From f987db5a3989b1da6eb004854591e719888691b9 Mon Sep 17 00:00:00 2001
From: Christoph Scholz <christoph.scholz@gmail.com>
Date: Mon, 18 Feb 2019 12:03:16 +0100
Subject: [PATCH] check if mod_mam is loaded before calling
 mod_mam:is_empty_for_room

---
 src/mod_muc_admin.erl | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/mod_muc_admin.erl b/src/mod_muc_admin.erl
index 087ea7196..494a4ef3f 100644
--- a/src/mod_muc_admin.erl
+++ b/src/mod_muc_admin.erl
@@ -839,7 +839,12 @@ decide_room(unused, {_Room_name, _Host, Room_pid}, ServerHost, Last_allowed) ->
 	    false
     end;
 decide_room(empty, {Room_name, Host, _Room_pid}, ServerHost, _Last_allowed) ->
-	mod_mam:is_empty_for_room(ServerHost, Room_name, Host).
+    case gen_mod:is_loaded(ServerHost, mod_mam) of
+        true ->
+        mod_mam:is_empty_for_room(ServerHost, Room_name, Host);
+        _ ->
+        false
+    end.
 
 seconds_to_days(S) ->
     S div (60*60*24).