Issue number: #5303

Summary

Changes

In Pydantic v2, when validating a model that has a field with a type of another model can break the validation. This limitation/bug in Pydantic is causing problems for customers trying to validate JSON against complex model structures

To work around this issue, we are modifying the validation code to use a try/except block. If a NotImplementedError is raised during JSON validation, we can fall back to using validate_python instead.

I added additional tests to make sure we are covering this part of code and also a e2e test.

User experience

import json
from typing import Any, Dict, Type, Union

from pydantic import BaseModel

from aws_lambda_powertools.utilities.parser import parse
from aws_lambda_powertools.utilities.typing import LambdaContext

AnyInheritedModel = Union[Type[BaseModel], BaseModel]
RawDictOrModel = Union[Dict[str, Any], AnyInheritedModel]

#payload = {"name": "powertools", "profile": {"description": "python", "size": "XXL"}}

class ModelWithUnionType(BaseModel):
    name: str
    profile: RawDictOrModel


def lambda_handler(event: ModelWithUnionType, context: LambdaContext):
    event = json.dumps(event)

    event_parsed = parse(event=event, model=ModelWithUnionType)

    return {"name": event_parsed.name}

Checklist

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• Meet tenets criteria
• I have performed a self-review of this change
• Changes have been tested
• Changes are documented
• PR title follows conventional commit semantics

Acknowledgment

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