Added specs for gm callbacks.

src/gen_server2.erl

@@ -252,7 +252,7 @@
     {stop, Reason :: term(), NewState :: term()}.
 -callback terminate(Reason :: (normal | shutdown | {shutdown, term()} | term()),
                     State :: term()) ->
-    (ok | term()).
+    ok | term().
 -callback code_change(OldVsn :: (term() | {down, term()}), State :: term(),
                       Extra :: term()) ->
     {ok, NewState :: term()} | {error, Reason :: term()}.

src/gm.erl

@@ -57,8 +57,8 @@
 %% you wish to be passed into the callback module's functions. The
 %% joined/2 function will be called when we have joined the group,
 %% with the arguments passed to start_link and a list of the current
-%% members of the group. See the comments in behaviour_info/1 below
-%% for further details of the callback functions.
+%% members of the group. See the callbacks specs and the comments
+%% below for further details of the callback functions.
 %%
 %% leave/1
 %% Provide the Pid. Removes the Pid from the group. The callback
@@ -378,7 +378,9 @@
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2,
          code_change/3, prioritise_info/2]).
 
+-ifndef(use_specs).
 -export([behaviour_info/1]).
+-endif.
 
 -export([table_definitions/0]).
 
@@ -431,10 +433,6 @@
 -spec(confirmed_broadcast/2 :: (pid(), any()) -> 'ok').
 -spec(group_members/1 :: (pid()) -> [pid()]).
 
--endif.
-
-behaviour_info(callbacks) ->
-    [
 %% The joined, members_changed and handle_msg callbacks can all
 %% return any of the following terms:
 %%
@@ -451,7 +449,8 @@ behaviour_info(callbacks) ->
 
 %% Called when we've successfully joined the group. Supplied with
 %% Args provided in start_link, plus current group members.
-     {joined, 2},
+-callback joined(Args :: term(), Members :: [pid()]) ->
+    ok | {stop, Reason :: term()} | {become, Module :: atom(), Args :: any()}.
 
 %% Supplied with Args provided in start_link, the list of new
 %% members and the list of members previously known to us that
@@ -463,7 +462,9 @@ behaviour_info(callbacks) ->
 %% any messages from it; and (2) we will not see members die that
 %% we have not seen born (or supplied in the members to
 %% joined/2).
-     {members_changed, 3},
+-callback members_changed(Args :: term(), Births :: [pid()],
+                          Deaths :: [pid()]) ->
+    ok | {stop, Reason :: term()} | {become, Module :: atom(), Args :: any()}.
 
 %% Supplied with Args provided in start_link, the sender, and the
 %% message. This does get called for messages injected by this
@@ -471,16 +472,24 @@ behaviour_info(callbacks) ->
 %% significance of this invocation: it does not indicate that the
 %% message has made it to any other members, let alone all other
 %% members.
-     {handle_msg, 3},
+-callback handle_msg(Args :: term(), From :: pid(), Message :: term()) ->
+    ok | {stop, Reason :: term()} | {become, Module :: atom(), Args :: any()}.
 
 %% Called on gm member termination as per rules in gen_server,
 %% with the Args provided in start_link plus the termination
 %% Reason.
-     {terminate, 2}
-    ];
+-callback terminate(Args :: term(), Reason :: term()) ->
+    ok | term().
+
+-else.
+
+behaviour_info(callbacks) ->
+    [{joined, 2}, {members_changed, 3}, {handle_msg, 3}, {terminate, 2}];
 behaviour_info(_Other) ->
     undefined.
 
+-endif.
+
 create_tables() ->
     create_tables([?TABLE]).