Merge bug26000 into stable again

2 files changed, 27 insertions, 7 deletions

diff --git a/src/mirrored_supervisor.erl b/src/mirrored_supervisor.erl
index 6c5c09df..f44b1f1d 100644
--- a/src/mirrored_supervisor.erl
+++ b/src/mirrored_supervisor.erl
@@ -70,6 +70,19 @@
 %%    application should invoke create_tables() (or table_definitions()
 %%    if it wants to manage table creation itself).
 %%
+%% The TxFun parameter to start_link/{4,5} is a function which the
+%% mirrored supervisor can use to execute Mnesia transactions. In the
+%% RabbitMQ server this goes via a worker pool; in other cases a
+%% function like:
+%%
+%%  tx_fun(Fun) ->
+%%      case mnesia:sync_transaction(Fun) of
+%%          {atomic,  Result}         -> Result;
+%%          {aborted, Reason}         -> throw({error, Reason})
+%%      end.
+%%
+%% could be used.
+%%
 %% Internals
 %% ---------
 %%
@@ -161,7 +174,7 @@
 
 -type group_name() :: any().
 
--type(tx_fun() :: fun((fun(() -> any())) -> any())).
+-type(tx_fun() :: fun((fun(() -> A)) -> A)).
 
 -spec start_link(GroupName, TxFun, Module, Args) -> startlink_ret() when
       GroupName :: group_name(),
diff --git a/src/mirrored_supervisor_tests.erl b/src/mirrored_supervisor_tests.erl
index 780ef11d..6d7c55dd 100644
--- a/src/mirrored_supervisor_tests.erl
+++ b/src/mirrored_supervisor_tests.erl
@@ -175,14 +175,14 @@ test_start_idempotence() ->
 
 test_unsupported() ->
     try
-        ?MS:start_link({global, foo}, get_group(group), ?MODULE,
+        ?MS:start_link({global, foo}, get_group(group), fun tx_fun/1, ?MODULE,
                        {sup, one_for_one, []}),
         exit(no_global)
     catch error:badarg ->
             ok
     end,
     try
-        ?MS:start_link({local, foo}, get_group(group), ?MODULE,
+        ?MS:start_link({local, foo}, get_group(group), fun tx_fun/1, ?MODULE,
                        {sup, simple_one_for_one, []}),
         exit(no_sofo)
     catch error:badarg ->
@@ -192,7 +192,7 @@ test_unsupported() ->
 
 %% Just test we don't blow up
 test_ignore() ->
-    ?MS:start_link({local, foo}, get_group(group), ?MODULE,
+    ?MS:start_link({local, foo}, get_group(group), fun tx_fun/1, ?MODULE,
                    {sup, fake_strategy_for_ignore, []}),
     passed.
 
@@ -202,7 +202,7 @@ test_startup_failure() ->
 
 test_startup_failure(Fail) ->
     process_flag(trap_exit, true),
-    ?MS:start_link(get_group(group), ?MODULE,
+    ?MS:start_link(get_group(group), fun tx_fun/1, ?MODULE,
                    {sup, one_for_one, [childspec(Fail)]}),
     receive
         {'EXIT', _, shutdown} ->
@@ -236,10 +236,11 @@ start_sup(Name, Group) ->
     start_sup({Name, []}, Group).
 
 start_sup0(anon, Group, ChildSpecs) ->
-    ?MS:start_link(Group, ?MODULE, {sup, one_for_one, ChildSpecs});
+    ?MS:start_link(Group, fun tx_fun/1, ?MODULE,
+                   {sup, one_for_one, ChildSpecs});
 
 start_sup0(Name, Group, ChildSpecs) ->
-    ?MS:start_link({local, Name}, Group, ?MODULE,
+    ?MS:start_link({local, Name}, Group, fun tx_fun/1, ?MODULE,
                    {sup, one_for_one, ChildSpecs}).
 
 childspec(Id) ->
@@ -258,6 +259,12 @@ pid_of(Id) ->
     {received, Pid, ping} = call(Id, ping),
     Pid.
 
+tx_fun(Fun) ->
+    case mnesia:sync_transaction(Fun) of
+        {atomic,  Result}         -> Result;
+        {aborted, Reason}         -> throw({error, Reason})
+    end.
+
 inc_group() ->
     Count = case get(counter) of
                 undefined -> 0;