Handle upgrade from pre R15 to post R15 sasl

New emulator upgrade mechanism introduced in R15 can only work if the
sasl version to upgrade from is 2.2 or later. I.e. if we are already
running at least R15.

This commit adds backwards compatiblity for upgrades from earlier
versions, meaning that the new code is loaded into the old emulator
and code_change is executed - then after all application code is
updated, the emulator is restarted with the new erts version.

Note that this might cause problems if the new code is compiled with
the new emulator and there have been updates to the beam format. If
this happens, the workaround is to compile the new code with the old
emulator.

1 files changed, 30 insertions, 10 deletions

diff --git a/lib/sasl/src/systools_relup.erl b/lib/sasl/src/systools_relup.erl
index 27960e9938..5346538dc8 100644
--- a/lib/sasl/src/systools_relup.erl
+++ b/lib/sasl/src/systools_relup.erl
@@ -112,6 +112,7 @@
 -export([mk_relup/3, mk_relup/4, format_error/1, format_warning/1]).
 -include("systools.hrl").
 
+-define(R15_SASL_VSN,"2.2").
 
 %% For test purposes only - used by kernel, stdlib and sasl tests
 -export([appup_search_for_version/2]).
@@ -269,20 +270,25 @@ foreach_baserel_up(TopRel, TopApps, [BaseRelDc|BaseRelDcs], Path, Opts,
 
     {RUs4, Ws4} = check_for_emulator_restart(TopRel, BaseRel, RUs3, Ws3, Opts),
 
-    BaseApps =
+    {BaseNameVsns,BaseApps} =
 	case systools_make:get_release(BaseRelFile, Path) of
 	    {ok, _, NameVsnApps, _Warns} ->
-		lists:map(fun({_,App}) -> App end, NameVsnApps);
+		%% NameVsnApps = [{{Name,Vsn},#application}]
+		%% Gives two lists - [{Name,Vsn}] and [#application]
+		lists:unzip(NameVsnApps);
 	    Other1 ->
 		throw(Other1)
 	end,
 
     case systools_rc:translate_scripts(up, RUs4, TopApps, BaseApps) of
-	{ok, RUs} ->
+	{ok, RUs5} ->
+
+	    {RUs, Ws5} = fix_r15_sasl_upgrade(RUs5,Ws4,BaseNameVsns),
+
 	    VDR = {BaseRel#release.vsn,
 		   extract_description(BaseRelDc), RUs},
 	    foreach_baserel_up(TopRel, TopApps, BaseRelDcs, Path, 
-			       Opts, Ws4, [VDR| Acc]);
+			       Opts, Ws5, [VDR| Acc]);
 	XXX ->
 	    throw(XXX)
     end;
@@ -346,12 +352,9 @@ foreach_baserel_dn( _, _, [], _, _, Ws, Acc) ->
 check_for_emulator_restart(#release{erts_vsn = Vsn1, name = N1}, 
                            #release{erts_vsn = Vsn2, name = N2}, RUs, Ws, 
                            Opts) when Vsn1 /= Vsn2 ->
-    %% The diff_vsn_restart_new_emulator instruction will be replaced
-    %% by a restart_new_emulator instruction in systools_rc, and
-    %% placed in the proper order according to mode (up or dn).
-    %% We will also allow an extra restart of emulator (specified by
-    %% the restart_emulator option) at the end of the upgrade, for
-    %% application specific purposes.
+    %% Automatically insert a restart_new_emulator instruction when
+    %% erts version is changed. Also allow extra restart at the end of
+    %% the upgrade if restart_emulator option is given.
     NewRUs = [[restart_new_emulator]|RUs],
     NewWs = [{erts_vsn_changed, {N1, N2}} | Ws],
     check_for_restart_emulator_opt(NewRUs, NewWs, Opts);
@@ -365,6 +368,23 @@ check_for_restart_emulator_opt(RUs, Ws, Opts) ->
     end.
 
 
+%% Special handling of the upgrade from pre R15 to post R15. In R15,
+%% upgrade of the emulator was improved by moving the restart of the
+%% emulator before the rest of the upgrade instructions. However, it
+%% can only work if the release_handler is already upgraded to a post
+%% R15 version. If not, the upgrade instructions must be backwards
+%% compatible - i.e. restart_new_emulator will be the last
+%% instruction, executed after all code loading, code_change etc.
+fix_r15_sasl_upgrade([restart_new_emulator | RestRUs]=RUs, Ws, BaseApps) ->
+    case lists:keyfind(sasl,1,BaseApps) of
+	{sasl,Vsn} when Vsn < ?R15_SASL_VSN -> 
+	    {lists:delete(restart_emulator,RestRUs) ++ [restart_new_emulator],
+	     [pre_R15_emulator_upgrade|Ws]};
+	_ ->
+	    {RUs,Ws}
+    end;
+fix_r15_sasl_upgrade(RUs, Ws, _BaseApps) ->
+    {RUs,Ws}.
 
 
 %% collect_appup_scripts(Mode, TopApps, BaseRel, Ws, RUs) -> {NRUs, NWs}