PARQUET-2299: Use `true` instead of `1` as default value for `is_compressed` bool field

[mbrobbel]

I noticed that the default value for the optional boolean is_compressed field of the DataPageHeaderV2 struct has a default value of 1. According to the Thrift docs a boolean value is either true or false.

This currently works because the Apache Thrift compiler internally handles bools as ints:

• https://github.com/apache/thrift/blob/3880a09565a9a1dad028b3679746eafac268c819/compiler/cpp/src/thrift/thriftl.ll#L208-L209
• https://github.com/apache/thrift/blob/3880a09565a9a1dad028b3679746eafac268c819/compiler/cpp/src/thrift/main.cc#L748

It may however not work with other Thrift compilers that are more strict about this.

Based on the docs and a test in the Thrift repository it seems that using true here is the correct way of defining a default for an optional bool field.

[wgtmac]

Thanks! Would you mind creating a JIRA for this?

[wgtmac]

Thanks @mbrobbel! I have also added you as a contributor to the Apache Parquet JIRA project and assigned this to you.