Parquet.ParquetException: 'NewField' does not exist in this file (Schema evolution with ParquetConvert.Deserialize)

Version: 3.9.0

Runtime Version: .Net Core v 2.2

OS: Windows

Expected behavior

I am having an issue with schema evolution. Added a new field in my type and it is not able to deserialize now. Can we mark a field optional somhow?

Actual behavior

Parquet.ParquetException: ‘NewField’ does not exist in this file

Steps to reproduce the behavior

1. Serialize a collection of certain type.
2. Add a field to the type.
3. Deserialize using ParquentConvert.Deserialize<T>(“…”);

Code snippet reproducing the behavior

using (Stream fileStream = System.IO.File.OpenRead(“C:\temp\parquet\data.parquet”)) { positions = ParquetConvert.Deserialize<MyType>(fileStream); }

//here

[aloneguid]

Unlikely as I don’t need it personally. Although PRs are always welcome.

[VolodymyrSenchak]

I would also love to have such an attribute like [ParquetOptional].

By the way, just to mimic JSON deserialization behavior - I think that not throwing an error and just applying default value if the field which is declared in class does not exist in the file - would be much more expected behavior.

Or are there any limitations to doing that?