File 3111-stdlib-Add-error-return-value-for-init.patch of Package erlang

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File 3111-stdlib-Add-error-return-value-for-init.patch of Package erlang

From ddfd7da15cd51cf5dccd71ad772a302449a5b73a Mon Sep 17 00:00:00 2001
From: Micael Karlberg <bmk@erlang.org>
Date: Tue, 31 Jan 2023 10:15:19 +0100
Subject: [PATCH 1/3] [stdlib] Add error return value for init

Add a new "legal" return value for Module:init/1 (for both
gen_server and gen_statem); {error, Reason}
This should have same effect as ignore, except that the return value
should be '{error, Reason}' instead of 'ignore'.

OTP-18423
---
 lib/stdlib/src/gen_server.erl | 15 ++++++++++++---
 lib/stdlib/src/gen_statem.erl | 17 ++++++++++++++---
 2 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/lib/stdlib/src/gen_server.erl b/lib/stdlib/src/gen_server.erl
index d920aa9fcd..3f355a5b53 100644
--- a/lib/stdlib/src/gen_server.erl
+++ b/lib/stdlib/src/gen_server.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2022. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2023. All Rights Reserved.
 %%
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -169,7 +169,7 @@
 
 -callback init(Args :: term()) ->
     {ok, State :: term()} | {ok, State :: term(), timeout() | hibernate | {continue, term()}} |
-    {stop, Reason :: term()} | ignore.
+    {stop, Reason :: term()} | ignore | {error, Reason :: term()}.
 -callback handle_call(Request :: term(), From :: from(),
                       State :: term()) ->
     {reply, Reply :: term(), NewState :: term()} |
@@ -851,6 +851,13 @@ init_it(Starter, Parent, Name0, Mod, Args, Options) ->
 	    gen:unregister_name(Name0),
 	    proc_lib:init_ack(Starter, {error, Reason}),
 	    exit(Reason);
+	{ok, {error, _Reason} = ERROR} ->
+            %% The point of this clause is that we shall have a silent/graceful
+            %% termination. The error reason will be returned to the
+            %% 'Starter' ({error, Reason}), but *no* crash report.
+	    gen:unregister_name(Name0),
+	    proc_lib:init_ack(Starter, ERROR),
+	    exit(normal);
 	{ok, ignore} ->
 	    gen:unregister_name(Name0),
 	    proc_lib:init_ack(Starter, ignore),
@@ -861,7 +868,8 @@ init_it(Starter, Parent, Name0, Mod, Args, Options) ->
 	    exit(Error);
 	{'EXIT', Class, Reason, Stacktrace} ->
 	    gen:unregister_name(Name0),
-	    proc_lib:init_ack(Starter, {error, terminate_reason(Class, Reason, Stacktrace)}),
+            ActualReason = terminate_reason(Class, Reason, Stacktrace),
+	    proc_lib:init_ack(Starter, {error, ActualReason}),
 	    erlang:raise(Class, Reason, Stacktrace)
     end.
 init_it(Mod, Args) ->
@@ -872,6 +880,7 @@ init_it(Mod, Args) ->
         Class:R:S -> {'EXIT', Class, R, S}
     end.
 
+
 %%%========================================================================
 %%% Internal functions
 %%%========================================================================
diff --git a/lib/stdlib/src/gen_statem.erl b/lib/stdlib/src/gen_statem.erl
index e3fa14a8a8..39cba737ef 100644
--- a/lib/stdlib/src/gen_statem.erl
+++ b/lib/stdlib/src/gen_statem.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 2016-2022. All Rights Reserved.
+%% Copyright Ericsson AB 2016-2023. All Rights Reserved.
 %%
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -97,6 +97,9 @@
     start_ret/0,
     start_mon_ret/0]).
 
+%% -define(DBG(T), erlang:display({{self(), ?MODULE, ?LINE, ?FUNCTION_NAME}, T})).
+
+
 %%%==========================================================================
 %%% Interface functions.
 %%%==========================================================================
@@ -225,8 +228,9 @@
     {ok, State :: StateType, Data :: DataType} |
     {ok, State :: StateType, Data :: DataType,
      Actions :: [action()] | action()} |
-    'ignore' |
-    {'stop', Reason :: term()}.
+        'ignore' |
+        {'stop', Reason :: term()} |
+        {'error', Reason :: term()}.
 
 %% Old, not advertised
 -type state_function_result() ::
@@ -1056,6 +1060,13 @@ init_result(
 	    gen:unregister_name(ServerRef),
 	    proc_lib:init_ack(Starter, {error,Reason}),
 	    exit(Reason);
+	{error, _Reason} = ERROR ->
+            %% The point of this clause is that we shall have a *silent*
+            %% termination. The error reason will be returned to the
+            %% 'Starter' ({error, Reason}), but *no* crash report.
+	    gen:unregister_name(ServerRef),
+	    proc_lib:init_ack(Starter, ERROR),
+	    exit(normal);
 	ignore ->
 	    gen:unregister_name(ServerRef),
 	    proc_lib:init_ack(Starter, ignore),
-- 
2.35.3

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File 3111-stdlib-Add-error-return-value-for-init.patch of Package erlang

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