[jira] [Created] (KAFKA-15136) The inspection of field allowAutoTopicCreation field in MetadataRequest is unreasonable

["Xiaobing Fang (Jira)" <ji...@apache.org>]

Xiaobing Fang created KAFKA-15136:
-------------------------------------

             Summary: The inspection of field allowAutoTopicCreation field in MetadataRequest is unreasonable
                 Key: KAFKA-15136
                 URL: https://issues.apache.org/jira/browse/KAFKA-15136
             Project: Kafka
          Issue Type: Improvement
          Components: clients
            Reporter: Xiaobing Fang


```java

if (!data.allowAutoTopicCreation() && version < 4)
throw new UnsupportedVersionException("MetadataRequest versions older than 4 don't support the " +
"allowAutoTopicCreation field");

```

Background:
Based on my understanding, the code in MetadataRequest is intended to ignore the allowAutoTopicCreation field when version≤4. However, if kafka server is configured with "auto.create.topics.enable"=false and the client sets allowAutoTopicCreation=false, UnsupportedVersionExceptionwill be thrown, which is not expected.

Issues:
 # `KafkaAdminClient#handleDescribeTopicsByNames()` throws an exception when sending MetadataRequest to a lower version server, making it unusable.
 # MetadataRequestTest avoids this issue by setting `allowAutoTopicCreation=true` in tests for version≤4, but this is not reasonable. And the comments in [testAutoTopicCreation|https://github.com/apache/kafka/blob/1f4cbc5d53259031123b6e9e6bb9a5bbe1e084e8/core/src/test/scala/unit/kafka/server/MetadataRequestTest.scala#L146] may also be problematic.

Solution:  
 # Remove the checking code in MetadataRequest.
 # Add a field `hasSetAllowAutoTopicCreation` in MetadataRequest. Only throw an exception when `version≤4` and `hasSetAllowAutoTopicCreation=true`, without considering the value of allowAutoTopicCreation field.

 

If there is indeed an issue, I can work on fixing it. Looking forward to your reply.



--
This message was sent by Atlassian Jira
(v8.20.10#820010)