Support for Protobuf Descriptors

[terrypireaux]

Is your feature request related to a problem? Please describe.
The library does not currently support Protobuf Descriptors

Describe the solution you'd like
Support for protobuf descriptors as works in buf.build/protocolbuffers/python plugin

Describe alternatives you've considered
There is no clean alternative that is scalable, post processing the generated p2p files is cumbersome.

[so1n]

@terrypireaux Thanks for your feedback, please provide sample code to help me solve the problem faster

[terrypireaux]

Example Proto

syntax = "proto3";
package example.model.common;

import "google/protobuf/descriptor.proto";

// Define custom options for categorizing enum values
extend google.protobuf.EnumValueOptions {
  bool is_premium = 60000;
  string category = 60001;
}

// Example enum representing product types
enum ProductType {
  PRODUCT_UNSPECIFIED = 0;
  PRODUCT_BASIC = 1 [(is_premium) = false, (category) = "standard"];
  PRODUCT_PRO = 2 [(is_premium) = true, (category) = "premium"];
  PRODUCT_ULTIMATE = 3 [(is_premium) = true, (category) = "premium"];
}

Example output from basic python plugin

// -*- coding: utf-8 -*-
// Generated by the protocol buffer compiler.  DO NOT EDIT!
// source: example/model/common/categories.proto
// Protobuf Python Version: 5.26.0
"""Generated protocol buffer code."""
from google.protobuf import descriptor as _descriptor
from google.protobuf import descriptor_pool as _descriptor_pool
from google.protobuf import symbol_database as _symbol_database
from google.protobuf.internal import builder as _builder
// @@protoc_insertion_point(imports)

_sym_db = _symbol_database.Default()


from google.protobuf import descriptor_pb2 as google_dot_protobuf_dot_descriptor__pb2


DESCRIPTOR = _descriptor_pool.Default().AddSerializedFile(b'\example/model/common/categories.proto\x12 example.model.common\x1a google/protobuf/descriptor.proto*\x94\x01\n\x0bProductType\x12\x17\n\x13PRODUCT_UNSPECIFIED\x10\x00\x12#\n\rPRODUCT_BASIC\x10\x01\x1a\x10\x80\xa6\x1d\x00\x8a\xa6\x1d\x08standard\x12 \n\x0bPRODUCT_PRO\x10\x02\x1a\x0f\x80\xa6\x1d\x01\x8a\xa6\x1d\x07premium\x12%\n\x10PRODUCT_ULTIMATE\x10\x03\x1a\x0f\x80\xa6\x1d\x01\x8a\xa6\x1d\x07premium:B\n\nis_premium\x12!.google.protobuf.EnumValueOptions\x18\xe0\xd4\x03 \x01(\x08R\tisPremium:?\n\x08\x63\x61tegory\x12!.google.protobuf.EnumValueOptions\x18\xe1\xd4\x03 \x01(\tR\x08\x63\x61tegoryb\x06proto3')

_globals = globals()
_builder.BuildMessageAndEnumDescriptors(DESCRIPTOR, _globals)
_builder.BuildTopDescriptorsAndMessages(DESCRIPTOR, 'example.model.common.categories_pb2', _globals)
if not _descriptor._USE_C_DESCRIPTORS:
  DESCRIPTOR._loaded_options = None
  _globals['_PRODUCTTYPE'].values_by_name["PRODUCT_BASIC"]._loaded_options = None
  _globals['_PRODUCTTYPE'].values_by_name["PRODUCT_BASIC"]._serialized_options = b'\200\246\035\000\212\246\035\010standard'
  _globals['_PRODUCTTYPE'].values_by_name["PRODUCT_PRO"]._loaded_options = None
  _globals['_PRODUCTTYPE'].values_by_name["PRODUCT_PRO"]._serialized_options = b'\200\246\035\001\212\246\035\007premium'
  _globals['_PRODUCTTYPE'].values_by_name["PRODUCT_ULTIMATE"]._loaded_options = None
  _globals['_PRODUCTTYPE'].values_by_name["PRODUCT_ULTIMATE"]._serialized_options = b'\200\246\035\001\212\246\035\007premium'
  _globals['_PRODUCTTYPE']._serialized_start=122
  _globals['_PRODUCTTYPE']._serialized_end=270

Potential Pydantic

here is a rough example but basically need to just have the same options as the generic python

// -*- coding: utf-8 -*-
// Generated by protobuf_to_pydantic
// source: example/model/common/categories.proto
from enum import IntEnum
from typing import ClassVar, Dict, Any
from pydantic import BaseModel

class ProductType(IntEnum):
    """Example enum representing product types with descriptor metadata."""
    PRODUCT_UNSPECIFIED = 0
    PRODUCT_BASIC = 1
    PRODUCT_PRO = 2
    PRODUCT_ULTIMATE = 3
    
    // Access to the descriptor options through a class variable
    // This would be populated by protobuf-to-pydantic during code generation
    _descriptor_options: ClassVar[Dict[int, Dict[str, Any]]] = {
        // Value 0 has no custom options
        // Value 1 options from: b'\200\246\035\000\212\246\035\010standard'
        1: {"is_premium": False, "category": "standard"},
        // Value 2 options from: b'\200\246\035\001\212\246\035\007premium'
        2: {"is_premium": True, "category": "premium"},
        // Value 3 options from: b'\200\246\035\001\212\246\035\007premium'
        3: {"is_premium": True, "category": "premium"},
    }

Usage

A potential usage example

Pydantic

// Direct access to options via the class variable
options_basic = ProductType._descriptor_options[ProductType.PRODUCT_BASIC]