Summary

This is a reproducer of the bug here: #1648 (comment)

There are 3 commits in this PR. If you checkout the code in the second commit you will see the panic happening in the TestArrayTupleNullableFieldPanic test.

If you checkout the 3rd commit (tip of the branch) the test is fixed.

Notice how the deserialization into a nullable field that is inside a tuple causes a panic.

There are 2 tests - one using nullable field (which fails with the panic) and one which succeeds without using nullable.

Notice that the existing method scanMap and scanSlice already properly handle nil cases it was only missing in this scanStruct.

Checklist

Delete items not relevant to your PR:

• [ x] Unit and integration tests covering the common scenarios were added
• [ x] A human-readable description of the changes was provided to include in CHANGELOG
• [ x] For significant changes, documentation in https://github.com/ClickHouse/clickhouse-docs was updated with further explanations or tutorials