[Bug] MessageQueue.compareTo overflows for extreme queue IDs

[yuluo-yx]

Before Creating the Bug Report

• I found a bug, not just a question.
• I searched open GitHub Issues and pull requests and found no duplicate.
• I confirmed that this bug belongs to Apache RocketMQ.

Runtime platform environment

macOS (Darwin), reproduced with an isolated local unit test.

RocketMQ version

Branch: develop
Git commit: fd0c959

JDK Version

Zulu OpenJDK 8 (8.94.0.17)

Describe the Bug

MessageQueue.compareTo compares queue IDs by subtraction. For sufficiently distant int values, subtraction overflows and reverses the comparison sign, violating the Comparable contract.

Steps to Reproduce

1. Create two MessageQueue objects with the same topic and broker.
2. Use queue IDs Integer.MIN_VALUE and Integer.MAX_VALUE.
3. Compare them in both directions.
4. Observe that subtraction can produce the wrong sign.

What Did You Expect to See?

Queue IDs should be ordered according to their numeric value for the full int range.

What Did You See Instead?

Integer overflow can make a smaller queue ID compare as greater than a larger queue ID.

Additional Context

The behavior is reproducible without external services in MessageQueueTest.

[RockteMQ-AI]

Issue Evaluation

Category: type/bug | Status: Confirmed

Root Cause: MessageQueue.compareTo compares queue IDs by subtraction (this.queueId - other.queueId). For extreme int values (e.g., Integer.MIN_VALUE and Integer.MAX_VALUE), the subtraction overflows and reverses the comparison sign, violating the Comparable contract.
Impact: Client-side message queue ordering — sorting operations on message queues with extreme queue IDs may produce incorrect ordering, affecting load balancing and consumption.
Severity: low (queue IDs are typically small positive values in practice, but the contract violation is real)

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Automated evaluation by github-manager-bot