Unable to access custom field extension options in protobuf Descriptor

[dravula1]

Hi, I am working on validating protobuf messages using buf-protovalidate, which requires us to have the custom buf validate field options support in the descriptor.

So far, we are able to pull the schema from confluent schema registry to the ParsedSchema object, but when trying to fetch its descriptor type, it is cutting off the FieldOptions for the fields.

Even with FieldOptions extension,

extend google.protobuf.FieldOptions { optional FieldConstraints field = 1159; }

It seem to be a similar issue as protocolbuffers/protobuf#12049. Can someone help with a possible workaround in java.

So far I have been trying with no luck, to manually build field descriptor proto with field options. Atleast a sample on how to build FieldOptions with extensions (using OptionElement object) would help as well. Thank you in advance!