Fix tag log append EOF handling

Author: Caideyipi

iotdb-core/datanode/src/main/java/org/apache/iotdb/db/schemaengine/schemaregion/tag/TagLogFile.java

@@ -147,6 +147,9 @@ private List<Long> parseOffsetList(long position) throws IOException {
     blockOffset.add(position);
     // Read the first block
     ByteBuffer byteBuffer = ByteBuffer.allocate(MAX_LENGTH);
+    if (position == fileChannel.size()) {
+      return blockOffset;
+    }
     IOUtils.readFully(fileChannel, byteBuffer, position);
     byteBuffer.flip();
     if (byteBuffer.limit() > 0) { // This indicates that there is data at this position

iotdb-core/datanode/src/test/java/org/apache/iotdb/db/schemaengine/schemaregion/tag/TagLogFileTest.java

@@ -0,0 +1,57 @@
+/*
+ * 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.iotdb.db.schemaengine.schemaregion.tag;
+
+import org.apache.tsfile.external.commons.io.FileUtils;
+import org.apache.tsfile.utils.Pair;
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.io.File;
+import java.nio.file.Files;
+import java.util.Collections;
+import java.util.Map;
+
+public class TagLogFileTest {
+
+  private File tempDir;
+
+  @After
+  public void tearDown() throws Exception {
+    if (tempDir != null) {
+      FileUtils.deleteDirectory(tempDir);
+    }
+  }
+
+  @Test
+  public void writeAppendsFirstRecordWithoutReadingPastFileEnd() throws Exception {
+    tempDir = Files.createTempDirectory("tag-log-file").toFile();
+    Map<String, String> tags = Collections.singletonMap("tag", "value");
+    Map<String, String> attributes = Collections.singletonMap("attr", "value");
+
+    try (TagLogFile tagLogFile = new TagLogFile(tempDir.getAbsolutePath(), "tag.log")) {
+      long offset = tagLogFile.write(tags, attributes);
+      Pair<Map<String, String>, Map<String, String>> result = tagLogFile.read(offset);
+
+      Assert.assertEquals(tags, result.left);
+      Assert.assertEquals(attributes, result.right);
+    }
+  }
+}