Add/improve type specs

11 files changed, 101 insertions, 47 deletions

diff --git a/src/ejabberd_captcha.erl b/src/ejabberd_captcha.erl
index cd07709a..02cf2659 100644
--- a/src/ejabberd_captcha.erl
+++ b/src/ejabberd_captcha.erl
@@ -52,6 +52,7 @@
 
 -type image_error() :: efbig | enodata | limit | malformed_image | timeout.
 -type priority() :: neg_integer().
+-type callback() :: fun((captcha_succeed | captcha_failed) -> any()).
 
 -record(state, {limits = treap:empty() :: treap:treap(),
 		enabled = false :: boolean()}).
@@ -84,8 +85,9 @@ mk_field(Type, Var, Value) ->
     #xdata_field{type = Type, var = Var, values = [Value]}.
 
 -spec create_captcha(binary(), jid(), jid(),
-                     binary(), any(), any()) -> {error, image_error()} |
-                                                {ok, binary(), [text()], [xmpp_element()]}.
+                     binary(), any(),
+		     callback() | term()) -> {error, image_error()} |
+					     {ok, binary(), [text()], [xmpp_element()]}.
 create_captcha(SID, From, To, Lang, Limiter, Args) ->
     case create_image(Limiter) of
       {ok, Type, Key, Image} ->
@@ -607,7 +609,9 @@ clean_treap(Treap, CleanPriority) ->
 	  end
     end.
 
--spec callback(captcha_succeed | captcha_failed, pid(), term()) -> any().
+-spec callback(captcha_succeed | captcha_failed,
+	       pid() | undefined,
+	       callback() | term()) -> any().
 callback(Result, _Pid, F) when is_function(F) ->
     F(Result);
 callback(Result, Pid, Args) when is_pid(Pid) ->
diff --git a/src/mod_avatar.erl b/src/mod_avatar.erl
index 73b89af6..8edcf323 100644
--- a/src/mod_avatar.erl
+++ b/src/mod_avatar.erl
@@ -68,6 +68,7 @@ depends(_Host, _Opts) ->
 %%%===================================================================
 %%% Hooks
 %%%===================================================================
+-spec pubsub_publish_item(binary(), binary(), jid(), jid(), binary(), [xmlel()]) -> ok.
 pubsub_publish_item(LServer, ?NS_AVATAR_METADATA,
 		    #jid{luser = LUser, lserver = LServer} = From,
 		    #jid{luser = LUser, lserver = LServer} = Host,
diff --git a/src/mod_block_strangers.erl b/src/mod_block_strangers.erl
index 5f59978a..0fc83eab 100644
--- a/src/mod_block_strangers.erl
+++ b/src/mod_block_strangers.erl
@@ -40,6 +40,8 @@
 
 -define(SETS, gb_sets).
 
+-type c2s_state() :: ejabberd_c2s:state().
+
 %%%===================================================================
 %%% Callbacks and hooks
 %%%===================================================================
@@ -62,6 +64,8 @@ stop(Host) ->
 reload(_Host, _NewOpts, _OldOpts) ->
     ok.
 
+-spec filter_packet({stanza(), c2s_state()}) -> {stanza(), c2s_state()} |
+						{stop, {drop, c2s_state()}}.
 filter_packet({#message{from = From} = Msg, State} = Acc) ->
     LFrom = jid:tolower(From),
     LBFrom = jid:remove_resource(LFrom),
@@ -80,12 +84,14 @@ filter_packet({#message{from = From} = Msg, State} = Acc) ->
 filter_packet(Acc) ->
     Acc.
 
+-spec filter_offline_msg({_, message()}) -> {_, message()} | {stop, {drop, message()}}.
 filter_offline_msg({_Action, #message{} = Msg} = Acc) ->
     case check_message(Msg) of
 	allow -> Acc;
 	deny -> {stop, {drop, Msg}}
     end.
 
+-spec filter_subscription(boolean(), presence()) -> boolean() | {stop, false}.
 filter_subscription(Acc, #presence{meta = #{captcha := passed}}) ->
     Acc;
 filter_subscription(Acc, #presence{from = From, to = To, lang = Lang,
@@ -136,6 +142,7 @@ filter_subscription(Acc, #presence{from = From, to = To, lang = Lang,
 filter_subscription(Acc, _) ->
     Acc.
 
