`dict(model)` errors when field name `keys` exists

[zzstoatzz]

Initial Checks

• I confirm that I'm using Pydantic V2

Description

A user of ours opened this issue, which appeared to show that dumping a model with dict(...) breaks if you have field on the model whose name is literally keys - which I was able to reproduce.

This error was certainly unexpected to me - I couldn't find an open or closed related issue, but apologies if I'm missing something. I couldn't immediately find a fix for this looking at BaseModel.__iter__ and a bit elsewhere, but will come back to this to try and add a fix later.

Example Code

from pydantic import BaseModel

errored = False


class A(BaseModel):
    keys: str


a = A(keys="hello")

assert a.model_dump() == {"keys": "hello"}

try:
    dict(a)
except TypeError as exc:
    errored = True
    assert "'str' object is not callable" in str(exc)
    print(f"`dict(A(keys='hello'))` errored with {exc}")

assert errored

Python, Pydantic & OS Version

             pydantic version: 2.9.2
        pydantic-core version: 2.23.4
          pydantic-core build: profile=release pgo=false
                 install path: /Users/nate/github.com/prefecthq/prefect/.venv/lib/python3.12/site-packages/pydantic
               python version: 3.12.5 (main, Aug  6 2024, 19:08:49) [Clang 15.0.0 (clang-1500.3.9.4)]
                     platform: macOS-14.6.1-arm64-arm-64bit
             related packages: fastapi-0.115.0 mypy-1.11.2 pydantic-extra-types-2.9.0 pydantic-settings-2.5.2 typing_extensions-4.12.2
                       commit: unknown

[Viicos]

Hello @zzstoatzz,

you are hitting an annoying Python behavior reported here. I'm going to try to update the Python documentation because the behavior is probably going to stay the same.

As a workaround (which I'm going to document in the Pydantic documentation), you can call dict(iter(model)).

[sydney-runkle]

Closing for now, I think this issue represents good enough documentation of this problem + workaround. Thanks @Viicos!

[zzstoatzz]

thanks for the info @Viicos - sounds good! 👍

[Viicos]

Docs PR, hopefully this will be clarified: python/cpython#125213