From 352bc190e518301421970399cac57ec199daaf66 Mon Sep 17 00:00:00 2001
From: Vincent Latombe <vincent@latombe.net>
Date: Tue, 3 Oct 2023 12:32:50 +0200
Subject: [PATCH] [JENKINS-72111] Add Lifecycle#set

---
 .../main/java/hudson/lifecycle/Lifecycle.java | 20 +++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/core/src/main/java/hudson/lifecycle/Lifecycle.java b/core/src/main/java/hudson/lifecycle/Lifecycle.java
index da629dce94e1..be4b03560a13 100644
--- a/core/src/main/java/hudson/lifecycle/Lifecycle.java
+++ b/core/src/main/java/hudson/lifecycle/Lifecycle.java
@@ -28,18 +28,22 @@
 import edu.umd.cs.findbugs.annotations.NonNull;
 import hudson.ExtensionPoint;
 import hudson.Functions;
+import hudson.PluginManager;
 import hudson.Util;
 import java.io.File;
 import java.io.IOException;
 import java.io.UncheckedIOException;
 import java.lang.reflect.InvocationTargetException;
 import java.nio.file.Files;
+import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 import jenkins.model.Jenkins;
 import jenkins.util.SystemProperties;
 import org.apache.commons.io.FileUtils;
+import org.kohsuke.accmod.Restricted;
+import org.kohsuke.accmod.restrictions.Beta;
 
 /**
  * Provides the capability for starting/stopping/restarting/uninstalling Hudson.
@@ -57,9 +61,8 @@ public abstract class Lifecycle implements ExtensionPoint {
 
     /**
      * Gets the singleton instance.
-     *
-     * @return never null
      */
+    @NonNull
     public static synchronized Lifecycle get() {
         if (INSTANCE == null) {
             Lifecycle instance;
@@ -136,6 +139,19 @@ public void verifyRestartable() throws RestartNotSupportedException {
         return INSTANCE;
     }
 
+    /**
+     * Sets the singleton instance.
+     * Appropriate for implementations defined in plugins,
+     * since {@link #get} may be called before plugins are initialized,
+     * and so it is not safe to pass a plugin-defined class to the system property {@code hudson.lifecycle}
+     * despite the use of {@link PluginManager#uberClassLoader}.
+     * @since TODO
+     */
+    @Restricted(Beta.class)
+    public static synchronized void set(@NonNull Lifecycle lifecycle) {
+        INSTANCE = Objects.requireNonNull(lifecycle);
+    }
+
     /**
      * If the location of {@code jenkins.war} is known in this life cycle,
      * return it location. Otherwise return null to indicate that it is unknown.