+-spec handle_captcha_result(captcha_succeed | captcha_failed, presence()) -> ok.
 handle_captcha_result(captcha_succeed, Pres) ->
     Pres1 = xmpp:put_meta(Pres, captcha, passed),
     ejabberd_router:route(Pres1);
@@ -146,6 +153,7 @@ handle_captcha_result(captcha_failed, #presence{lang = Lang} = Pres) ->
 %%%===================================================================
 %%% Internal functions
 %%%===================================================================
+-spec check_message(message()) -> allow | deny.
 check_message(#message{from = From, to = To, lang = Lang} = Msg) ->
     LServer = To#jid.lserver,
     case need_check(Msg) of
@@ -222,6 +230,7 @@ check_subscription(From, To) ->
 	    true
     end.
 
+-spec sets_bare_member(ljid(), ?SETS:set()) -> boolean().
 sets_bare_member({U, S, <<"">>} = LBJID, Set) ->
     case ?SETS:next(?SETS:iterator_from(LBJID, Set)) of
         {{U, S, _}, _} -> true;
diff --git a/src/mod_blocking.erl b/src/mod_blocking.erl
index 233ce95a..64687bb3 100644
--- a/src/mod_blocking.erl
+++ b/src/mod_blocking.erl
@@ -258,6 +258,7 @@ process_get(#iq{from = #jid{luser = LUser, lserver = LServer}} = IQ) ->
 	    err_db_failure(IQ)
     end.
 
+-spec err_db_failure(iq()) -> iq().
 err_db_failure(#iq{lang = Lang} = IQ) ->
     Txt = ?T("Database failure"),
     xmpp:make_error(IQ, xmpp:err_internal_server_error(Txt, Lang)).
diff --git a/src/mod_caps.erl b/src/mod_caps.erl
index f1fc0e8f..ca126919 100644
--- a/src/mod_caps.erl
+++ b/src/mod_caps.erl
@@ -60,6 +60,8 @@
 
 -record(state, {host = <<"">> :: binary()}).
 
+-type digest_type() :: md5 | sha | sha224 | sha256 | sha384 | sha512.
+
 -callback init(binary(), gen_mod:opts()) -> any().
 -callback import(binary(), {binary(), binary()}, [binary() | pos_integer()]) -> ok.
 -callback caps_read(binary(), {binary(), binary()}) ->
@@ -416,19 +418,18 @@ make_my_disco_hash(Host) ->
       _Err -> <<"">>
     end.
 
--type digest_type() :: md5 | sha | sha224 | sha256 | sha384 | sha512.
 -spec compute_disco_hash(disco_info(), digest_type()) -> binary().
 compute_disco_hash(DiscoInfo, Algo) ->
     Concat = list_to_binary([concat_identities(DiscoInfo),
                              concat_features(DiscoInfo), concat_info(DiscoInfo)]),
     base64:encode(case Algo of
-                           md5 -> erlang:md5(Concat);
-                           sha -> crypto:hash(sha, Concat);
-                           sha224 -> crypto:hash(sha224, Concat);
-                           sha256 -> crypto:hash(sha256, Concat);
-                           sha384 -> crypto:hash(sha384, Concat);
-                           sha512 -> crypto:hash(sha512, Concat)
-                       end).
+		      md5 -> erlang:md5(Concat);
+		      sha -> crypto:hash(sha, Concat);
+		      sha224 -> crypto:hash(sha224, Concat);
+		      sha256 -> crypto:hash(sha256, Concat);
+		      sha384 -> crypto:hash(sha384, Concat);
+		      sha512 -> crypto:hash(sha512, Concat)
+		  end).
 
 -spec check_hash(caps(), disco_info()) -> boolean().
 check_hash(Caps, DiscoInfo) ->
diff --git a/src/mod_configure.erl b/src/mod_configure.erl
index ebdfadee..3c3381d7 100644
--- a/src/mod_configure.erl
+++ b/src/mod_configure.erl
@@ -119,8 +119,10 @@ depends(_Host, _Opts) ->
 	[<<"http:">>, <<"jabber.org">>, <<"protocol">>,
 	 <<"admin">>, Sub]).
 
+-spec tokenize(binary()) -> [binary()].
 tokenize(Node) -> str:tokens(Node, <<"/#">>).
 
