8303742: CompletableFuture.orTimeout leaks if the future completes exceptionally

8304557: java/util/concurrent/CompletableFuture/CompletableFutureOrTimeoutExceptionallyTest.java times out

Reviewed-by: phh
Backport-of: ded6a81

Author: Ben Taylor

src/java.base/share/classes/java/util/concurrent/CompletableFuture.java

@@ -2891,7 +2891,7 @@ static final class Canceller implements BiConsumer<Object, Throwable> {
         final Future<?> f;
         Canceller(Future<?> f) { this.f = f; }
         public void accept(Object ignore, Throwable ex) {
-            if (ex == null && f != null && !f.isDone())
+            if (f != null && !f.isDone())
                 f.cancel(false);
         }
     }

test/jdk/java/util/concurrent/CompletableFuture/CompletableFutureOrTimeoutExceptionallyTest.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8303742
+ * @summary CompletableFuture.orTimeout can leak memory if completed exceptionally
+ * @modules java.base/java.util.concurrent:open
+ * @run junit/othervm -Xmx128m CompletableFutureOrTimeoutExceptionallyTest
+ */
+
+import java.time.Duration;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class CompletableFutureOrTimeoutExceptionallyTest {
+    static final BlockingQueue<Runnable> delayerQueue;
+    static {
+        try {
+            var delayerClass = Class.forName("java.util.concurrent.CompletableFuture$Delayer",
+                                             true,
+                                             CompletableFuture.class.getClassLoader());
+            var delayerField = delayerClass.getDeclaredField("delayer");
+            delayerField.setAccessible(true);
+            delayerQueue = ((ScheduledThreadPoolExecutor)delayerField.get(null)).getQueue();
+        } catch (Throwable t) {
+            throw new ExceptionInInitializerError(t);
+        }
+    }
+
+    /**
+     * Test that orTimeout task is cancelled if the CompletableFuture is completed Exceptionally
+     */
+    @Test
+    void testOrTimeoutWithCompleteExceptionallyDoesNotLeak() throws InterruptedException {
+        assertTrue(delayerQueue.peek() == null);
+        var future = new CompletableFuture<>().orTimeout(12, TimeUnit.HOURS);
+        assertTrue(delayerQueue.peek() != null);
+        future.completeExceptionally(new RuntimeException("This is fine"));
+        while (delayerQueue.peek() != null) {
+            Thread.sleep(100);
+        };
+    }
+
+    /**
+     * Test that the completeOnTimeout task is cancelled if the CompletableFuture is completed Exceptionally
+     */
+    @Test
+    void testCompleteOnTimeoutWithCompleteExceptionallyDoesNotLeak() throws InterruptedException {
+        assertTrue(delayerQueue.peek() == null);
+        var future = new CompletableFuture<>().completeOnTimeout(null, 12, TimeUnit.HOURS);
+        assertTrue(delayerQueue.peek() != null);
+        future.completeExceptionally(new RuntimeException("This is fine"));
+        while (delayerQueue.peek() != null) {
+            Thread.sleep(100);
+        };
+    }
+}