[GR-72496] Add uncaught exception handler to threads started by Stressor.

PullRequest: graal/23285

Author: christianhaeubl

substratevm/src/com.oracle.svm.test/src/com/oracle/svm/test/jfr/Stressor.java

@@ -26,14 +26,20 @@
 
 package com.oracle.svm.test.jfr;
 
+import java.util.concurrent.atomic.AtomicReference;
+
 /**
  * Class to help run multiple threads executing some task.
  */
 public class Stressor {
-    public static void execute(int numberOfThreads, Runnable task) {
+    public static void execute(int numberOfThreads, Runnable task) throws Throwable {
         Thread[] threads = new Thread[numberOfThreads];
+        StoreUncaughtException[] uncaughtExceptions = new StoreUncaughtException[numberOfThreads];
+
         for (int i = 0; i < numberOfThreads; i++) {
             threads[i] = new Thread(task);
+            uncaughtExceptions[i] = new StoreUncaughtException();
+            threads[i].setUncaughtExceptionHandler(uncaughtExceptions[i]);
         }
 
         for (int i = 0; i < numberOfThreads; i++) {
@@ -43,9 +49,28 @@ public static void execute(int numberOfThreads, Runnable task) {
         for (int i = 0; i < numberOfThreads; i++) {
             try {
                 threads[i].join();
+
+                /* Rethrow any uncaught exceptions. */
+                Throwable throwable = uncaughtExceptions[i].get();
+                if (throwable != null) {
+                    throw throwable;
+                }
             } catch (InterruptedException e) {
                 throw new RuntimeException(e);
             }
         }
     }
+
+    private static final class StoreUncaughtException implements Thread.UncaughtExceptionHandler {
+        private final AtomicReference<Throwable> throwable = new AtomicReference<>();
+
+        public Throwable get() {
+            return throwable.get();
+        }
+
+        @Override
+        public void uncaughtException(Thread t, Throwable e) {
+            this.throwable.set(e);
+        }
+    }
 }

substratevm/src/com.oracle.svm.test/src/com/oracle/svm/test/jfr/TestJfrStreamingBasic.java

@@ -77,7 +77,12 @@ public void test() throws Throwable {
         stream.onFlush(() -> {
             if (firstFlush) {
                 firstFlush = false;
-                Stressor.execute(THREADS, eventEmitter);
+
+                try {
+                    Stressor.execute(THREADS, eventEmitter);
+                } catch (Throwable throwable) {
+                    throw new RuntimeException(throwable);
+                }
             }
         });
 

substratevm/src/com.oracle.svm.test/src/com/oracle/svm/test/jfr/TestJfrStreamingCount.java

@@ -86,14 +86,14 @@ public void test() throws Throwable {
         Stressor.execute(THREADS, eventEmitter);
 
         waitUntilTrue(() -> emittedEventsPerType.get() >= EXPECTED_EVENTS_PER_TYPE);
-        waitUntilTrue(() -> classEvents.get() >= EXPECTED_EVENTS_PER_TYPE);
         waitUntilTrue(() -> integerEvents.get() >= EXPECTED_EVENTS_PER_TYPE);
         waitUntilTrue(() -> stringEvents.get() >= EXPECTED_EVENTS_PER_TYPE);
+        waitUntilTrue(() -> classEvents.get() >= EXPECTED_EVENTS_PER_TYPE);
 
         assertEquals(EXPECTED_EVENTS_PER_TYPE, emittedEventsPerType.get());
-        assertEquals(EXPECTED_EVENTS_PER_TYPE, classEvents.get());
         assertEquals(EXPECTED_EVENTS_PER_TYPE, integerEvents.get());
         assertEquals(EXPECTED_EVENTS_PER_TYPE, stringEvents.get());
+        assertEquals(EXPECTED_EVENTS_PER_TYPE, classEvents.get());
 
         stopStream(stream, TestJfrStreamingCount::validateEvents);
     }