Merge pull request #130 from stritzinger/otp-21-stacktrace-compatibility

Add compatibility for OTP 21+ stack traces

Author: ThomasArts

src/riak_ensemble_exchange.erl

@@ -22,12 +22,14 @@
 -compile(nowarn_export_all).
 -compile(export_all).
 
+-include("stacktrace.hrl").
+
 start_exchange(Ensemble, Peer, Id, Tree, Peers, Views, Trusted) ->
     spawn(fun() ->
                   try
                       perform_exchange(Ensemble, Peer, Id, Tree, Peers, Views, Trusted)
-                  catch Class:Reason ->
-                          io:format("CAUGHT: ~p/~p~n~p~n", [Class, Reason, erlang:get_stacktrace()]),
+                  catch ?_exception_(Class, Reason, StackToken) ->
+                          io:format("CAUGHT: ~p/~p~n~p~n", [Class, Reason, ?_get_stacktrace_(StackToken)]),
                           gen_fsm_compat:send_event(Peer, exchange_failed)
                   end
           end).

src/stacktrace.hrl

@@ -0,0 +1,33 @@
+%% Originating from Quviq AB
+%% Fix to make Erlang programs compile on both OTP20 and OTP21.
+%%
+%% Get the stack trace in a way that is backwards compatible. Luckily
+%% OTP_RELEASE was introduced in the same version as the new preferred way of
+%% getting the stack trace. A _catch_/2 macro is provided for consistency in
+%% cases where the stack trace is not needed.
+%%
+%% Example use:
+%%    try f(...)
+%%    catch
+%%         ?_exception_(_, Reason, StackToken) ->
+%%             case Reason of
+%%                 {fail, Error} -> ok;
+%%                 _             -> {'EXIT', Reason, ?_get_stacktrace_(StackToken)}
+%%             end
+%%     end,
+
+-ifdef(OTP_RELEASE). %% This implies 21 or higher
+-define(_exception_(Class, Reason, StackToken), Class:Reason:StackToken).
+-define(_get_stacktrace_(StackToken), StackToken).
+-define(_current_stacktrace_(),
+        try
+            exit('$get_stacktrace')
+        catch
+            exit:'$get_stacktrace':__GetCurrentStackTrace ->
+                __GetCurrentStackTrace
+        end).
+-else.
+-define(_exception_(Class, Reason, _), Class:Reason).
+-define(_get_stacktrace_(_), erlang:get_stacktrace()).
+-define(_current_stacktrace_(), erlang:get_stacktrace()).
+-endif.