.bugfix
@@ -0,0 +1 @@
+Default inviter_display_name to mxid for email invites
\ No newline at end of file