+-spec get_sm_identity([identity()], jid(), jid(), binary(), binary()) -> [identity()].
 get_sm_identity(Acc, _From, _To, Node, Lang) ->
     case Node of
       <<"config">> ->
@@ -128,6 +130,7 @@ get_sm_identity(Acc, _From, _To, Node, Lang) ->
       _ -> Acc
     end.
 
+-spec get_local_identity([identity()], jid(), jid(), binary(), binary()) -> [identity()].
 get_local_identity(Acc, _From, _To, Node, Lang) ->
     LNode = tokenize(Node),
     case LNode of
@@ -190,6 +193,8 @@ get_local_identity(Acc, _From, _To, Node, Lang) ->
 	  allow -> {result, Feats}
 	end).
 
+-spec get_sm_features(mod_disco:features_acc(), jid(), jid(),
+		      binary(), binary()) -> mod_disco:features_acc().
 get_sm_features(Acc, From,
 		#jid{lserver = LServer} = _To, Node, Lang) ->
     case gen_mod:is_loaded(LServer, mod_adhoc) of
@@ -202,6 +207,8 @@ get_sm_features(Acc, From,
 	  end
     end.
 
+-spec get_local_features(mod_disco:features_acc(), jid(), jid(),
+			 binary(), binary()) -> mod_disco:features_acc().
 get_local_features(Acc, From,
 		   #jid{lserver = LServer} = _To, Node, Lang) ->
     case gen_mod:is_loaded(LServer, mod_adhoc) of
@@ -264,10 +271,8 @@ get_local_features(Acc, From,
     end.
 
 %%%-----------------------------------------------------------------------
--spec adhoc_sm_items(empty | {error, stanza_error()} | {result, [disco_item()]},
-		     jid(), jid(), binary()) -> {error, stanza_error()} |
-						{result, [disco_item()]} |
-						empty.
+-spec adhoc_sm_items(mod_disco:items_acc(),
+		     jid(), jid(), binary()) -> mod_disco:items_acc().
 adhoc_sm_items(Acc, From, #jid{lserver = LServer} = To,
 	       Lang) ->
     case acl:match_rule(LServer, configure, From) of
@@ -283,7 +288,8 @@ adhoc_sm_items(Acc, From, #jid{lserver = LServer} = To,
     end.
 
 %%%-----------------------------------------------------------------------
-
+-spec get_sm_items(mod_disco:items_acc(), jid(), jid(),
+		   binary(), binary()) -> mod_disco:items_acc().
 get_sm_items(Acc, From,
 	     #jid{user = User, server = Server, lserver = LServer} =
 		 To,
@@ -309,6 +315,7 @@ get_sm_items(Acc, From,
 	  end
     end.
 
+-spec get_user_resources(binary(), binary()) -> [disco_item()].
 get_user_resources(User, Server) ->
     Rs = ejabberd_sm:get_user_resources(User, Server),
     lists:map(fun (R) ->
@@ -319,10 +326,8 @@ get_user_resources(User, Server) ->
 
 %%%-----------------------------------------------------------------------
 
--spec adhoc_local_items(empty | {error, stanza_error()} | {result, [disco_item()]},
-			jid(), jid(), binary()) -> {error, stanza_error()} |
-						   {result, [disco_item()]} |
-						   empty.
+-spec adhoc_local_items(mod_disco:items_acc(),
+			jid(), jid(), binary()) -> mod_disco:items_acc().
 adhoc_local_items(Acc, From,
 		  #jid{lserver = LServer, server = Server} = To, Lang) ->
     case acl:match_rule(LServer, configure, From) of
@@ -336,7 +341,7 @@ adhoc_local_items(Acc, From,
 					      <<"">>, Server, Lang),
 	  Nodes1 = lists:filter(
 		     fun (#disco_item{node = Nd}) ->
-			     F = get_local_features([], From, To, Nd, Lang),
+			     F = get_local_features(empty, From, To, Nd, Lang),
 			     case F of
 				 {result, [?NS_COMMANDS]} -> true;
 				 _ -> false
@@ -347,6 +352,8 @@ adhoc_local_items(Acc, From,
       _ -> Acc
     end.
 
+-spec recursively_get_local_items(global | vhost, binary(), binary(),
+				  binary(), binary()) -> [disco_item()].
 recursively_get_local_items(_PermLev, _LServer,
 			    <<"online users">>, _Server, _Lang) ->
     [];
@@ -376,6 +383,7 @@ recursively_get_local_items(PermLev, LServer, Node,
 	end,
 	Items)).
 
