[FLINK-36209] Remove redundant operations in the initialization of KafkaSourceEnumState

[xiaochen-zhou]

What is the purpose of the change

In certain methods, such as the DynamicKafkaSourceEnumerator#onHandleSubscribedStreamsFetch() method, partitions are divided into assignedPartitions and unassignedInitialPartitions before being passed as parameters to the KafkaSourceEnumState constructor. However, within the constructor, these assignedPartitions and unassignedInitialPartitions are recombined into partitions, leading to unnecessary operations and reduced performance. By optimizing the code to pass partitions directly as a parameter when initializing KafkaSourceEnumState, we can eliminate redundant operations and enhance performance.

Brief change log

Verifying this change

• This change is a trivial rework / code cleanup without any test coverage.
• Does this pull request potentially affect one of the following parts:
• Dependencies (does it add or upgrade a dependency): (no)
• The public API, i.e., is any changed class annotated with @public(Evolving): (no)
• The serializers: (no)
• The runtime per-record code paths (performance sensitive): (no)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: (no)
• The S3 file system connector: (no)

Documentation

• Does this pull request introduce a new feature? no)
• If yes, how is the feature documented? (not applicable)

[boring-cyborg]

Thanks for opening this pull request! Please check out our contributing guidelines. (https://flink.apache.org/contributing/how-to-contribute.html)

[xiaochen-zhou]

Friendly ping, do you have time to take a look @AHeise 🙏 ?

[AHeise]

Thank you very much for your contribution. The change almost LGTM with one little change. I'm running CI.

[AHeise]

I'd rename to deserializeAssignedPartitions and inline status. I don't see it being used with UNASSIGNED.

[xiaochen-zhou]

I'd rename to deserializeAssignedPartitions and inline status. I don't see it being used with UNASSIGNED.

Thank you for your careful review, I changed to them.

[xiaochen-zhou]

I'd rename to deserializeAssignedPartitions and inline status. I don't see it being used with UNASSIGNED.

done.

[xiaochen-zhou]

Friendly ping, passed ci. If you have time, pls help to review it again. thanks a lot. @AHeise

[AHeise]

LGTM. Thank you very much for your contribution. Will merge now.