fix: AnnotationEnhancer chain silently discards all modifications

[lossend]

Fixes #776

Problem

In RocketMQMessageListenerBeanPostProcessor.buildEnhancer(), the lambda accumulates
enhanced annotation attributes into newAttrs across all registered AnnotationEnhancer
beans, but then returns the original attrs instead of newAttrs.

This means every AnnotationEnhancer bean is silently a no-op — its attribute
modifications are computed but thrown away.

Fix

Return newAttrs instead of attrs.

// before
return attrs;

// after
return newAttrs;

Root Cause

buildEnhancer() (line 178–184):

this.enhancer = (attrs, element) -> {
    Map<String, Object> newAttrs = attrs;
    for (AnnotationEnhancer enh : enhancers) {
        newAttrs = enh.apply(newAttrs, element);
    }
    return attrs;   // BUG: should be newAttrs
};

Impact

Any application that relies on AnnotationEnhancer to dynamically override @RocketMQMessageListener attributes (e.g. injecting topic/group from environment properties) will find their customizations have no effect.

[RockteMQ-AI]

PR Review for #775: fix: AnnotationEnhancer chain silently discards all modifications

Summary

This PR modifies 1 file(s) with +1/-1 lines changed.

Changed Files

• rocketmq-v5-client-spring-boot/src/main/java/org/apache/rocketmq/client/annotation/RocketMQMessageListenerBeanPostProcessor.java

Observations

• PR author: @lossend
• Diff size: 897 characters
• 2 additions, 2 deletions in diff

Next Steps

A detailed code-level review requires the code engine. This is a structural overview only.
Please verify correctness, thread safety, and backward compatibility manually.

[RockteMQ-AI]

Summary

Clear bug fix: the buildEnhancer() lambda was returning the original attrs instead of the enhanced newAttrs, silently discarding all AnnotationEnhancer modifications. One-line fix that corrects the return value.

LGTM.

---

Automated review by github-manager-bot

[RockteMQ-AI]

Summary

This is a clear one-line bug fix: the AnnotationEnhancer chain lambda accumulates modifications into newAttrs but then returns the original attrs, silently discarding all enhancer modifications.

Analysis:

• The bug is in buildEnhancer() at line 183: return attrs; should be return newAttrs;
• The fix is correct and minimal — exactly one line changed
• No side effects: newAttrs is initialized from attrs and only modified by the enhancer chain
• This is a real bug that makes AnnotationEnhancer beans completely non-functional

LGTM. Good catch on a subtle but impactful bug.