[C++] ExecBatch support for ChunkedArray values

[asfimport]

Currently, ExecBatch does not handle chunked arrays when printing or slicing. The code assumes that if a value is not a scalar then it is an array, and so will fail on chunked array values.

Reporter: Yaron Gvili / @rtpsw
Assignee: Yaron Gvili / @rtpsw

PRs and other links:

• GitHub Pull Request #14348

_{Note: This issue was originally created as ARROW-17965. Please see the migration documentation for further details.}

[asfimport]

David Li / @lidavidm:
Without context, this seems odd; why wouldn't the ChunkedArray itself be split and fed into an ExecPlan as individual batches?

[asfimport]

Yaron Gvili / @rtpsw:
Not sure how much context you are asking for. I bumped into this when working on ordered aggregation. The test cases I worked out for this involved chunked arrays (but not an ExecPlan) that triggered the described failure that led to this issue.

I suppose it is possible to split to multiple ExecBatch instances, but I think this is not convenient for the user and potentially less efficient, e.g., in the context of streaming it is more efficient to consume a large ExecBatch with a chunked array than to consume multiple smaller ExecBatch instances with the same data.

I believe the proposed code is simple enough to warrant a review. Let me know your thoughts.

[asfimport]

David Li / @lidavidm:
Issue resolved by pull request 14348
#14348