Missing features / bugs with Protobuf schema parser

I was running some tests on canonicalizing Protobuf schemas and found the following issues. The issues are mostly with the way FileDescriptorUtils parses the FileDescriptorProto into Proto schema and vice-versa. I baselined the results against the original Proto schema.

Original Protobuf schema: link

Expected Original FileDescriptorProto: link

FileDescriptorProto from parsing above Protobuf schema using below code: link

Code

FileDescriptorUtils.protoFileToFileDescriptor(...)

FileDescriptorProto from parsing schema generated by FileDescritptorUtils: link Code

FileDescriptorUtils.fileDescriptorToProtoFile(...).toSchema()

Summary of discrepancies

Feature	Syntax	Schema Text to FileDescriptorProto	FileDescriptorProto to Schema Text	Correct value
Internal references	Proto 2 / Proto 3	typeName is incorrect and type is missing	type is missing	type: TYPE_ENUMtype_name: “.foo.bar.AddressType”
json_name option	Proto 2 / Proto 3	Not present	Not present	json_name: “Address_Street”
deprecated option	Proto 2 / Proto 3	Not present	Not present	options { deprecated: true }
groups (deprecated feature)	Proto 2 / Proto 3 (deprecated)	Not present	Present but type is missing	Should be present with type = GROUP
Maps	Proto 2 / Proto3	Label is missing, name is not captialized	type is missing	Refer here
Reserved range Id	Proto 2 / Proto 3	Reserved ranges are present but end values are incorrect	Reserved ranges are missing	Refer here
Extension ranges	Proto 2 / Proto 3 (deprecated)	Not present	Not present	extension_range {start: 100end: 121}
Extensions	Proto 2 / Proto 3 (deprecated)	Not present	Not present	extension {name: "isPremium"extendee: ".foo.bar.Customer"number: 101label: LABEL_OPTIONALtype: TYPE_BOOL}
Nested references	Proto 2 / Proto 3	Incorrect type name and missing type	type and label is missing	field {name: "value"number: 2label: LABEL_OPTIONALtype: TYPE_MESSAGEtype_name: “.foo.bar.Address.Country”}
One Of	Proto 2 / Proto 3	Correctly interpreted but should be after required fields	Correctly interpreted but should be after required fields	Refer
Name property	Proto 2 / Proto 3	Incorrect as it’s not known	Incorrect as it’s not known
Syntax property	Proto 2 / Proto 3 / Empty	Empty is not interpreted correctly	Empty is not interpreted correctly	Empty shouldn’t be interpreted.
Services	Proto 2 / Proto 3	Not present	Not present	service {name: "AddressService"method {name: "Search"input_type: ".foo.bar.Customer"output_type: “.foo.bar.Address”}}

Questions

1. Are you aware of these discrepancies and working on fixing them?
2. Do you see any concerns with making these parsers as close as possible to outputs generated by standard Protobuf library?
3. I am willing to contribute to fix some of these discrepancies. Do you have any suggestions on how to take this forward?

[blacktooth]

Thanks a lot for being open and supporting us in contributing these bug fixes. We have contributed all the changes. This issue can be resolved. Thanks again!

[EricWittmann]

Thank you for the contribution!