--- jsr166/src/test/tck/AbstractQueuedSynchronizerTest.java	2017/07/17 21:01:30	1.57
+++ jsr166/src/test/tck/AbstractQueuedSynchronizerTest.java	2018/07/22 22:13:55	1.65
@@ -9,13 +9,14 @@
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static java.util.concurrent.TimeUnit.NANOSECONDS;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashSet;
+import java.util.concurrent.ThreadLocalRandom;
 import java.util.concurrent.locks.AbstractQueuedSynchronizer;
 import java.util.concurrent.locks.AbstractQueuedSynchronizer.ConditionObject;
 
-import junit.framework.AssertionFailedError;
 import junit.framework.Test;
 import junit.framework.TestSuite;
 
@@ -34,6 +35,9 @@ public class AbstractQueuedSynchronizerT
      * methods/features of AbstractQueuedSynchronizer are tested via
      * other test classes, including those for ReentrantLock,
      * ReentrantReadWriteLock, and Semaphore.
+     *
+     * Unlike the javadoc sample, we don't track owner thread via
+     * AbstractOwnableSynchronizer methods.
      */
     static class Mutex extends AbstractQueuedSynchronizer {
         /** An eccentric value for locked synchronizer state. */
@@ -41,18 +45,19 @@ public class AbstractQueuedSynchronizerT
 
         static final int UNLOCKED = 0;
 
+        /** Owner thread is untracked, so this is really just isLocked(). */
         @Override public boolean isHeldExclusively() {
             int state = getState();
             assertTrue(state == UNLOCKED || state == LOCKED);
             return state == LOCKED;
         }
 
-        @Override public boolean tryAcquire(int acquires) {
+        @Override protected boolean tryAcquire(int acquires) {
             assertEquals(LOCKED, acquires);
             return compareAndSetState(UNLOCKED, LOCKED);
         }
 
-        @Override public boolean tryRelease(int releases) {
+        @Override protected boolean tryRelease(int releases) {
             if (getState() != LOCKED) throw new IllegalMonitorStateException();
             assertEquals(LOCKED, releases);
             setState(UNLOCKED);
@@ -83,13 +88,14 @@ public class AbstractQueuedSynchronizerT
             release(LOCKED);
         }
 
+        /** Faux-Implements Lock.newCondition(). */
         public ConditionObject newCondition() {
             return new ConditionObject();
         }
     }
 
     /**
-     * A simple latch class, to test shared mode.
+     * A minimal latch class, to test shared mode.
      */
     static class BooleanLatch extends AbstractQueuedSynchronizer {
         public boolean isSignalled() { return getState() != 0; }
@@ -138,7 +144,7 @@ public class AbstractQueuedSynchronizerT
         long startTime = System.nanoTime();
         while (!sync.isQueued(t)) {
             if (millisElapsedSince(startTime) > LONG_DELAY_MS)
-                throw new AssertionFailedError("timed out");
+                throw new AssertionError("timed out");
             Thread.yield();
         }
         assertTrue(t.isAlive());
@@ -222,8 +228,8 @@ public class AbstractQueuedSynchronizerT
             assertTrue(c.await(timeoutMillis, MILLISECONDS));
             break;
         case awaitNanos:
-            long nanosTimeout = MILLISECONDS.toNanos(timeoutMillis);
-            long nanosRemaining = c.awaitNanos(nanosTimeout);
+            long timeoutNanos = MILLISECONDS.toNanos(timeoutMillis);
+            long nanosRemaining = c.awaitNanos(timeoutNanos);
             assertTrue(nanosRemaining > 0);
             break;
         case awaitUntil:
@@ -250,8 +256,8 @@ public class AbstractQueuedSynchronizerT
                 break;
             case awaitNanos:
                 startTime = System.nanoTime();
-                long nanosTimeout = MILLISECONDS.toNanos(timeoutMillis);
-                long nanosRemaining = c.awaitNanos(nanosTimeout);
+                long timeoutNanos = MILLISECONDS.toNanos(timeoutMillis);
+                long nanosRemaining = c.awaitNanos(timeoutNanos);
                 assertTrue(nanosRemaining <= 0);
                 assertTrue(nanosRemaining > -MILLISECONDS.toNanos(LONG_DELAY_MS));
                 assertTrue(millisElapsedSince(startTime) >= timeoutMillis);
@@ -1254,4 +1260,104 @@ public class AbstractQueuedSynchronizerT
         sync.release();
     }
 
