Direct Get batch request returns messages before start time when exactly 1 message in stream

[scottf]

Behavior

Direct get batch with start_time returns message before start_time when there is exactly 1 message in the stream.

Server version

v2.11.0-dev (Head of main on 05-20-2025)

Steps to reproduce

1. create a new stream and publish exactly 1 message.
2. publish a direct get batch request with a time 10 seconds in the future, ensuring the time is well past the message time.
   {"batch":1,"start_time":"2024-11-05T13:31:29.144000000Z","next_by_subj":"testSubject"}
3. View the messages coming in on the subscription, you will receive the message 1, not a 404

[scottf]

I can reproduce this issue against Server. This code uses the Java Orbit DirectBatch library

String stream = "stream6032";
String subject = "subject6032";
try (Connection nc = Nats.connect(runner.getURI())) {
    JetStreamManagement jsm = nc.jetStreamManagement();
    JetStream js = jsm.jetStream();

    // 1. create a new stream.
    jsm.addStream(StreamConfiguration.builder()
        .name(stream)
        .subjects(subject)
        .allowDirect(true)
        .storageType(StorageType.Memory)
        .build());

    // 2. publish 1 message.
    js.publish(subject, ("Message 1").getBytes());

    // 3. get the messages directly to know its time
    MessageInfo mi = jsm.getMessage(stream, 1);
    System.out.println(mi);

    // 4. Use the direct batch context to make a batch request
    //    for a subject, and time after the last message
    DirectBatchContext db = new DirectBatchContext(nc, stream);

    System.out.println("\nWith 1 message in stream");
    ZonedDateTime futureTime = DateTimeUtils.gmtNow().plusSeconds(30);
    System.out.println("Message 1 Time: " + mi.getTime() + "\nFuture Time:  " + futureTime);

    MessageBatchGetRequest request = MessageBatchGetRequest.batch(subject, 1, futureTime);
    System.out.println("Request:\n    " + request);
    List<MessageInfo> list = db.fetchMessageBatch(request);
    list.forEach(m -> System.out.println("    " + m));

    // 5. publish another message
    js.publish(subject, ("Message 2").getBytes());

    System.out.println("\nWith 2 messages in stream");
    System.out.println("Message 1 Time: " + mi.getTime() + "\nFuture Time:  " + futureTime);

    // 6. Use the direct batch context to make a batch request
    //    for a subject, and time after the last message
    request = MessageBatchGetRequest.batch(subject, 1, futureTime);
    System.out.println("Request:\n    " + request);
    list = db.fetchMessageBatch(request);
    list.forEach(m -> System.out.println("    " + m));
}

Here is the output (manually formatted)

Direct Get MessageInfo for sequence 1 to show time:

{
  "seq": 1,
  "num_pending": -1,
  "stream": "stream6032",
  "subject": "subject6032",
  "time": "2025-05-21T12:37:31.245744800Z",
  "data_length": 9
}

With 1 message in stream:

Message 1 Time: 2025-05-21T12:37:31.245744800Z[GMT]
Future Time:    2025-05-21T12:38:01.262Z[GMT]
Request:
{"batch":1,"start_time":"2025-05-21T12:38:01.262000000Z","next_by_subj":"subject6032"}
Response
{
  "seq": 1,
  "last_seq": 0,
  "num_pending": 0,
  "stream": "stream6032",
  "subject": "subject6032",
  "time": "2025-05-21T12:37:31.245744800Z",
  "data_length": 9
}

With 2 messages in stream, identical times and identical request:

Response
{"status_code":404,"status_message":"Message Not Found"}