Merge branch 'maint'

3 files changed, 168 insertions, 9 deletions

diff --git a/lib/kernel/doc/src/application.xml b/lib/kernel/doc/src/application.xml
index da16964d61..29eaf348a9 100644
--- a/lib/kernel/doc/src/application.xml
+++ b/lib/kernel/doc/src/application.xml
@@ -253,15 +253,30 @@ Nodes = [cp1@cave, {cp2@cave, cp3@cave}]</code>
         </warning>
       </desc>
     </func>
-	<func>
+    <func>
       <name name="ensure_started" arity="1"/>
       <name name="ensure_started" arity="2"/>
       <fsummary>Load and start an application</fsummary>
-	  <desc>
-		  <p>Equivalent to <seealso marker="#start/2"><c>application:start/1,2</c></seealso> except
-			  it returns <c>ok</c> for already started applications.</p>
-	  </desc>
-	</func>
+      <desc>
+	<p>Equivalent to <seealso marker="#start/2"><c>application:start/1,2</c></seealso> except
+	it returns <c>ok</c> for already started applications.</p>
+      </desc>
+    </func>
+    <func>
+        <name name="ensure_all_started" arity="1"/>
+        <name name="ensure_all_started" arity="2"/>
+        <fsummary>Load and start an application and its dependencies, recursively</fsummary>
+        <desc>
+            <p>Equivalent to calling <seealso marker="#start/2"><c>application:start/1,2</c></seealso>
+               repeatedly on all dependencies that have not yet been started for an application.
+               The function returns <c>{ok, AppNames}</c> for a successful start or for an already started
+               application (which are however omitted from the <c>AppNames</c> list), and reports
+               <c>{error, {AppName,Reason}}</c> for errors, where <c>Reason</c> is any possible reason
+               returned by <seealso marker="#start/2"><c>application:start/1,2</c></seealso> when starting a
+               specific dependency. In case of an error, the applications that were started by the
+               function are stopped to bring the set of running applications back to its initial state.</p>
+        </desc>
+    </func>
     <func>
       <name name="start" arity="1"/>
       <name name="start" arity="2"/>
diff --git a/lib/kernel/src/application.erl b/lib/kernel/src/application.erl
index 5dd6b73857..4e8ba1b78a 100644
--- a/lib/kernel/src/application.erl
+++ b/lib/kernel/src/application.erl
@@ -18,7 +18,8 @@
 %%
 -module(application).
 
--export([start/1, start/2, start_boot/1, start_boot/2, stop/1, 
+-export([ensure_all_started/1, ensure_all_started/2, start/1, start/2,
+	 start_boot/1, start_boot/2, stop/1, 
 	 load/1, load/2, unload/1, takeover/2,
 	 which_applications/0, which_applications/1,
 	 loaded_applications/0, permit/2]).
@@ -113,6 +114,46 @@ load1(Application, DistNodes) ->
 unload(Application) ->
     application_controller:unload_application(Application).
 
+
+-spec ensure_all_started(Application) -> {'ok', Started} | {'error', Reason} when
+      Application :: atom(),
+      Started :: [atom()],
+      Reason :: term().
+ensure_all_started(Application) ->
+    ensure_all_started(Application, temporary).
+
+-spec ensure_all_started(Application, Type) -> {'ok', Started} | {'error', Reason} when
+      Application :: atom(),
+      Type :: restart_type(),
+      Started :: [atom()],
+      Reason :: term().
+ensure_all_started(Application, Type) ->
+    case ensure_all_started(Application, Type, []) of
+	{ok, Started} ->
+	    {ok, lists:reverse(Started)};
+	{error, Reason, Started} ->
+	    [stop(App) || App <- Started],
+	    {error, Reason}
+    end.
+
+ensure_all_started(Application, Type, Started) ->
+    case start(Application, Type) of
+	ok ->
+	    {ok, [Application | Started]};
+	{error, {already_started, Application}} ->
+	    {ok, Started};
+	{error, {not_started, Dependency}} ->
+	    case ensure_all_started(Dependency, Type, Started) of
+		{ok, NewStarted} ->
+		    ensure_all_started(Application, Type, NewStarted);
+		Error ->
+		    Error
+	    end;
+	{error, Reason} ->
+	    {error, {Application, Reason}, Started}
+    end.
+
+
 -spec start(Application) -> 'ok' | {'error', Reason} when
       Application :: atom(),
       Reason :: term().
diff --git a/lib/kernel/test/application_SUITE.erl b/lib/kernel/test/application_SUITE.erl
index 1ff291be54..9ec8a15861 100644
--- a/lib/kernel/test/application_SUITE.erl
+++ b/lib/kernel/test/application_SUITE.erl
@@ -35,7 +35,7 @@
 
 -export([config_change/1,
 	 distr_changed_tc1/1, distr_changed_tc2/1,
-	 ensure_started/1,
+	 ensure_started/1, ensure_all_started/1,
 	 shutdown_func/1, do_shutdown/1, shutdown_timeout/1]).
 
 -define(TESTCASE, testcase_name).
@@ -52,7 +52,7 @@ all() ->
     [failover, failover_comp, permissions, load,
      load_use_cache, ensure_started, {group, reported_bugs}, start_phases,
      script_start, nodedown_start, permit_false_start_local,
-     permit_false_start_dist, get_key, get_env,
+     permit_false_start_dist, get_key, get_env, ensure_all_started,
      {group, distr_changed}, config_change, shutdown_func, shutdown_timeout].
 
 groups() -> 
@@ -978,6 +978,85 @@ ensure_started(Conf) ->
     ok = application:unload(app1),
     ok.
 
