Merge pull request #169 from flambard/master

Only shrink the pool when auto_size is true

src/gproc_pool.erl

@@ -827,29 +827,29 @@ remove_worker_(Pool, Name) ->
 
 do_remove_worker_(Pool, Name) ->
     K = ?POOL(Pool),
+    AutoSize = gproc:get_attribute(K, shared, auto_size),
     Ws0 = get_workers_(K),
-    Ws1 = del_slot(Name, Ws0),
+    Ws1 = del_slot(Name, Ws0, AutoSize),
     gproc:unreg_shared(?POOL_WRK(Pool, Name)),
-    case (NewLen = length(Ws1)) - length(Ws0) of
-        0 -> ok;
-        Diff when Diff < 0 ->
-            case gproc:get_attribute(K, shared, auto_size) of
-                true ->
+    case AutoSize of
+        false -> ok;
+        true ->
+            case (NewLen = length(Ws1)) - length(Ws0) of
+                0 -> ok;
+                Diff when Diff < 0 ->
                     {_, Type} = gproc:get_value(K, shared),
-                    gproc:set_value_shared(K, {NewLen, Type});
-                false ->
-                    ok
+                    gproc:set_value_shared(K, {NewLen, Type})
             end
     end,
     gproc:set_attributes_shared(K, [{workers, Ws1}]),
     ok.
 
-del_slot(Name, [{Name,_}]) ->
+del_slot(Name, [{Name,_}], true) ->
     [];
-del_slot(Name, [{Name, Pos}|T]) ->
+del_slot(Name, [{Name, Pos}|T], _AutoSize) ->
     [Pos|T];
-del_slot(Name, [H|T]) ->
-    [H|del_slot(Name, T)].
+del_slot(Name, [H|T], AutoSize) ->
+    [H|del_slot(Name, T, AutoSize)].
 
 find_slot(Name, _, [], Sz, _, Auto) ->
     case {Sz, Auto} of

test/gproc_tests.erl

@@ -162,7 +162,9 @@ reg_test_() ->
       , ?_test(t_is_clean())
       , {spawn, ?_test(?debugVal(t_simple_pool()))}
       , ?_test(t_is_clean())
-      , {spawn, ?_test(?debugVal(t_pool_add_worker_race()))}
+      , {spawn, ?_test(?debugVal(t_pool_add_worker_size_1_no_auto_size()))}
+      , ?_test(t_is_clean())
+      , {spawn, ?_test(?debugVal(t_pool_add_worker_size_2_no_auto_size()))}
       , ?_test(t_is_clean())
      ]}.
 
@@ -1007,26 +1009,27 @@ t_simple_pool()->
 
 %% verifying #167 - Removing a worker from a pool does not make room
 %% for a new worker (size was erroneously adjusted down, though auto_size = false)
-t_pool_add_worker_race() ->
+t_pool_add_worker_size_1_no_auto_size() ->
     ok = gproc_pool:new(p2, direct, [{size, 1}, {auto_size, false}]),
     [] = gproc_pool:defined_workers(p2),
     Pos1 = gproc_pool:add_worker(p2, worker1),
     [{worker1, Pos1, 0}] = gproc_pool:defined_workers(p2),
     io:fwrite("G = ~p~n", [ets:tab2list(gproc)]),
-    Pid = spawn(fun() ->
-                        true = gproc_pool:connect_worker(p2, worker1),
-                        receive after 100 -> bye end
-                end),
-    Monitor = monitor(process, Pid),
-    receive
-        {'DOWN', Monitor, process, _, _} -> ok
-    end,
     true = gproc_pool:remove_worker(p2, worker1),
     [] = gproc_pool:defined_workers(p2), %% the pool seems to be empty
     Pos2 = gproc_pool:add_worker(p2, worker2), %% throws error:pool_full
     true = is_integer(Pos2),
     true = gproc_pool:force_delete(p2).
 
+t_pool_add_worker_size_2_no_auto_size() ->
+    gproc_pool:new(p3, direct, [{size, 2}, {auto_size, false}]),
+    gproc_pool:add_worker(p3, worker1),
+    gproc_pool:add_worker(p3, worker2),
+    gproc_pool:remove_worker(p3, worker2),
+    gproc_pool:add_worker(p3, worker3),
+    gproc_pool:force_delete(p3).
+
+
 
 
 get_msg() ->