+-spec get_permission_level(jid()) -> global | vhost.
 get_permission_level(JID) ->
     case acl:match_rule(global, configure, JID) of
       allow -> global;
@@ -397,6 +405,8 @@ get_permission_level(JID) ->
 	      end
 	end).
 
+-spec get_local_items(mod_disco:items_acc(), jid(), jid(),
+		      binary(), binary()) -> mod_disco:items_acc().
 get_local_items(Acc, From, #jid{lserver = LServer} = To,
 		<<"">>, Lang) ->
     case gen_mod:is_loaded(LServer, mod_adhoc) of
@@ -489,10 +499,8 @@ get_local_items(Acc, From, #jid{lserver = LServer} = To,
     end.
 
 %%%-----------------------------------------------------------------------
-
-%% @spec ({PermissionLevel, Host}, [string()], Server::string(), Lang)
-%%              -> {result, [xmlelement()]}
-%%       PermissionLevel = global | vhost
+-spec get_local_items({global | vhost, binary()}, [binary()],
+		      binary(), binary()) -> {result, [disco_item()]} | {error, stanza_error()}.
 get_local_items(_Host, [], Server, Lang) ->
     {result,
      [?NODE(?T("Configuration"), <<"config">>),
@@ -550,7 +558,7 @@ get_local_items({_, Host},
 				       name = <<U/binary, $@, S/binary>>}
 		   end, Sub)}
     catch _:_ ->
-	    xmpp:err_not_acceptable()
+	    {error, xmpp:err_not_acceptable()}
     end;
 get_local_items({_, Host}, [<<"outgoing s2s">>],
 		_Server, Lang) ->
@@ -638,6 +646,7 @@ get_local_items(_Host,
 get_local_items(_Host, _, _Server, _Lang) ->
     {error, xmpp:err_item_not_found()}.
 
+-spec get_online_vh_users(binary()) -> [disco_item()].
 get_online_vh_users(Host) ->
     case catch ejabberd_sm:get_vh_session_list(Host) of
       {'EXIT', _Reason} -> [];
@@ -650,6 +659,7 @@ get_online_vh_users(Host) ->
 		    end, SURs)
     end.
 
+-spec get_all_vh_users(binary()) -> [disco_item()].
 get_all_vh_users(Host) ->
     case catch ejabberd_auth:get_users(Host)
 	of
@@ -686,6 +696,7 @@ get_all_vh_users(Host) ->
 	  end
     end.
 
+-spec get_outgoing_s2s(binary(), binary()) -> [disco_item()].
 get_outgoing_s2s(Host, Lang) ->
     case catch ejabberd_s2s:dirty_get_connections() of
       {'EXIT', _Reason} -> [];
@@ -703,6 +714,7 @@ get_outgoing_s2s(Host, Lang) ->
 	    end, lists:usort(TConns))
     end.
 
+-spec get_outgoing_s2s(binary(), binary(), binary()) -> [disco_item()].
 get_outgoing_s2s(Host, Lang, To) ->
     case catch ejabberd_s2s:dirty_get_connections() of
       {'EXIT', _Reason} -> [];
@@ -719,6 +731,7 @@ get_outgoing_s2s(Host, Lang, To) ->
 				       Connections)))
     end.
 
+-spec get_running_nodes(binary(), binary()) -> [disco_item()].
 get_running_nodes(Server, _Lang) ->
     case catch mnesia:system_info(running_db_nodes) of
       {'EXIT', _Reason} -> [];
@@ -733,6 +746,7 @@ get_running_nodes(Server, _Lang) ->
 	    lists:sort(DBNodes))
     end.
 
+-spec get_stopped_nodes(binary()) -> [disco_item()].
 get_stopped_nodes(_Lang) ->
     case catch lists:usort(mnesia:system_info(db_nodes) ++
 			     mnesia:system_info(extra_db_nodes))
@@ -785,6 +799,7 @@ adhoc_local_commands(Acc, From,
       _ -> Acc
     end.
 
+-spec adhoc_local_commands(jid(), jid(), adhoc_command()) -> adhoc_command() | {error, stanza_error()}.
 adhoc_local_commands(From,
 		     #jid{lserver = LServer} = _To,
 		     #adhoc_command{lang = Lang, node = Node,
@@ -852,6 +867,9 @@ adhoc_local_commands(From,
 		      #xdata_option{label = tr(Lang, ?T("Remote copy")),
 				    value = <<"unknown">>}]}).
 
