GH-48168: [C++][Parquet] Fix setting column-specific options when writing an encrypted Dataset

[adamreeve]

Rationale for this change

Fixes creation of writer properties when writing a Parquet Dataset with encryption, so that column-specific settings aren't lost.

What changes are included in this PR?

Changes the WriterProperties::Builder constructor that uses existing properties so that it also sets any column-specific settings.

Are these changes tested?

Yes.

Are there any user-facing changes?

Yes, this fixes a user-facing bug.

• GitHub Issue: [Parquet] Cannot enable statistics for specific fields when writing a dataset with encryption #48168

[wgtmac]

I just noticed that WriterProperties and WriterProperties::Builder use different forms to represent column properties. Is it possible to simplify this by using the same form?

[adamreeve]

I think the builder needs to work this way so that different column-specific properties can be changed as well as changing default column properties without the order of operations affecting the result. I don't think the WriterProperties can be changed to use the Builder's representation without breaking the API as ColumnProperties is part of the public API and returned as a reference:

arrow/cpp/src/parquet/properties.h

Line 911 in e6ad2c4

const ColumnProperties& column_properties(

[rok]

Looks good, strange we don't currently do this. Just a minor change request.

[conbench-apache-arrow]

After merging your PR, Conbench analyzed the 3 benchmarking runs that have been run so far on merge-commit 39c865e.

There were no benchmark performance regressions. 🎉

The full Conbench report has more details. It also includes information about 4 possible false positives for unstable benchmarks that are known to sometimes produce them.