[ISSUE #4226] Message length exceeds the maximum length when sendback

[ni-ze]

Make consistent semantics of maxMessageSize, refers to the message body size.

In current version, maxMessageSize refers to message total length not only include message body but also include others fields, such as magic code, queueId, body crc, properties etc.

If we make length limit base on message body, we can get consistent semantics of maxMessageSize easily.

[codecov-commenter]

Codecov Report

Merging #4338 (085ddee) into develop (84fb5e1) will decrease coverage by 0.05%.
The diff coverage is 81.91%.

@@              Coverage Diff              @@
##             develop    #4338      +/-   ##
=============================================
- Coverage      48.20%   48.15%   -0.06%     
+ Complexity      5087     5074      -13     
=============================================
  Files            642      642              
  Lines          42762    42734      -28     
  Branches        5596     5590       -6     
=============================================
- Hits           20614    20578      -36     
- Misses         19637    19647      +10     
+ Partials        2511     2509       -2     

Impacted Files	Coverage Δ
...cketmq/broker/processor/ReplyMessageProcessor.java	55.11% <0.00%> (ø)
...he/rocketmq/client/producer/DefaultMQProducer.java	57.34% <ø> (ø)
...org/apache/rocketmq/store/DefaultMessageStore.java	55.56% <0.00%> (ø)
...pache/rocketmq/store/dledger/DLedgerCommitLog.java	76.43% <37.50%> (+0.36%)	⬆️
...etmq/broker/processor/EndTransactionProcessor.java	51.40% <50.00%> (ø)
...ache/rocketmq/store/config/MessageStoreConfig.java	61.72% <66.66%> (ø)
...main/java/org/apache/rocketmq/store/CommitLog.java	75.23% <90.90%> (+0.14%)	⬆️
...ocketmq/broker/processor/SendMessageProcessor.java	39.79% <100.00%> (ø)
...rg/apache/rocketmq/common/stats/StatsSnapshot.java	84.61% <0.00%> (-15.39%)	⬇️
.../apache/rocketmq/common/stats/MomentStatsItem.java	38.09% <0.00%> (-9.53%)	⬇️
... and 15 more

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[coveralls]

Coverage increased (+0.2%) to 52.129% when pulling 085ddee on ni-ze:messageLength-2 into 51cf962 on apache:develop.

[coveralls]

Coverage increased (+0.07%) to 52.047% when pulling 01e7d85 on ni-ze:messageLength-2 into 51cf962 on apache:develop.

There may be other compatibility issues, especially in MessageExtEncoder class

[dongeforever]

The code seems OK.

And it is better to add some tests, Sending a message with the body size equal to the maxMessageSize should succeed.

[ni-ze]

sure, I will add a unit test.