+-spec get_form(binary(), [binary()], binary()) -> {result, xdata()} |
+						  {result, completed, xdata()} |
+						  {error, stanza_error()}.
 get_form(_Host, [<<"running nodes">>, ENode, <<"DB">>],
 	 Lang) ->
     case search_running_node(ENode) of
@@ -1169,6 +1187,8 @@ get_form(Host, ?NS_ADMINL(<<"get-online-users-num">>),
 get_form(_Host, _, _Lang) ->
     {error, xmpp:err_service_unavailable()}.
 
+-spec set_form(jid(), binary(), [binary()], binary(), xdata()) -> {result, xdata() | undefined} |
+								  {error, stanza_error()}.
 set_form(_From, _Host,
 	 [<<"running nodes">>, ENode, <<"DB">>], Lang, XData) ->
     case search_running_node(ENode) of
@@ -1543,22 +1563,28 @@ set_form(From, Host, ?NS_ADMINL(<<"user-stats">>), Lang,
 set_form(_From, _Host, _, _Lang, _XData) ->
     {error, xmpp:err_service_unavailable()}.
 
-get_value(Field, XData) -> hd(get_values(Field, XData)).
+-spec get_value(binary(), xdata()) -> binary().
+get_value(Field, XData) ->
+    hd(get_values(Field, XData)).
 
+-spec get_values(binary(), xdata()) -> [binary()].
 get_values(Field, XData) ->
     xmpp_util:get_xdata_values(Field, XData).
 
+-spec search_running_node(binary()) -> false | node().
 search_running_node(SNode) ->
     search_running_node(SNode,
 			mnesia:system_info(running_db_nodes)).
 
+-spec search_running_node(binary(), [node()]) -> false | node().
 search_running_node(_, []) -> false;
 search_running_node(SNode, [Node | Nodes]) ->
-    case iolist_to_binary(atom_to_list(Node)) of
-      SNode -> Node;
-      _ -> search_running_node(SNode, Nodes)
+    case atom_to_binary(Node, utf8) of
+	SNode -> Node;
+	_ -> search_running_node(SNode, Nodes)
     end.
 
+-spec stop_node(jid(), binary(), binary(), restart | stop, xdata()) -> {result, undefined}.
 stop_node(From, Host, ENode, Action, XData) ->
     Delay = binary_to_integer(get_value(<<"delay">>, XData)),
     Subject = case get_value(<<"subject">>, XData) of
@@ -1586,9 +1612,10 @@ stop_node(From, Host, ENode, Action, XData) ->
     end,
     Time = timer:seconds(Delay),
     Node = misc:binary_to_atom(ENode),
-    {ok, _} = timer:apply_after(Time, rpc, call, [Node, init, Action, []]),
+    {ok, _} = timer:apply_after(Time, ejabberd_cluster, call, [Node, init, Action, []]),
     {result, undefined}.
 
+-spec get_last_info(binary(), binary()) -> {ok, non_neg_integer(), binary()} | not_found.
 get_last_info(User, Server) ->
     case gen_mod:is_loaded(Server, mod_last) of
       true -> mod_last:get_last_info(User, Server);
@@ -1596,7 +1623,8 @@ get_last_info(User, Server) ->
     end.
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
--spec adhoc_sm_commands(adhoc_command(), jid(), jid(), adhoc_command()) -> adhoc_command().
+-spec adhoc_sm_commands(adhoc_command(), jid(), jid(), adhoc_command()) -> adhoc_command() |
+									   {error, stanza_error()}.
 adhoc_sm_commands(_Acc, From,
 		  #jid{user = User, server = Server, lserver = LServer},
 		  #adhoc_command{lang = Lang, node = <<"config">>,
@@ -1627,6 +1655,8 @@ adhoc_sm_commands(_Acc, From,
     end;
 adhoc_sm_commands(Acc, _From, _To, _Request) -> Acc.
 
+-spec get_sm_form(binary(), binary(), binary(), binary()) -> {result, xdata()} |
+							     {error, stanza_error()}.
 get_sm_form(User, Server, <<"config">>, Lang) ->
     {result,
      #xdata{type = form,
@@ -1650,6 +1680,8 @@ get_sm_form(User, Server, <<"config">>, Lang) ->
 get_sm_form(_User, _Server, _Node, _Lang) ->
     {error, xmpp:err_service_unavailable()}.
 
