fix(parser): support TypeAdapter instances as models

[leandrodamascena]

Issue number: #5476

Summary

Changes

The current implementation of event_parser fails when a TypeAdapter instance is provided as the model. This is due to an attempt to cast an existing TypeAdapter into a new TypeAdapter, which results in a PydanticSchemaGenerationError.

Changes Made

1. Modified _retrieve_or_set_model_from_cache function to check if the input is already a TypeAdapter instance.
2. If the input is a TypeAdapter, it's returned directly from the cache without additional wrapping.
3. Maintained backwards compatibility for non-TypeAdapter models.

User experience

This code works now.

from typing import Literal, Union, Annotated

from pydantic import Field, TypeAdapter

# from aws_lambda_powertools.utilities.parser import event_parser

from aws_lambda_powertools.utilities.parser.models.event_bridge import EventBridgeModel
from aws_lambda_powertools.utilities.parser.models.s3 import (
    S3EventNotificationEventBridgeDetailModel,
)

class S3EventNotificationEventBridgeModel(EventBridgeModel):
    detail: S3EventNotificationEventBridgeDetailModel
    source: Literal["aws.s3"]


class ScheduledNotificationEventBridgeModel(EventBridgeModel):
    source: Literal["aws.events"]


EventBridgeSource = Annotated[
    Union[S3EventNotificationEventBridgeModel, ScheduledNotificationEventBridgeModel],
    Field(discriminator="source"),
]

EventBridgeModelAdapter = TypeAdapter(Union[EventBridgeSource, EventBridgeModel])

@event_parser(model=EventBridgeModelAdapter)
def handler(event: EventBridgeModelAdapter, context):
    print(f'Got event, parsed into {type(event)=}')

Checklist

If your change doesn't seem to apply, please leave them unchecked.

• 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

Is this a breaking change?

RFC issue number:

Checklist:

• Migration process documented
• Implement warnings (if it can live side by side)

Acknowledgment

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

Disclaimer: We value your time and bandwidth. As such, any pull requests created on non-triaged issues might not be successful.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.16%. Comparing base (fdc9416) to head (24a5902).
Report is 2 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #5535   +/-   ##
========================================
  Coverage    96.16%   96.16%           
========================================
  Files          229      229           
  Lines        10810    10812    +2     
  Branches      2007     2008    +1     
========================================
+ Hits         10395    10397    +2     
  Misses         327      327           
  Partials        88       88           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud