From e4fe5042e4f591b1e09ae4ec78354a8a5cf57370 Mon Sep 17 00:00:00 2001
From: Jesse Glick <jglick@cloudbees.com>
Date: Wed, 8 Nov 2023 08:39:28 -0500
Subject: [PATCH] Temporary memory leak in `FutureImpl.executors` (#8640)

* Temporary memory leak in `FutureImpl.executors`

* https://github.com/jenkinsci/jenkins-test-harness/pull/669 released

* Skip new test on Windows https://github.com/jenkinsci/jenkins/pull/8640#discussion_r1373797374
---
 .../java/hudson/model/queue/FutureImpl.java   |  4 ++++
 .../hudson/model/queue/WorkUnitContext.java   |  1 +
 .../test/java/hudson/model/ComputerTest.java  | 24 +++++++++++++++++++
 3 files changed, 29 insertions(+)

diff --git a/core/src/main/java/hudson/model/queue/FutureImpl.java b/core/src/main/java/hudson/model/queue/FutureImpl.java
index f6bba013f2..d57453ece5 100644
--- a/core/src/main/java/hudson/model/queue/FutureImpl.java
+++ b/core/src/main/java/hudson/model/queue/FutureImpl.java
@@ -95,4 +95,8 @@ public final class FutureImpl extends AsyncFutureImpl<Executable> implements Que
     synchronized void addExecutor(@NonNull Executor executor) {
         this.executors.add(executor);
     }
+
+    synchronized void finished() {
+        executors.clear();
+    }
 }
diff --git a/core/src/main/java/hudson/model/queue/WorkUnitContext.java b/core/src/main/java/hudson/model/queue/WorkUnitContext.java
index 31829ba7dd..83320ab5d4 100644
--- a/core/src/main/java/hudson/model/queue/WorkUnitContext.java
+++ b/core/src/main/java/hudson/model/queue/WorkUnitContext.java
@@ -190,6 +190,7 @@ public final class WorkUnitContext {
                         }
                     }
                 }
+                future.finished();
             }
         }
     }
diff --git a/test/src/test/java/hudson/model/ComputerTest.java b/test/src/test/java/hudson/model/ComputerTest.java
index b0ce7a7546..a3392ee448 100644
--- a/test/src/test/java/hudson/model/ComputerTest.java
+++ b/test/src/test/java/hudson/model/ComputerTest.java
@@ -31,6 +31,7 @@ import static org.hamcrest.Matchers.anyOf;
 import static org.hamcrest.Matchers.containsInAnyOrder;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.isA;
 import static org.hamcrest.Matchers.not;
 import static org.hamcrest.Matchers.nullValue;
@@ -39,12 +40,16 @@ import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assume.assumeThat;
 
 import hudson.ExtensionList;
+import hudson.Functions;
 import hudson.diagnosis.OldDataMonitor;
+import hudson.remoting.Channel;
 import hudson.slaves.DumbSlave;
 import hudson.slaves.OfflineCause;
 import java.io.File;
+import java.lang.ref.WeakReference;
 import java.net.HttpURLConnection;
 import java.nio.charset.StandardCharsets;
 import java.util.Map;
@@ -66,6 +71,7 @@ import org.jvnet.hudson.test.Issue;
 import org.jvnet.hudson.test.JenkinsRule;
 import org.jvnet.hudson.test.JenkinsRule.WebClient;
 import org.jvnet.hudson.test.LoggerRule;
+import org.jvnet.hudson.test.MemoryAssert;
 import org.jvnet.hudson.test.MockAuthorizationStrategy;
 import org.jvnet.hudson.test.MockFolder;
 import org.jvnet.hudson.test.SmokeTest;
@@ -263,4 +269,22 @@ public class ComputerTest {
         j.assertBuildStatus(Result.FAILURE, j.waitForCompletion(b));
     }
 
+    @Test
+    public void computersCollected() throws Exception {
+        assumeThat("Seems to crash the test JVM at least in CI", Functions.isWindows(), is(false));
+        DumbSlave agent = j.createOnlineSlave();
+        FreeStyleProject p = j.createFreeStyleProject();
+        p.setAssignedNode(agent);
+        j.buildAndAssertSuccess(p);
+        Computer computer = agent.toComputer();
+        WeakReference<Computer> computerRef = new WeakReference<>(computer);
+        WeakReference<Channel> channelRef = new WeakReference<>((Channel) computer.getChannel());
+        computer.disconnect(null);
+        computer = null;
+        j.jenkins.removeNode(agent);
+        agent = null;
+        MemoryAssert.assertGC(computerRef, false);
+        MemoryAssert.assertGC(channelRef, false);
+    }
+
 }