+-spec set_sm_form(binary(), binary(), binary(), adhoc_command()) -> adhoc_command() |
+								    {error, stanza_error()}.
 set_sm_form(User, Server, <<"config">>,
 	    #adhoc_command{lang = Lang, node = Node,
 			   sid = SessionID, xdata = XData}) ->
diff --git a/src/mod_delegation.erl b/src/mod_delegation.erl
index c49f973a..8dbc903e 100644
--- a/src/mod_delegation.erl
+++ b/src/mod_delegation.erl
@@ -44,7 +44,6 @@
 -include("xmpp.hrl").
 -include("translate.hrl").
 
--type disco_acc() :: {error, stanza_error()} | {result, [binary()]} | empty.
 -type route_type() :: ejabberd_sm | ejabberd_local.
 -type delegations() :: #{{binary(), route_type()} => {binary(), disco_info()}}.
 -record(state, {server_host = <<"">> :: binary()}).
@@ -115,19 +114,21 @@ ejabberd_local(IQ) ->
 ejabberd_sm(IQ) ->
     process_iq(IQ, ejabberd_sm).
 
--spec disco_local_features(disco_acc(), jid(), jid(), binary(), binary()) -> disco_acc().
+-spec disco_local_features(mod_disco:features_acc(), jid(), jid(),
+			   binary(), binary()) -> mod_disco:features_acc().
 disco_local_features(Acc, From, To, Node, Lang) ->
     disco_features(Acc, From, To, Node, Lang, ejabberd_local).
 
--spec disco_sm_features(disco_acc(), jid(), jid(), binary(), binary()) -> disco_acc().
+-spec disco_sm_features(mod_disco:features_acc(), jid(), jid(),
+			binary(), binary()) -> mod_disco:features_acc().
 disco_sm_features(Acc, From, To, Node, Lang) ->
     disco_features(Acc, From, To, Node, Lang, ejabberd_sm).
 
--spec disco_local_identity(disco_acc(), jid(), jid(), binary(), binary()) -> disco_acc().
+-spec disco_local_identity([identity()], jid(), jid(), binary(), binary()) -> [identity()].
 disco_local_identity(Acc, From, To, Node, Lang) ->
     disco_identity(Acc, From, To, Node, Lang, ejabberd_local).
 
--spec disco_sm_identity(disco_acc(), jid(), jid(), binary(), binary()) -> disco_acc().
+-spec disco_sm_identity([identity()], jid(), jid(), binary(), binary()) -> [identity()].
 disco_sm_identity(Acc, From, To, Node, Lang) ->
     disco_identity(Acc, From, To, Node, Lang, ejabberd_sm).
 
@@ -335,8 +336,8 @@ send_disco_queries(LServer, Host, NS) ->
       end, [{ejabberd_local, <<(?NS_DELEGATION)/binary, "::", NS/binary>>},
 	    {ejabberd_sm, <<(?NS_DELEGATION)/binary, ":bare:", NS/binary>>}]).
 
--spec disco_features(disco_acc(), jid(), jid(), binary(), binary(),
-		     route_type()) -> disco_acc().
+-spec disco_features(mod_disco:features_acc(), jid(), jid(), binary(), binary(),
+		     route_type()) -> mod_disco:features_acc().
 disco_features(Acc, _From, To, <<"">>, _Lang, Type) ->
     Delegations = get_delegations(To#jid.lserver),
     Features = my_features(Type) ++
@@ -354,8 +355,8 @@ disco_features(Acc, _From, To, <<"">>, _Lang, Type) ->
 disco_features(Acc, _, _, _, _, _) ->
     Acc.
 
