MINOR [Go] Add nested struct test for pqarrow

[candiduslynx]

@zeroshade I've found a disturbing behavior with structs (namely, nested ones) in pqarrow.

This blocks cloudquery/filetypes#172

Could you please take a look?

[github-actions]

Thanks for opening a pull request!

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Then could you also rename the pull request title in the following format?

GH-${GITHUB_ISSUE_ID}: [${COMPONENT}] ${SUMMARY}

or

MINOR: [${COMPONENT}] ${SUMMARY}

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PARQUET-${JIRA_ISSUE_ID}: [${COMPONENT}] ${SUMMARY}

See also:

• Other pull requests
• Contribution Guidelines - How to contribute patches

[candiduslynx]

@zeroshade I found an issue with the test & it should now pass, but I'm really confused about array.NewStructData behavior in conjunction with pqarrow.
Could you please take a look at the code in cloudquery/filetypes#172?
Specifically, the issue I see is that the offsets/null bitmaps for the nested field are propagated strangely.
It panics while trying to create Struct array from data, so I don't know where to look.

[candiduslynx]

I guess the issue can be connected to https://github.com/apache/arrow/blob/main/go/parquet/pqarrow/encode_arrow_test.go#L1040-L1042

// current impl of ArrayEquals for structs doesn't correctly handle nulls in the parent
// with a non-nullable child when comparing. Since after the round trip, the data in the
// child will have the nulls, not the original data.

[candiduslynx]

I'm closing this for now, however, it would've been nice to be able to use array.NewStructData on the read values