From 0e64090732fd5de93488c5cb83771fa6451db93b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20Chrz=C4=85szcz?=
 <pawel.chrzaszcz@erlang-solutions.com>
Date: Thu, 7 Apr 2022 11:37:27 +0200
Subject: [PATCH] Get only existing subhosts for MAM MUC domain removal

Previously defaults were used even if MUC(Light) was not enabled.
---
 src/mam/mod_mam_muc_rdbms_arch.erl | 18 +++++++++++-------
 src/muc_light/mod_muc_light.erl    |  1 -
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/src/mam/mod_mam_muc_rdbms_arch.erl b/src/mam/mod_mam_muc_rdbms_arch.erl
index bf035b6061..9114fc63d3 100644
--- a/src/mam/mod_mam_muc_rdbms_arch.erl
+++ b/src/mam/mod_mam_muc_rdbms_arch.erl
@@ -327,13 +327,17 @@ remove_domain_trans(HostType, MucHost) ->
     mongoose_rdbms:execute_successfully(HostType, mam_muc_remove_domain_users, [MucHost]).
 
 get_subhosts(HostType, Domain) ->
-    MucHostPattern = gen_mod:get_module_opt(HostType, mod_muc, host,
-                                            mod_muc:default_host()),
-    LightHostPattern = gen_mod:get_module_opt(HostType, mod_muc_light, host,
-                                              mod_muc_light:default_host()),
-    MucHost = mongoose_subdomain_utils:get_fqdn(MucHostPattern, Domain),
-    LightHost = mongoose_subdomain_utils:get_fqdn(LightHostPattern, Domain),
-    lists:usort([MucHost, LightHost]).
+    lists:usort(
+      lists:flatmap(fun(Module) -> get_subhosts_for_module(HostType, Domain, Module) end,
+                    [mod_muc, mod_muc_light])).
+
+get_subhosts_for_module(HostType, Domain, Module) ->
+    case gen_mod:get_module_opts(HostType, Module) of
+        #{host := HostPattern} ->
+            [mongoose_subdomain_utils:get_fqdn(HostPattern, Domain)];
+        #{} ->
+            []
+    end.
 
 %% GDPR logic
 extract_gdpr_messages(HostType, SenderID) ->
diff --git a/src/muc_light/mod_muc_light.erl b/src/muc_light/mod_muc_light.erl
index a26f79be97..594e8d30e6 100644
--- a/src/muc_light/mod_muc_light.erl
+++ b/src/muc_light/mod_muc_light.erl
@@ -24,7 +24,6 @@
 -behaviour(mongoose_module_metrics).
 
 %% API
--export([default_host/0]).
 -export([server_host_to_muc_host/2]).
 -export([config_schema/1]).