From c2d48672a66ce0438f57c9bce6fadedf60ae8187 Mon Sep 17 00:00:00 2001
From: yuluo-yx <yuluo08290126@gmail.com>
Date: Sat, 8 Aug 2026 18:04:51 +0800
Subject: [PATCH] [ISSUE #10863] fix(common): persist empty checkpoints

---
 .../rocketmq/common/utils/CheckpointFile.java | 11 +--
 .../common/utils/CheckpointFileTest.java      | 70 +++++++++++++++++++
 2 files changed, 73 insertions(+), 8 deletions(-)
 create mode 100644 common/src/test/java/org/apache/rocketmq/common/utils/CheckpointFileTest.java

diff --git a/common/src/main/java/org/apache/rocketmq/common/utils/CheckpointFile.java b/common/src/main/java/org/apache/rocketmq/common/utils/CheckpointFile.java
index 1cb85d05eee..e1e45692506 100644
--- a/common/src/main/java/org/apache/rocketmq/common/utils/CheckpointFile.java
+++ b/common/src/main/java/org/apache/rocketmq/common/utils/CheckpointFile.java
@@ -24,7 +24,6 @@
 import java.nio.file.Files;
 import java.util.ArrayList;
 import java.util.List;
-import org.apache.commons.collections.CollectionUtils;
 import org.apache.rocketmq.common.MixAll;
 import org.apache.rocketmq.common.UtilAll;
 
@@ -75,9 +74,6 @@ public String getBackFilePath() {
      * Write entries to file
      */
     public void write(final List<T> entries) throws IOException {
-        if (entries.isEmpty()) {
-            return;
-        }
         synchronized (this) {
             StringBuilder entryContent = new StringBuilder();
             for (T entry : entries) {
@@ -143,11 +139,10 @@ private List<T> read(String filePath) throws IOException {
      */
     public List<T> read() throws IOException {
         try {
-            List<T> result = this.read(this.filePath);
-            if (CollectionUtils.isEmpty(result)) {
-                result = this.read(this.getBackFilePath());
+            if (new File(this.filePath).exists()) {
+                return this.read(this.filePath);
             }
-            return result;
+            return this.read(this.getBackFilePath());
         } catch (IOException e) {
             return this.read(this.getBackFilePath());
         }
diff --git a/common/src/test/java/org/apache/rocketmq/common/utils/CheckpointFileTest.java b/common/src/test/java/org/apache/rocketmq/common/utils/CheckpointFileTest.java
new file mode 100644
index 00000000000..cb13c180efd
--- /dev/null
+++ b/common/src/test/java/org/apache/rocketmq/common/utils/CheckpointFileTest.java
@@ -0,0 +1,70 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.rocketmq.common.utils;
+
+import java.io.File;
+import java.nio.file.Files;
+import java.util.Arrays;
+import java.util.Collections;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class CheckpointFileTest {
+
+    @Rule
+    public TemporaryFolder temporaryFolder = new TemporaryFolder();
+
+    @Test
+    public void writeEmptyEntriesClearsPreviousCheckpoint() throws Exception {
+        File file = new File(temporaryFolder.getRoot(), "checkpoint");
+        CheckpointFile<Integer> checkpointFile = newCheckpointFile(file);
+        checkpointFile.write(Arrays.asList(1, 2));
+
+        checkpointFile.write(Collections.emptyList());
+
+        assertThat(checkpointFile.read()).isEmpty();
+        assertThat(Files.readAllLines(file.toPath()).get(0)).isEqualTo("0");
+    }
+
+    @Test
+    public void readFallsBackToBackupWhenPrimaryIsCorrupt() throws Exception {
+        File file = new File(temporaryFolder.getRoot(), "checkpoint");
+        CheckpointFile<Integer> checkpointFile = newCheckpointFile(file);
+        checkpointFile.write(Collections.singletonList(1));
+        checkpointFile.write(Collections.singletonList(2));
+        Files.write(file.toPath(), Arrays.asList("1", "1", "2"));
+
+        assertThat(checkpointFile.read()).containsExactly(1);
+    }
+
+    private CheckpointFile<Integer> newCheckpointFile(File file) {
+        return new CheckpointFile<>(file.getAbsolutePath(), new CheckpointFile.CheckpointSerializer<Integer>() {
+            @Override
+            public String toLine(Integer entry) {
+                return entry.toString();
+            }
+
+            @Override
+            public Integer fromLine(String line) {
+                return Integer.valueOf(line);
+            }
+        });
+    }
+}