1.9.1 breaks backward compatibility

[pvicente]

Checks

• I added a descriptive title to this issue
• I have searched (google, github) for similar issues and couldn't find anything
• I have read and followed the docs and still think this is a bug

Bug

Output of python -c "import pydantic.utils; print(pydantic.utils.version_info())":

             pydantic version: 1.9.1
            pydantic compiled: True
                 install path: /Users/pedrovicente/cytora/risk-stream-service/.venv/lib/python3.9/site-packages/pydantic
               python version: 3.9.11 (main, May  4 2022, 15:54:04)  [Clang 13.1.6 (clang-1316.0.21.2.3)]
                     platform: macOS-12.3.1-arm64-arm-64bit
     optional deps. installed: ['email-validator', 'typing-extensions']
...

#3713 PR breaks backward compatibility.

I think it should have been released as 2.0 and not as 1.9.1.

No matter it has a default value because there are field_definitions kwargs after it. Mypy was complaining and I had to add cls_kwargs={}, when calling it after updating from 1.9.0 to 1.9.1, so the change is not backward compatible and shouldn't have been a semver patch version release.

   model = pydantic.create_model(
        model_name,
        __config__=None,
        __base__=None,
        __module__=__name__,
        __validators__={},
        **{k: (v, ...) for k, v in attributes.items()},
...

After upgrade from 1.9.0 to 1.9.1 mypy is complaining with:

error: No overload variant of "create_model" matches argument types "str", "None", "None", "str", "Dict[<nothing>, <nothing>]", "Dict[str, Tuple[type, ellipsis]]"

[hramezani]

@pvicente you are right and we are sorry about this.

@samuelcolvin shall we add **Breaking Change in the change of 42acd8f as well?

[PrettyWood]

This was a patch for v1.9 because v1.9.0 actually introduced a regression compared to v1.8.2

[samuelcolvin]

Closing this but happy to add more details to the change log.