From 07580e6787d1f68fe6f657c3eaeeb785c80ec6db Mon Sep 17 00:00:00 2001
From: Badlop <badlop@process-one.net>
Date: Thu, 19 Feb 2026 21:48:01 +0100
Subject: [PATCH] mod_mam: Allow backend modules to add fulltext namespace in
 Service Discovery

---
 src/mod_mam.erl        | 18 ++++++++++++------
 src/mod_mam_mnesia.erl |  4 ++++
 src/mod_mam_sql.erl    |  9 +++++++++
 src/mod_muc_room.erl   |  7 +++++--
 4 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/src/mod_mam.erl b/src/mod_mam.erl
index 49e780b48..b79966cb3 100644
--- a/src/mod_mam.erl
+++ b/src/mod_mam.erl
@@ -30,8 +30,8 @@
 -protocol({xep, 359, '0.7.0', '15.09', "complete", ""}).
 -protocol({xep, 424, '0.4.2', '24.02', "partial", "Tombstones not implemented"}).
 -protocol({xep, 425, '0.3.0', '24.06', "complete", ""}).
--protocol({xep, 441, '0.2.0', '15.06', "complete", ""}).
 -protocol({xep, 431, '0.2.0', '24.12', "complete", ""}).
+-protocol({xep, 441, '0.2.0', '15.06', "complete", ""}).
 
 -behaviour(gen_mod).
 
@@ -79,6 +79,7 @@
 -callback delete_old_messages(binary() | global,
 			      erlang:timestamp(),
 			      all | chat | groupchat) -> any().
+-callback additional_namespaces(binary()) -> [binary()].
 -callback extended_fields(binary()) -> [mam_query:property() | #xdata_field{}].
 -callback store(xmlel(), binary(), {binary(), binary()}, chat | groupchat,
 		jid(), binary(), recv | send, integer(), binary(),
@@ -627,12 +628,15 @@ parse_query(#mam_query{}, _Lang) ->
 
 disco_local_features({error, _Error} = Acc, _From, _To, _Node, _Lang) ->
     Acc;
-disco_local_features(Acc, _From, _To, <<"">>, _Lang) ->
+disco_local_features(Acc, _From, #jid{lserver = LServer} = _To, <<"">>, _Lang) ->
     Features = case Acc of
 		   {result, Fs} -> Fs;
 		   empty -> []
 	       end,
-    {result, [?NS_MESSAGE_RETRACT | Features]};
+    Mod = gen_mod:db_mod(LServer, ?MODULE),
+    AdditionalNamespaces = Mod:additional_namespaces(LServer),
+    Namespaces = [?NS_MESSAGE_RETRACT],
+    {result, lists:append([Namespaces, AdditionalNamespaces, Features])};
 disco_local_features(empty, _From, _To, _Node, Lang) ->
     Txt = ?T("No features available"),
     {error, xmpp:err_item_not_found(Txt, Lang)};
@@ -644,9 +648,11 @@ disco_sm_features(empty, From, To, Node, Lang) ->
 disco_sm_features({result, OtherFeatures},
 		  #jid{luser = U, lserver = S},
 		  #jid{luser = U, lserver = S}, <<"">>, _Lang) ->
-    {result, [?NS_MAM_TMP, ?NS_MAM_0, ?NS_MAM_1, ?NS_MAM_2, ?NS_SID_0,
-              ?NS_MESSAGE_RETRACT |
-	      OtherFeatures]};
+    Mod = gen_mod:db_mod(S, ?MODULE),
+    AdditionalNamespaces = Mod:additional_namespaces(S),
+    Namespaces = [?NS_MAM_TMP, ?NS_MAM_0, ?NS_MAM_1, ?NS_MAM_2, ?NS_SID_0,
+              ?NS_MESSAGE_RETRACT],
+    {result, lists:append([Namespaces, AdditionalNamespaces, OtherFeatures])};
 disco_sm_features(Acc, _From, _To, _Node, _Lang) ->
     Acc.
 
diff --git a/src/mod_mam_mnesia.erl b/src/mod_mam_mnesia.erl
index f268e327e..41f41f5d0 100644
--- a/src/mod_mam_mnesia.erl
+++ b/src/mod_mam_mnesia.erl
@@ -29,6 +29,7 @@
 
 %% API
 -export([init/2, remove_user/2, remove_room/3, delete_old_messages/3,
+         additional_namespaces/1,
 	 extended_fields/1, store/10, write_prefs/4, get_prefs/2, select/6,
          remove_from_archive/3,
 	 is_empty_for_user/2, is_empty_for_room/3, delete_old_messages_batch/5,
@@ -189,6 +190,9 @@ delete_old_messages_batch(LServer, TimeStamp, Type, Batch, LastUS) ->
 	    {error, Err}
     end.
 
+additional_namespaces(_) ->
+    [].
+
 extended_fields(_) ->
     [].
 
diff --git a/src/mod_mam_sql.erl b/src/mod_mam_sql.erl
index d4788a86e..7c247e2a6 100644
--- a/src/mod_mam_sql.erl
+++ b/src/mod_mam_sql.erl
@@ -30,6 +30,7 @@
 
 %% API
 -export([init/2, remove_user/2, remove_room/3, delete_old_messages/3,
+         additional_namespaces/1,
 	 extended_fields/1, store/10, write_prefs/4, get_prefs/2, select/7, export/1, remove_from_archive/3,
 	 is_empty_for_user/2, is_empty_for_room/3, select_with_mucsub/6,
 	 delete_old_messages_batch/4, count_messages_to_delete/3]).
@@ -283,6 +284,14 @@ delete_old_messages(ServerHost, TimeStamp, Type) ->
     end,
     ok.
 
+additional_namespaces(LServer) ->
+    case ejabberd_option:sql_type(LServer) of
+	mysql ->
+	    [?NS_MAM_FULLTEXT_0];
+	_ ->
+	    []
+    end.
+
 extended_fields(LServer) ->
     case ejabberd_option:sql_type(LServer) of
 	mysql ->
diff --git a/src/mod_muc_room.erl b/src/mod_muc_room.erl
index 798a5bfa9..113d17327 100644
--- a/src/mod_muc_room.erl
+++ b/src/mod_muc_room.erl
@@ -4496,10 +4496,13 @@ make_disco_info(From, StateData) ->
 	       true -> [?NS_HATS];
 	       false -> []
 	   end
-	++ case {gen_mod:is_loaded(StateData#state.server_host, mod_mam),
+	++ case {gen_mod:is_loaded(ServerHost, mod_mam),
 		 Config#config.mam} of
 	       {true, true} ->
-		   [?NS_MAM_TMP, ?NS_MAM_0, ?NS_MAM_1, ?NS_MAM_2, ?NS_SID_0];
+                   Mod = gen_mod:db_mod(ServerHost, mod_mam),
+                   AdditionalNamespaces = Mod:additional_namespaces(ServerHost),
+		   [?NS_MAM_TMP, ?NS_MAM_0, ?NS_MAM_1, ?NS_MAM_2, ?NS_SID_0
+                    | AdditionalNamespaces];
 	       _ ->
 		   []
 	   end,