From 5d9043f1752400e1abf1696c33dbd6df1f3749da Mon Sep 17 00:00:00 2001
From: tison <wander4096@gmail.com>
Date: Sun, 22 Dec 2024 02:38:58 +0800
Subject: [PATCH] add test

Signed-off-by: tison <wander4096@gmail.com>
---
 .mvn/extensions.xml                           |  2 +-
 .../framework/recipes/leader/LeaderLatch.java | 11 ++--
 .../recipes/leader/TestLeaderLatch.java       | 57 +++++++++++++++++++
 3 files changed, 65 insertions(+), 5 deletions(-)

diff --git a/.mvn/extensions.xml b/.mvn/extensions.xml
index 1ca382883..98c357118 100644
--- a/.mvn/extensions.xml
+++ b/.mvn/extensions.xml
@@ -24,7 +24,7 @@
     <extension>
         <groupId>com.gradle</groupId>
         <artifactId>develocity-maven-extension</artifactId>
-        <version>1.21.4</version>
+        <version>1.23</version>
     </extension>
     <extension>
         <groupId>com.gradle</groupId>
diff --git a/curator-recipes/src/main/java/org/apache/curator/framework/recipes/leader/LeaderLatch.java b/curator-recipes/src/main/java/org/apache/curator/framework/recipes/leader/LeaderLatch.java
index a1cddde7e..4226e8819 100644
--- a/curator-recipes/src/main/java/org/apache/curator/framework/recipes/leader/LeaderLatch.java
+++ b/curator-recipes/src/main/java/org/apache/curator/framework/recipes/leader/LeaderLatch.java
@@ -624,18 +624,21 @@ public void processResult(CuratorFramework client, CuratorEvent event) throws Ex
         client.getChildren().inBackground(callback).forPath(ZKPaths.makePath(latchPath, null));
     }
 
+    @VisibleForTesting
+    volatile CountDownLatch debugHandleReconnectedLatch = null;
+
     @VisibleForTesting
     protected void handleStateChange(ConnectionState newState) {
         switch (newState) {
             case RECONNECTED: {
                 try {
-                    if (client.getConnectionStateErrorPolicy().isErrorState(ConnectionState.SUSPENDED)
-                            || !hasLeadership.get()) {
-                        getChildren();
+                    if (debugHandleReconnectedLatch != null) {
+                        debugHandleReconnectedLatch.await();
                     }
+                    getChildren();
                 } catch (Exception e) {
                     ThreadUtils.checkInterrupted(e);
-                    log.error("failed to reset leader latch", e);
+                    log.error("failed to recheck leadership on reconnected", e);
                     setLeadership(false);
                 }
                 break;
diff --git a/curator-recipes/src/test/java/org/apache/curator/framework/recipes/leader/TestLeaderLatch.java b/curator-recipes/src/test/java/org/apache/curator/framework/recipes/leader/TestLeaderLatch.java
index 528b317ff..0dc375d16 100644
--- a/curator-recipes/src/test/java/org/apache/curator/framework/recipes/leader/TestLeaderLatch.java
+++ b/curator-recipes/src/test/java/org/apache/curator/framework/recipes/leader/TestLeaderLatch.java
@@ -179,6 +179,63 @@ public void testUncreatedPathGetLeader() throws Exception {
         }
     }
 
+    // @see https://issues.apache.org/jira/browse/CURATOR-724
+    @Test
+    public void testGetChildrenHitsNoNode() throws Exception {
+        final String latchPath = "/testGetChildrenHitsNoNode";
+        final Timing2 timing = new Timing2();
+        final BlockingQueue<TestEvent> events0 = new LinkedBlockingQueue<>();
+        final BlockingQueue<TestEvent> events1 = new LinkedBlockingQueue<>();
+
+        final List<Closeable> closeableResources = new ArrayList<>();
+        try {
+            final String id0 = "id0";
+            final CuratorFramework client0 = createAndStartClient(server.getConnectString(), timing, id0, null);
+            closeableResources.add(client0);
+            final LeaderLatch latch0 = createAndStartLeaderLatch(client0, latchPath, id0, events0);
+            closeableResources.add(latch0);
+
+            assertThat(events0.poll(timing.forWaiting().milliseconds(), TimeUnit.MILLISECONDS))
+                    .isNotNull()
+                    .isEqualTo(new TestEvent(id0, TestEventType.GAINED_LEADERSHIP));
+
+            final String id1 = "id1";
+            final CuratorFramework client1 = createAndStartClient(server.getConnectString(), timing, id1, null);
+            closeableResources.add(client1);
+            final LeaderLatch latch1 = createAndStartLeaderLatch(client1, latchPath, id1, events1);
+            closeableResources.add(latch1);
+
+            // wait for the non-leading LeaderLatch (i.e. latch1) instance to be done with its creation
+            // this call is time-consuming but necessary because we don't have a handle to detect the end of the reset
+            // call
+            timing.forWaiting().sleepABit();
+
+            assertTrue(latch0.hasLeadership());
+            assertFalse(latch1.hasLeadership());
+
+            // ensure we can observe the leadership transferred to latch1
+            latch0.debugHandleReconnectedLatch = new CountDownLatch(1);
+
+            // scale to zero - recreate the cluster
+            final int port = server.getPort();
+            server.close();
+            server = new TestingServer(port, true);
+
+            assertThat(events1.poll(timing.forWaiting().milliseconds(), TimeUnit.MILLISECONDS))
+                    .isNotNull()
+                    .isEqualTo(new TestEvent(id1, TestEventType.GAINED_LEADERSHIP));
+
+            latch0.debugHandleReconnectedLatch.countDown();
+            assertThat(events0.poll(timing.forWaiting().milliseconds(), TimeUnit.MILLISECONDS))
+                    .isNotNull()
+                    .isEqualTo(new TestEvent(id0, TestEventType.LOST_LEADERSHIP));
+        } finally {
+            // reverse is necessary for closing the LeaderLatch instances before closing the corresponding client
+            Collections.reverse(closeableResources);
+            closeableResources.forEach(CloseableUtils::closeQuietly);
+        }
+    }
+
     @Test
     public void testWatchedNodeDeletedOnReconnect() throws Exception {
         final String latchPath = "/foo/bar";