--spec disco_identity(disco_acc(), jid(), jid(), binary(), binary(),
-		     route_type()) -> disco_acc().
+-spec disco_identity([identity()], jid(), jid(), binary(), binary(),
+		     route_type()) -> [identity()].
 disco_identity(Acc, _From, To, <<"">>, _Lang, Type) ->
     Delegations = get_delegations(To#jid.lserver),
     Identities = lists:flatmap(
@@ -364,11 +365,7 @@ disco_identity(Acc, _From, To, <<"">>, _Lang, Type) ->
 		      (_) ->
 			   []
 		   end, maps:to_list(Delegations)),
-    case Acc of
-	empty when Identities /= [] -> {result, Identities};
-	{result, Ids} -> {result, Ids ++ Identities};
-	Acc -> Acc
-    end;
+    Acc ++ Identities;
 disco_identity(Acc, _From, _To, _Node, _Lang, _Type) ->
     Acc.
 
diff --git a/src/mod_fail2ban.erl b/src/mod_fail2ban.erl
index eeb9186a..77039391 100644
--- a/src/mod_fail2ban.erl
+++ b/src/mod_fail2ban.erl
@@ -225,13 +225,16 @@ log_and_disconnect(#{ip := {Addr, _}, lang := Lang} = State, Attempts, UnbanTS)
     Err = xmpp:serr_policy_violation({Format, Args}, Lang),
     {stop, ejabberd_c2s:send(State, Err)}.
 
+-spec is_whitelisted(binary(), inet:ip_address()) -> boolean().
 is_whitelisted(Host, Addr) ->
     Access = mod_fail2ban_opt:access(Host),
     acl:match_rule(Host, Access, Addr) == allow.
 
+-spec seconds_to_now(non_neg_integer()) -> erlang:timestamp().
 seconds_to_now(Secs) ->
     {Secs div 1000000, Secs rem 1000000, 0}.
 
+-spec format_date(calendar:datetime()) -> iolist().
 format_date({{Year, Month, Day}, {Hour, Minute, Second}}) ->
     io_lib:format("~2..0w:~2..0w:~2..0w ~2..0w.~2..0w.~4..0w",
 		  [Hour, Minute, Second, Day, Month, Year]).
diff --git a/src/mod_last.erl b/src/mod_last.erl
index ec08a644..28b66be0 100644
--- a/src/mod_last.erl
+++ b/src/mod_last.erl
@@ -45,6 +45,8 @@
 
 -define(LAST_CACHE, last_activity_cache).
 
+-type c2s_state() :: ejabberd_c2s:state().
+
 -callback init(binary(), gen_mod:opts()) -> any().
 -callback import(binary(), #last_activity{}) -> ok | pass.
 -callback get_last(binary(), binary()) ->
@@ -144,6 +146,7 @@ process_sm_iq(#iq{from = From, to = To, lang = Lang} = IQ) ->
 	    xmpp:make_error(IQ, xmpp:err_subscription_required(Txt, Lang))
     end.
 
+-spec privacy_check_packet(allow | deny, c2s_state(), stanza(), in | out) -> allow | deny | {stop, deny}.
 privacy_check_packet(allow, C2SState,
 		     #iq{from = From, to = To, type = T} = IQ, in)
   when T == get; T == set ->
diff --git a/src/mod_time.erl b/src/mod_time.erl
index 1355ba46..53f2e543 100644
--- a/src/mod_time.erl
+++ b/src/mod_time.erl
@@ -50,6 +50,7 @@ stop(Host) ->
 reload(_Host, _NewOpts, _OldOpts) ->
     ok.
 
+-spec process_local_iq(iq()) -> iq().
 process_local_iq(#iq{type = set, lang = Lang} = IQ) ->
     Txt = ?T("Value 'set' of 'type' attribute is not allowed"),
     xmpp:make_error(IQ, xmpp:err_not_allowed(Txt, Lang));
diff --git a/src/mod_vcard.erl b/src/mod_vcard.erl
index b7be42a1..41f04940 100644
--- a/src/mod_vcard.erl
+++ b/src/mod_vcard.erl
@@ -132,7 +132,8 @@ init([Host, Opts]) ->
     end,
     {ok, #state{hosts = MyHosts, server_host = Host}}.
 
-handle_call(_Call, _From, State) ->
+handle_call(Call, From, State) ->
+    ?WARNING_MSG("Unexpected call from ~p: ~p", [From, Call]),
     {noreply, State}.
 
 handle_cast(Cast, State) ->
@@ -443,6 +444,7 @@ mk_search_form(JID, ServerHost, Lang) ->
 		  Lang, ?T("You need an x:data capable client to search")),
 	    xdata = X}.
 
+-spec make_instructions(module(), binary()) -> binary().
 make_instructions(Mod, Lang) ->
     Fill = translate:translate(
 	     Lang,