pydantic.v1.parse_obj_as internally uses pydantic.main.create_model instead of pydantic.v1.main.create_model

[SharathHuddar]

Initial Checks

• I confirm that I'm using Pydantic V2 installed directly from the main branch, or equivalent

Description

I was trying to migrate my codebase from V1 to V2 (mostly by replacing import pydantic with import pydantic.v1) and noticed that pydantic.v1.parse_obj_as was not working as intended and was leading to the following error:

Traceback (most recent call last):
  File "/Users/sharathhuddar/workspace/django-rest-api/core/tests/test_types.py", line 177, in test_non_https_url
    parse_obj_as(HttpsUrl, url)
  File "/Users/sharathhuddar/workspace/django-rest-api/django-rest-api-3.7/lib/python3.7/site-packages/pydantic/v1/tools.py", line 37, in parse_obj_as
    model_type = _get_parsing_type(type_, type_name=type_name)  # type: ignore[arg-type]
  File "/Users/sharathhuddar/workspace/django-rest-api/django-rest-api-3.7/lib/python3.7/site-packages/pydantic/v1/tools.py", line 30, in _get_parsing_type
    return create_model(type_name, __root__=(type_, ...))
  File "/Users/sharathhuddar/workspace/django-rest-api/django-rest-api-3.7/lib/python3.7/site-packages/pydantic/main.py", line 1319, in create_model
    return meta(__model_name, resolved_bases, namespace, __pydantic_reset_parent_namespace__=False, **kwds)
  File "/Users/sharathhuddar/workspace/django-rest-api/django-rest-api-3.7/lib/python3.7/site-packages/pydantic/_internal/_model_construction.py", line 96, in __new__
    namespace, config_wrapper.ignored_types, class_vars, base_field_names
  File "/Users/sharathhuddar/workspace/django-rest-api/django-rest-api-3.7/lib/python3.7/site-packages/pydantic/_internal/_model_construction.py", line 279, in inspect_namespace
    raise TypeError("To define root models, use `pydantic.RootModel` rather than a field called '__root__'")
TypeError: To define root models, use `pydantic.RootModel` rather than a field called '__root__'

On inspecting the source code, I noticed that parse_obj_as calls _get_parsing_type which inturn calls pydantic.main.create_model instead of pydantic.v1.main.create_model

The issue gets resolved on updating the import statement in pydantic.v1.tools._get_parsing_type: 24 from from pydantic.main import create_model to from pydantic.v1.main import create_model

Example Code

No response

Python, Pydantic & OS Version

python -c "import pydantic.version; print(pydantic.version.version_info())"

             pydantic version: 2.0
        pydantic-core version: 2.0.1 release build profile
                 install path: /Users/sharathhuddar/workspace/django-rest-api/django-rest-api-3.7/lib/python3.7/site-packages/pydantic
               python version: 3.7.12 (default, Nov 22 2022, 14:45:00)  [Clang 13.1.6 (clang-1316.0.21.2.5)]
                     platform: Darwin-22.2.0-x86_64-i386-64bit
     optional deps. installed: ['email-validator', 'typing-extensions']

Selected Assignee: @lig

[SharathHuddar]

Looks like this bug crept in because V1 code that is copied over to pydantic.v1 has absolute import path. Have raised a PR with relative import path

[hramezani]

Fixed in 2c0e2a6

[SharathHuddar]

@hramezani when can I expect this to be released ?

[Kludex]

@SharathHuddar We are going to make a release today.

[jsntcy]

@Kludex, once the fix is released, please let us know.

[Kludex]

Sorry, we didn't make it to release it yesterday, but for sure it will be released today.

You can watch our releases selecting "Watch" -> "Custom" -> "Releases":

[jsntcy]

@Kludex @hramezani, the issue still exists using the new version.
We use: pydantic-2.0.1 pydantic-core-2.0.2

Source code for the dependency: https://github.com/Azure/partnercenter-cli-extension/blob/main/partnercenter/setup.py#L39-L43

[hramezani]

@jsntcy Based on the error picture that you posted, Your codebase is using Pydantic V1. We had a lot of changes in Pydantic V2. So, to fix the problem, you need to

• Update your code base to Pydantic V2 based on migration guide
• Or, Still using Pydantic V1. to do this you need to change the imports. e.g. from pydantic import BaseModel has to be changed to from pydantic.v1 import BaseModel
• Or, if you are not ready to migrate to V2, pin pydantic to <2

[wangzelin007]

@jsntcy Based on the error picture that you posted, Your codebase is using Pydantic V1. We had a lot of changes in Pydantic V2. So, to fix the problem, you need to

• Update your code base to Pydantic V2 based on migration guide
• Or, Still using Pydantic V1. to do this you need to change the imports. e.g. from pydantic import BaseModel has to be changed to from pydantic.v1 import BaseModel
• Or, if you are not ready to migrate to V2, pin pydantic to <2

@hramezani,
we ping pydantic to < 2, and actually installed the pydantic 1.10.11, it gives another error TypeError: unsupported operand type(s) for |: 'ModelMetaclass' and 'NoneType', any suggestion?