Client generation error when property names differ only by underscore prefix / suffix

Originally predicted in https://github.com/openapi-generators/openapi-python-client/issues/383#issuecomment-830839559

Since re.findall(rf"[^{DELIMITERS}]+", value) trims prefix and suffix _ characters while generating python property identifiers, 2+ schema properties on a single model that differ only by such underscores causes CLI generate and update commands to fail.

Given it would be problematic to carry through those untrimmed identifiers due to the semantic meaning of prefix and suffix _ on identifiers in python, it makes sense to have a fallback value to use like a title property or a configurable prefix.

Resulting error:

$ openapi-python-client generate --path schema-underscore-collision.yaml --fail-on-warning

Generating schema-underscore-collision-client
Error(s) encountered while generating, client was not created

black failed

reformatted schema_underscore_collision_client/api/__init__.py
reformatted schema_underscore_collision_client/__init__.py
reformatted schema_underscore_collision_client/types.py
error: cannot format schema_underscore_collision_client/models/get_response_200.py: cannot use --safe with this file; failed to parse source file AST: keyword argument repeated (<unknown>, line 55)
This could be caused by running Black with an older Python version that does not support new syntax used in your source file.
reformatted schema_underscore_collision_client/client.py
reformatted schema_underscore_collision_client/api/default/get.py

Oh no! 💥 💔 💥
5 files reformatted, 2 files left unchanged, 1 file failed to reformat.

Using an example schema-underscore-collision.yaml:

openapi: 3.0.2
info:
  title: schema-underscore-collision 
  version: 1.0.0
paths:
  /:
    get:
      description: 
      responses:
        '200':
          description: test
          content:
            application/json:
              schema:
                type: object
                properties:
                  _a: {}
                  a: {}
                  a_: {}

The problematic schema_underscore_collision_client/models/get_response_200.py file, reported error is in the from_dict method but to_dict also suffers from the ambiguity:

from typing import Any, BinaryIO, Dict, List, Optional, TextIO, Tuple, Type, TypeVar, Union

import attr

from ..types import UNSET, Unset

T = TypeVar("T", bound="GetResponse200")

@attr.s(auto_attribs=True)
class GetResponse200:
    """
    Attributes:
        a (Union[Unset, Any]):
        a (Union[Unset, Any]):
        a (Union[Unset, Any]):
    """

    a: Union[Unset, Any] = UNSET
    a: Union[Unset, Any] = UNSET
    a: Union[Unset, Any] = UNSET
    additional_properties: Dict[str, Any] = attr.ib(init=False, factory=dict)


    def to_dict(self) -> Dict[str, Any]:
        a = self.a
        a = self.a
        a = self.a

        field_dict: Dict[str, Any] = {}
        field_dict.update(self.additional_properties)
        field_dict.update({
        })
        if a is not UNSET:
            field_dict["_a"] = a
        if a is not UNSET:
            field_dict["a"] = a
        if a is not UNSET:
            field_dict["a_"] = a

        return field_dict



    @classmethod
    def from_dict(cls: Type[T], src_dict: Dict[str, Any]) -> T:
        d = src_dict.copy()
        a = d.pop("_a", UNSET)

        a = d.pop("a", UNSET)

        a = d.pop("a_", UNSET)

        get_response_200 = cls(
            a=a,
            a=a,
            a=a,
        )

        get_response_200.additional_properties = d
        return get_response_200

    @property
    def additional_keys(self) -> List[str]:
        return list(self.additional_properties.keys())

    def __getitem__(self, key: str) -> Any:
        return self.additional_properties[key]

    def __setitem__(self, key: str, value: Any) -> None:
        self.additional_properties[key] = value

    def __delitem__(self, key: str) -> None:
        del self.additional_properties[key]

    def __contains__(self, key: str) -> bool:
        return key in self.additional_properties

Versions

• Python: 3.7.12
• openapi-python-client: 0.11.1

Start with openapi_python_client/utils.py around the linked findall call, then trace the CLI generate and update entry points. Reproduce the collision with schema-underscore-collision.yaml and inspect the generated model's to_dict and from_dict methods. Done means distinct valid Python identifiers are generated for properties such as a, a, and a, without duplicate fields or keyword arguments.