+ensure_all_started(suite) -> [];
+ensure_all_started(doc) -> ["Test application:ensure_all_started/1-2."];
+ensure_all_started(Conf) ->
+
+    {ok, Fd1} = file:open("app1.app", [write]),
+    w_app1(Fd1),
+    file:close(Fd1),
+    {ok, Fd9} = file:open("app9.app", [write]),
+    w_app9(Fd9),
+    file:close(Fd9),
+    {ok, Fd10} = file:open("app10.app", [write]),
+    w_app10_dep9(Fd10),
+    file:close(Fd10),
+    {ok, FdErr} = file:open("app_chain_error.app", [write]),
+    w_app(FdErr, app_chain_error()),
+    file:close(FdErr),
+    {ok, FdErr2} = file:open("app_chain_error2.app", [write]),
+    w_app(FdErr2, app_chain_error2()),
+    file:close(FdErr2),
+
+    %% Single app start/stop
+    false = lists:keyfind(app1, 1, application:which_applications()),
+    {ok, [app1]} = application:ensure_all_started(app1), % app1 started
+    {app1, _, _} = lists:keyfind(app1, 1, application:which_applications()),
+    {ok, []} = application:ensure_all_started(app1), % no start needed
+    ok = application:stop(app1),
+    false = lists:keyfind(app1, 1, application:which_applications()),
+    ok = application:unload(app1),
+
+    %% App or dependency not found.
+    Name = hopefully_not_an_existing_app_file,
+    {error,{Name, {"no such file or directory", _ }}} =
+	application:ensure_all_started(Name),
+
+    %% Start dependencies.
+    {error, {not_started, app9}} = application:start(app10),
+    {ok, [app9,app10]} = application:ensure_all_started(app10, temporary),
+    {app9, _, _} = lists:keyfind(app9, 1, application:which_applications()),
+    {app10, _, _} = lists:keyfind(app10, 1, application:which_applications()),
+    %% Only report apps/dependencies that actually needed to start
+    ok = application:stop(app10),
+    ok = application:unload(app10),
+    {ok, [app10]} = application:ensure_all_started(app10, temporary),
+    ok = application:stop(app9),
+    ok = application:unload(app9),
+    ok = application:stop(app10),
+    ok = application:unload(app10),
+
+    %% Deeper failure chain. We have the following dependencies:
+    %% app_chain_error -> app_chain_error2
+    %% app_chain_error2 -> app10
+    %% app_chain_error2 -> hopefully_not_an_existing_app
+    %% app10 -> app 9
+    %% First we have none running and we expect to have neither app9
+    %% nor app10 running after failing to start
+    %% hopefully_not_an_existing_app
+    {error, {hopefully_not_an_existing_app, {"no such file or directory", _}}}=
+	application:ensure_all_started(app_chain_error),
+    false = lists:keyfind(app9, 1, application:which_applications()),
+    false = lists:keyfind(app10, 1, application:which_applications()),
+    false = lists:keyfind(app_chain_error2,1,application:which_applications()),
+    false = lists:keyfind(app_chain_error, 1, application:which_applications()),
+    %% Here we will have app9 already running, and app10 should be
+    %% able to boot fine.
+    %% In this dependency failing, we expect app9 to still be running, but
+    %% not app10 after failing to start hopefully_not_an_existing_app
+    {ok, [app9]} = application:ensure_all_started(app9, temporary),
+    {error, {hopefully_not_an_existing_app, {"no such file or directory", _}}}=
+	application:ensure_all_started(app_chain_error),
+    {app9, _, _} = lists:keyfind(app9, 1, application:which_applications()),
+    false = lists:keyfind(app10, 1, application:which_applications()),
+    false = lists:keyfind(app_chain_error2,1,application:which_applications()),
+    false = lists:keyfind(app_chain_error, 1, application:which_applications()),
+    ok = application:stop(app9),
+    ok = application:unload(app9),
+    ok = application:unload(app10),
+    ok = application:unload(app_chain_error2),
+    ok = application:unload(app_chain_error),
+    ok.
 
 %%%-----------------------------------------------------------------
 %%% Testing of reported bugs and other tickets.
@@ -2125,6 +2204,24 @@ app_start_error() ->
       {applications, [kernel]},
       {mod, {app_start_error, []}}]}.
 
+app_chain_error() ->
+    {application, app_chain_error,
+     [{description, "ERTS  CXC 138 ce"},
+      {vsn, "2.0"},
+      {modules, []},
+      {registered, []},
+      {applications, [kernel, app_chain_error2]},
+      {mod, {ch_sup, {app_chain_error, 20,20}}}]}.
+
+app_chain_error2() ->
+    {application, app_chain_error2,
+     [{description, "ERTS  CXC 138 ce2"},
+      {vsn, "2.0"},
+      {modules, []},
+      {registered, []},
+      {applications, [kernel, app10, hopefully_not_an_existing_app]},
+      {mod, {ch_sup, {app_chain_error2, 21,21}}}]}.
+
 app_group_leader() ->
     {application, group_leader,
      [{description, "GROUP_LEADER  CXC 138 11"},
@@ -2374,6 +2471,12 @@ w_app7(Fd) ->
 w_app8(Fd) ->
     io:format(Fd, "~p.\n", [app8()]).
 
+w_app9(Fd) ->
+    io:format(Fd, "~p.\n", [app9()]).
+
+w_app10_dep9(Fd) ->
+    io:format(Fd, "~p.\n", [app10_dep9()]).
+
 w_app_start_error(Fd) ->
     io:format(Fd, "~p.\n", [app_start_error()]).