[FLINK-21302][table-planner-blink] Fix NPE when use row_number() in over agg

[beyond1920]

What is the purpose of the change

Fix NPE when use row_number() in over agg.

Brief change log

Minor update in DeclarativeAggCodeGen to take aggregate without parameters into consideration.

Verifying this change

ITCase

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
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• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn/Mesos, 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

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Last check on commit 72a1f4b (Fri May 28 09:13:36 UTC 2021)

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• 72a1f4b Azure: SUCCESS

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[godfreyhe]

Thanks for the contribution @beyond1920 , It's better we make sure that the argIndexes is not null when AggregateInfo is created. That we can safely use the argIndexes anywhere.

[beyond1920]

@godfreyhe Thanks for the review. I've addressed.

[beyond1920]

@flinkbot run azure

[godfreyhe]

I think we need only make sure the argIndexes is not null when calling transformToAggregateInfo method. if that, there is only one place that needs to be changed.

[beyond1920]

@flinkbot run azure

[godfreyhe]

LGTM

[JingsongLi]

No sort here, this case is unstable.