[BUG][python] Generator generating reserved word ("from")

[Lnk2past]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?

Description

I am attempting to use a spec that I have no control over (I cannot just change the spec). A "step" structure is implemented with from and to properties; however, when the structure is nested, the from keyword does not get escaped. This results in invalid Python code being produced.

Upon importing the models, I am instantly hit with a syntax error:

>>> import openapi_client.models
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.8/dist-packages/openapi_client/models/__init__.py", line 14, in <module>
    from openapi_client.model.my_response import MyResponse
  File "/usr/local/lib/python3.8/dist-packages/openapi_client/model/my_response.py", line 45
    def from() -> typing.Type['MyResponseData']:
        ^
SyntaxError: invalid syntax

The associated code looks like (shortened slightly for brevity):

class MyResponse(
    schemas.DictSchema
):
    """NOTE: This class is auto generated by OpenAPI Generator.
    Ref: https://openapi-generator.tech

    Do not edit the class manually.
    """


    class MetaOapg:
        required = {
            "from",
            "to",
        }
        
        class properties:
        
            @staticmethod
            def from() -> typing.Type['MyResponseData']:
                return MyResponseData
        
            @staticmethod
            def to() -> typing.Type['MyResponseData']:
                return MyResponseData
            __annotations__ = {
                "from": _from,
                "to": to,
            }
    
    to: 'MyResponseData'
    
    @typing.overload
    def __getitem__(self, name: typing_extensions.Literal["from"]) -> 'MyResponseData': ...
    
    @typing.overload
    def __getitem__(self, name: typing_extensions.Literal["to"]) -> 'MyResponseData': ...
    
    @typing.overload
    def __getitem__(self, name: str) -> schemas.UnsetAnyTypeSchema: ...
    
    def __getitem__(self, name: typing.Union[typing_extensions.Literal["from", "to", ], str]):
        # dict_instance[name] accessor
        return super().__getitem__(name)
    
    
    @typing.overload
    def get_item_oapg(self, name: typing_extensions.Literal["from"]) -> 'MyResponseData': ...
    
    @typing.overload
    def get_item_oapg(self, name: typing_extensions.Literal["to"]) -> 'MyResponseData': ...
    
    @typing.overload
    def get_item_oapg(self, name: str) -> typing.Union[schemas.UnsetAnyTypeSchema, schemas.Unset]: ...
    
    def get_item_oapg(self, name: typing.Union[typing_extensions.Literal["from", "to", ], str]):
        return super().get_item_oapg(name)
    

    def __new__(
        cls,
        *args: typing.Union[dict, frozendict.frozendict, ],
        to: 'MyResponseData',
        _configuration: typing.Optional[schemas.Configuration] = None,
        **kwargs: typing.Union[schemas.AnyTypeSchema, dict, frozendict.frozendict, str, date, datetime, uuid.UUID, int, float, decimal.Decimal, None, list, tuple, bytes],
    ) -> 'MyResponse':
        return super().__new__(
            cls,
            *args,
            to=to,
            _configuration=_configuration,
            **kwargs,
        )

I do not know what the entirety of this code should look like, but I do know that the specific code producing the syntax error should at least look like this:

            @staticmethod
            def _from() -> typing.Type['MyResponseData']:
                return MyResponseData

openapi-json-schema-generator version

master branch; this is not a regression as the issue was reported here (and it is still an issue): OpenAPITools/openapi-generator#7119

OpenAPI declaration file content or url

openapi: "3.0.0"
info:
  title: Sample
  version: "1.0.0"
paths:
  /test_one:
    get:
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/my_response"
components:
  schemas:
    my_response:
      type: object
      properties:
        from:
          $ref: "#/components/schemas/my_response_data"
        to:
          $ref: "#/components/schemas/my_response_data"
      required:
        - from
        - to
    my_response_data:
      type: object
      properties:
        data:
          type: string
        id:
          type: integer

Generation Details

java -jar modules/openapi-json-schema-generator-cli/target/openapi-json-schema-generator-cli.jar generate \
    -i /TEST.yaml \
    -g python \
    -t modules/openapi-json-schema-generator/src/main/resources/python \
    -o TEST

Steps to reproduce

Built a Docker image from the following Dockerfile:

FROM maven:3.6.3-jdk-11-openj9

WORKDIR /

RUN apt update && apt install -y git curl unzip python3 python3-pip

RUN curl -L https://github.com/OpenAPITools/openapi-json-schema-generator/archive/refs/heads/master.zip -o master.zip \
    && unzip master.zip

WORKDIR /openapi-json-schema-generator-master

RUN mvn clean install

Then built and ran with:

docker build -t openapi-test -f Dockerfile.openapi .
docker run -it --rm openapi-test bash

Then from within docker

java -jar modules/openapi-json-schema-generator-cli/target/openapi-json-schema-generator-cli.jar generate \
    -i /TEST.yaml \
    -g python \
    -t modules/openapi-json-schema-generator/src/main/resources/python \
    -o TEST

And lastly, tried using the generated code:

cd TEST
python3 -m pip install .
python3 -c "import openapi_client.models"

HOWEVER THIS SPEC WORKS (no nesting)

openapi: "3.0.0"
info:
  title: Sample
  version: "1.0.0"
paths:
  /test_one:
    get:
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/my_response"
components:
  schemas:
    my_response:
      type: object
      properties:
        from:
          type: string
        to:
          type: string
      required:
        - from
        - to

Related issues/PRs

OpenAPITools/openapi-generator#7119

Suggest a fix

I am not sure how to fix this, but it seems like the escapeReservedWord function is not being called properly?

Edits

• fixed some code formatting
• fixed typo

[Lnk2past]

Also, adding that --reserved-words-mappings from=from did not help

[Lnk2past]

Thanks for the super fast turnaround on this, confirmed working on my end!

[spacether]

Thank you for filling the issue. You're welcome :)