Bug: OpenAPI docs fail to generate with certain validators and pydantic v1

[sergeyk93]

Description

OpenAPI docs fail to generate when a request payload is a pydantic v1 model and has a str field with a validator combination of a default(or default_factory) and max_length. Removing any of the validators resolves the issue; it's only reproducible with their combination.
Reproducible with:
Python: 3.11.6
Litestar: 2.8.2
Pydantic: 1.10.15

URL to code causing the issue

No response

MCVE

from litestar import Controller, post
from pydantic.fields import Field
from pydantic.main import BaseModel

OPENAPI_CONTROLLER_TAG = "OpenApiTest"


class TestDto(BaseModel):
    test_str: str = Field(default="some_default", max_length=100)


class OpenApiTestController(Controller):
    path = "/test-openapi"

    @post(
        path="/test",
        tags=[OPENAPI_CONTROLLER_TAG],
        summary="Test",
    )
    async def test(self, data: TestDto) -> str:
        return "success"

Steps to reproduce

1. Add the above controller to your litestar app.
2. Load any variation of OpenAPI UI(I reproduced with swagger, redoc, rapiddoc).

Screenshots

"![SCREENSHOT_DESCRIPTION](SCREENSHOT_LINK.png)"

Logs

ERROR - 2024-05-05 09:36:30,092 - litestar - config - exception raised on http connection to route /schema/redoc

Traceback (most recent call last):
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/serialization/msgspec_hooks.py", line 141, in encode_json
    return msgspec.json.encode(value, enc_hook=serializer) if serializer else _msgspec_json_encoder.encode(value)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/serialization/msgspec_hooks.py", line 88, in default_serializer
    raise TypeError(f"Unsupported type: {type(value)!r}")
TypeError: Unsupported type: <class 'method_descriptor'>

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/middleware/exceptions/middleware.py", line 219, in __call__
    await self.app(scope, receive, send)
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/routes/http.py", line 82, in handle
    response = await self._get_response_for_request(
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/routes/http.py", line 134, in _get_response_for_request
    return await self._call_handler_function(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/routes/http.py", line 154, in _call_handler_function
    response_data, cleanup_group = await self._get_response_data(
                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/routes/http.py", line 205, in _get_response_data
    data = route_handler.fn(**parsed_kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/_openapi/plugin.py", line 161, in _handler
    return plugin_.render(request, self.provide_openapi_schema())
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/openapi/plugins.py", line 310, in render
    self.render_json(request, openapi_schema),
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/openapi/plugins.py", line 70, in render_json
    return encode_json(openapi_schema, serializer=get_serializer(request.route_handler.resolve_type_encoders()))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/serialization/msgspec_hooks.py", line 143, in encode_json
    raise SerializationException(str(msgspec_error)) from msgspec_error
litestar.exceptions.base_exceptions.SerializationException: Unsupported type: <class 'method_descriptor'>
Traceback (most recent call last):
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/serialization/msgspec_hooks.py", line 141, in encode_json
    return msgspec.json.encode(value, enc_hook=serializer) if serializer else _msgspec_json_encoder.encode(value)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/serialization/msgspec_hooks.py", line 88, in default_serializer
    raise TypeError(f"Unsupported type: {type(value)!r}")
TypeError: Unsupported type: <class 'method_descriptor'>

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/middleware/exceptions/middleware.py", line 219, in __call__
    await self.app(scope, receive, send)
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/routes/http.py", line 82, in handle
    response = await self._get_response_for_request(
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/routes/http.py", line 134, in _get_response_for_request
    return await self._call_handler_function(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/routes/http.py", line 154, in _call_handler_function
    response_data, cleanup_group = await self._get_response_data(
                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/routes/http.py", line 205, in _get_response_data
    data = route_handler.fn(**parsed_kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/_openapi/plugin.py", line 161, in _handler
    return plugin_.render(request, self.provide_openapi_schema())
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/openapi/plugins.py", line 310, in render
    self.render_json(request, openapi_schema),
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/openapi/plugins.py", line 70, in render_json
    return encode_json(openapi_schema, serializer=get_serializer(request.route_handler.resolve_type_encoders()))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/serialization/msgspec_hooks.py", line 143, in encode_json
    raise SerializationException(str(msgspec_error)) from msgspec_error
litestar.exceptions.base_exceptions.SerializationException: Unsupported type: <class 'method_descriptor'>
INFO:     127.0.0.1:61936 - "GET /schema/redoc HTTP/1.1" 500 Internal Server Error
INFO:     127.0.0.1:61936 - "GET /favicon.ico HTTP/1.1" 404 Not Found
ERROR - 2024-05-05 09:36:30,309 - litestar - config - exception raised on http connection to route /favicon.ico

Traceback (most recent call last):
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/_asgi/routing_trie/traversal.py", line 153, in parse_path_to_route
    node, path_parameters, path = traverse_route_map(
                                  ^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/_asgi/routing_trie/traversal.py", line 54, in traverse_route_map
    raise NotFoundException()
litestar.exceptions.http_exceptions.NotFoundException: 404: Not Found

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/middleware/exceptions/middleware.py", line 219, in __call__
    await self.app(scope, receive, send)
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/_asgi/asgi_router.py", line 86, in __call__
    asgi_app, scope["route_handler"], scope["path"], scope["path_params"] = self.handle_routing(
                                                                            ^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/_asgi/asgi_router.py", line 102, in handle_routing
    return parse_path_to_route(
           ^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/_asgi/routing_trie/traversal.py", line 170, in parse_path_to_route
    raise NotFoundException() from e
litestar.exceptions.http_exceptions.NotFoundException: 404: Not Found
Traceback (most recent call last):
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/_asgi/routing_trie/traversal.py", line 153, in parse_path_to_route
    node, path_parameters, path = traverse_route_map(
                                  ^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/_asgi/routing_trie/traversal.py", line 54, in traverse_route_map
    raise NotFoundException()
litestar.exceptions.http_exceptions.NotFoundException: 404: Not Found

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/middleware/exceptions/middleware.py", line 219, in __call__
    await self.app(scope, receive, send)
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/_asgi/asgi_router.py", line 86, in __call__
    asgi_app, scope["route_handler"], scope["path"], scope["path_params"] = self.handle_routing(
                                                                            ^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/_asgi/asgi_router.py", line 102, in handle_routing
    return parse_path_to_route(
           ^^^^^^^^^^^^^^^^^^^^
  File "{project_parent_dir}/litestar-playground/.venv/lib/python3.11/site-packages/litestar/_asgi/routing_trie/traversal.py", line 170, in parse_path_to_route
    raise NotFoundException() from e
litestar.exceptions.http_exceptions.NotFoundException: 404: Not Found

Litestar Version

2.8.2

Platform

• Linux
• Mac
• Windows
• Other (Please specify in the description above)

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[peterschutt]

Can you test against https://github.com/litestar-org/litestar/tree/3471-pydantic-v1-field-default please?

[sergeyk93]

@peterschutt Tested & verified, thanks! What version is this change gonna be in?

[github-actions]

This issue has been closed in #3476. The change will be included in the upcoming patch release.

[github-actions]

A fix for this issue has been released in v2.9.0