fix: concurrent modification when getting event sources (v5) (#2572)

Author: csviri

Diff for: operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/event/EventSources.java

@@ -1,10 +1,12 @@
 package io.javaoperatorsdk.operator.processing.event;
 
+
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentNavigableMap;
 import java.util.concurrent.ConcurrentSkipListMap;
 import java.util.stream.Stream;
@@ -33,7 +35,8 @@ public void add(EventSource eventSource) {
           + " is already registered with name: " + name);
     }
     sourceByName.put(name, eventSource);
-    sources.computeIfAbsent(keyFor(eventSource), k -> new HashMap<>()).put(name, eventSource);
+    sources.computeIfAbsent(keyFor(eventSource), k -> new ConcurrentHashMap<>()).put(name,
+        eventSource);
   }
 
   public EventSource remove(String name) {
@@ -144,7 +147,6 @@ public <S> List<EventSource<S, P>> getEventSources(Class<S> dependentType) {
     if (sourcesForType == null) {
       return Collections.emptyList();
     }
-
     return sourcesForType.values().stream()
         .map(es -> (EventSource<S, P>) es).toList();
   }

Diff for: operator-framework-core/src/test/java/io/javaoperatorsdk/operator/processing/event/EventSourceManagerTest.java

@@ -36,6 +36,7 @@ class EventSourceManagerTest {
   public void registersEventSource() {
     EventSource eventSource = mock(EventSource.class);
     when(eventSource.resourceType()).thenReturn(EventSource.class);
+    when(eventSource.name()).thenReturn("name1");
 
     eventSourceManager.registerEventSource(eventSource);
 
@@ -95,6 +96,7 @@ void retrievingEventSourceForClassShouldWork() {
 
     ManagedInformerEventSource eventSource = mock(ManagedInformerEventSource.class);
     when(eventSource.resourceType()).thenReturn(String.class);
+    when(eventSource.name()).thenReturn("name1");
     manager.registerEventSource(eventSource);
 
     var source = manager.getEventSourceFor(String.class);

Diff for: operator-framework-core/src/test/java/io/javaoperatorsdk/operator/processing/event/EventSourcesTest.java

@@ -1,5 +1,10 @@
 package io.javaoperatorsdk.operator.processing.event;
 
+import java.util.ConcurrentModificationException;
+import java.util.concurrent.Phaser;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.stream.IntStream;
+
 import org.junit.jupiter.api.Test;
 
 import io.fabric8.kubernetes.api.model.ConfigMap;
@@ -177,7 +182,43 @@ void getEventSourcesShouldWork() {
     assertThat(eventSources.getEventSources(Service.class)).isEmpty();
   }
 
-
+  @Test
+  void testConcurrentAddRemoveAndGet() throws InterruptedException {
+
+    final var concurrentExceptionFound = new AtomicBoolean(false);
+
+    for (int i = 0; i < 1000 && !concurrentExceptionFound.get(); i++) {
+      final var eventSources = new EventSources();
+      var eventSourceList =
+          IntStream.range(1, 20).mapToObj(n -> eventSourceMockWithName(EventSource.class,
+              "name" + n, HasMetadata.class)).toList();
+
+      IntStream.range(1, 10).forEach(n -> eventSources.add(eventSourceList.get(n - 1)));
+
+      var phaser = new Phaser(2);
+
+      var t1 = new Thread(() -> {
+        phaser.arriveAndAwaitAdvance();
+        IntStream.range(11, 20).forEach(n -> eventSources.add(eventSourceList.get(n - 1)));
+      });
+      var t2 = new Thread(() -> {
+        phaser.arriveAndAwaitAdvance();
+        try {
+          eventSources.getEventSources(eventSourceList.get(0).resourceType());
+        } catch (ConcurrentModificationException e) {
+          concurrentExceptionFound.set(true);
+        }
+      });
+      t1.start();
+      t2.start();
+      t1.join();
+      t2.join();
+    }
+
+    assertThat(concurrentExceptionFound)
+        .withFailMessage("ConcurrentModificationException thrown")
+        .isFalse();
+  }
 
   <T extends EventSource> EventSource eventSourceMockWithName(Class<T> clazz, String name,
       Class resourceType) {