File 0454-gen_event-eliminate-selective-receive-in-fetch_msg-6.patch of Package erlang

From 9074e5f58bd3e636d1719c128e0c477b60dcf9b5 Mon Sep 17 00:00:00 2001
From: Mikael Pettersson <mikael.pettersson@klarna.com>
Date: Thu, 4 Aug 2022 18:50:26 +0200
Subject: [PATCH] gen_event: eliminate selective-receive in fetch_msg/6

Perform a non-selective receive with timeout, and pass the
message to factored-out decode_msg/7, similar to gen_server.
---
 lib/stdlib/src/gen_event.erl | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/lib/stdlib/src/gen_event.erl b/lib/stdlib/src/gen_event.erl
index 20d9910374..fd4b5d9add 100644
--- a/lib/stdlib/src/gen_event.erl
+++ b/lib/stdlib/src/gen_event.erl
@@ -499,19 +499,25 @@ wake_hib(Parent, ServerName, MSL, HibernateAfterTimeout, Debug) ->
 
 fetch_msg(Parent, ServerName, MSL, HibernateAfterTimeout, Debug, Hib) ->
     receive
+	Msg ->
+	    decode_msg(Msg, Parent, ServerName, MSL, HibernateAfterTimeout, Debug, Hib)
+    after HibernateAfterTimeout ->
+	    loop(Parent, ServerName, MSL, HibernateAfterTimeout, Debug, true)
+    end.
+
+decode_msg(Msg, Parent, ServerName, MSL, HibernateAfterTimeout, Debug, Hib) ->
+    case Msg of
 	{system, From, Req} ->
 	    sys:handle_system_msg(Req, From, Parent, ?MODULE, Debug,
 				  [ServerName, MSL, HibernateAfterTimeout, Hib],Hib);
 	{'EXIT', Parent, Reason} ->
 	    terminate_server(Reason, Parent, MSL, ServerName);
-	Msg when Debug =:= [] ->
+	_Msg when Debug =:= [] ->
 	    handle_msg(Msg, Parent, ServerName, MSL, HibernateAfterTimeout, []);
-	Msg ->
+	_Msg ->
 	    Debug1 = sys:handle_debug(Debug, fun print_event/3,
 				      ServerName, {in, Msg}),
 	    handle_msg(Msg, Parent, ServerName, MSL, HibernateAfterTimeout, Debug1)
-    after HibernateAfterTimeout ->
-	    loop(Parent, ServerName, MSL, HibernateAfterTimeout, Debug, true)
     end.
 
 handle_msg(Msg, Parent, ServerName, MSL, HibernateAfterTimeout, Debug) ->
-- 
2.35.3