+    /**
+     * JDK-8191483: AbstractQueuedSynchronizer cancel/cancel race
+     * ant -Djsr166.tckTestClass=AbstractQueuedSynchronizerTest -Djsr166.methodFilter=testCancelCancelRace -Djsr166.runsPerTest=100 tck
+     */
+    public void testCancelCancelRace() throws InterruptedException {
+        class Sync extends AbstractQueuedSynchronizer {
+            protected boolean tryAcquire(int acquires) {
+                return !hasQueuedPredecessors() && compareAndSetState(0, 1);
+            }
+            protected boolean tryRelease(int releases) {
+                return compareAndSetState(1, 0);
+            }
+        }
+
+        Sync s = new Sync();
+        s.acquire(1);           // acquire to force other threads to enqueue
+
+        // try to trigger double cancel race with two background threads
+        ArrayList<Thread> threads = new ArrayList<>();
+        Runnable failedAcquire = () -> {
+            try {
+                s.acquireInterruptibly(1);
+                shouldThrow();
+            } catch (InterruptedException success) {}
+        };
+        for (int i = 0; i < 2; i++) {
+            Thread thread = new Thread(failedAcquire);
+            thread.start();
+            threads.add(thread);
+        }
+        Thread.sleep(100);
+        for (Thread thread : threads) thread.interrupt();
+        for (Thread thread : threads) awaitTermination(thread);
+
+        s.release(1);
+
+        // no one holds lock now, we should be able to acquire
+        if (!s.tryAcquire(1))
+            throw new RuntimeException(
+                String.format(
+                    "Broken: hasQueuedPredecessors=%s hasQueuedThreads=%s queueLength=%d firstQueuedThread=%s",
+                    s.hasQueuedPredecessors(),
+                    s.hasQueuedThreads(),
+                    s.getQueueLength(),
+                    s.getFirstQueuedThread()));
+    }
+
+    /**
+     * Tests scenario for
+     * JDK-8191937: Lost interrupt in AbstractQueuedSynchronizer when tryAcquire methods throw
+     */
+    public void testInterruptedFailingAcquire() throws InterruptedException {
+        final RuntimeException ex = new RuntimeException();
+
+        // A synchronizer only offering a choice of failure modes
+        class Sync extends AbstractQueuedSynchronizer {
+            boolean pleaseThrow;
+            @Override protected boolean tryAcquire(int ignored) {
+                if (pleaseThrow) throw ex;
+                return false;
+            }
+            @Override protected int tryAcquireShared(int ignored) {
+                if (pleaseThrow) throw ex;
+                return -1;
+            }
+            @Override protected boolean tryRelease(int ignored) {
+                return true;
+            }
+            @Override protected boolean tryReleaseShared(int ignored) {
+                return true;
+            }
+        }
+
+        final Sync s = new Sync();
+
+        final Thread thread = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                try {
+                    if (ThreadLocalRandom.current().nextBoolean())
+                        s.acquire(1);
+                    else
+                        s.acquireShared(1);
+                    shouldThrow();
+                } catch (Throwable t) {
+                    assertSame(ex, t);
+                    assertTrue(Thread.interrupted());
+                }
+            }});
+        waitForThreadToEnterWaitState(thread);
+        assertSame(thread, s.getFirstQueuedThread());
+        assertTrue(s.hasQueuedPredecessors());
+        assertTrue(s.hasQueuedThreads());
+        assertEquals(1, s.getQueueLength());
+
+        s.pleaseThrow = true;
+        thread.interrupt();
+        s.release(1);
+        awaitTermination(thread);
+    }
+
 }