issue

Author: TaiJuWu

storage/src/test/java/org/apache/kafka/storage/internals/log/UnifiedLogTest.java

@@ -465,7 +465,7 @@ public void testDeleteOldSegments() throws IOException {
                 .withRetentionMs(999)
                 .build();
         log = createLog(logDir, logConfig);
-        // avoid close after test because it is closed in this test
+        // Avoid close after test because it is deleted in this test. See line 517.
         logsToClose.remove(log);
 
         // append some messages to create some segments
@@ -513,6 +513,9 @@ public void testDeleteOldSegments() throws IOException {
             log.appendAsLeader(records.get(), 0);
         }
 
+        // bug? Due to log.delete() we can't  close the unifiedLog
+        // because we delete log and at that moment, and then the memory map is closed.
+        // So it will throw KafkaStorageException when closing.
         log.delete();
         assertEquals(0, log.numberOfSegments(), "The number of segments should be 0");
         assertEquals(0, log.deleteOldSegments(), "The number of deleted segments should be zero.");