From e7f91bab78b05460966f24eded91632776c17d1a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Deleuze?= <sdeleuze@vmware.com>
Date: Thu, 17 Nov 2022 15:43:22 +0100
Subject: [PATCH] Refine BackgroundPreinitializer code reachability

GraalVM code reachability algorithm is not able to evaluate at build
time that ENABLED static field is always false in a native image,
shipping unreachable code.

Before this commit, building a native image with -H:+PrintAnalysisCallTree
shows that the following methods are included:
- BackgroundPreinitializer$1.<init>(BackgroundPreinitializer):void
- BackgroundPreinitializer$1.run():void
- BackgroundPreinitializer$1.runSafely(Runnable):void
- BackgroundPreinitializer$CharsetInitializer.run():void
- BackgroundPreinitializer$ConversionServiceInitializer.run():void
- BackgroundPreinitializer$JacksonInitializer.run():void
- BackgroundPreinitializer$MessageConverterInitializer.run():void
- BackgroundPreinitializer$ValidationInitializer.run():void
- BackgroundPreinitializer.<clinit>():void
- BackgroundPreinitializer.getOrder():int
- BackgroundPreinitializer.onApplicationEvent(ApplicationEvent):void
- BackgroundPreinitializer.onApplicationEvent(SpringApplicationEvent):void
- BackgroundPreinitializer.performPreinitialization():void

After this commit, only those are included:
- BackgroundPreinitializer.<clinit>():void
- BackgroundPreinitializer.getOrder():int
- BackgroundPreinitializer.onApplicationEvent(ApplicationEvent):void
- BackgroundPreinitializer.onApplicationEvent(SpringApplicationEvent):void

See gh-33240
---
 .../boot/autoconfigure/BackgroundPreinitializer.java   | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/BackgroundPreinitializer.java b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/BackgroundPreinitializer.java
index 56268dbf59c..def33294a41 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/BackgroundPreinitializer.java
+++ b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/BackgroundPreinitializer.java
@@ -64,12 +64,8 @@ public class BackgroundPreinitializer implements ApplicationListener<SpringAppli
 
 	private static final CountDownLatch preinitializationComplete = new CountDownLatch(1);
 
-	private static final boolean ENABLED;
-
-	static {
-		ENABLED = !Boolean.getBoolean(IGNORE_BACKGROUNDPREINITIALIZER_PROPERTY_NAME) && !NativeDetector.inNativeImage()
-				&& Runtime.getRuntime().availableProcessors() > 1;
-	}
+	private static final boolean ENABLED = !Boolean.getBoolean(IGNORE_BACKGROUNDPREINITIALIZER_PROPERTY_NAME)
+			&& Runtime.getRuntime().availableProcessors() > 1;
 
 	@Override
 	public int getOrder() {
@@ -78,7 +74,7 @@ public class BackgroundPreinitializer implements ApplicationListener<SpringAppli
 
 	@Override
 	public void onApplicationEvent(SpringApplicationEvent event) {
-		if (!ENABLED) {
+		if (!ENABLED || NativeDetector.inNativeImage()) {
 			return;
 		}
 		if (event instanceof ApplicationEnvironmentPreparedEvent