Static typing: allow to pass dict as argument to exception classes #7279
Description
Static type checker used
mypy (project's standard)
AWS Lambda function runtime
3.13
Powertools for AWS Lambda (Python) version
latest
Static type checker info
When trying to call this endpoint, a application/json response is returned, but the typing in the exception classes from event_handler/exceptions.py only allow str.
http -v :3000/hello/bob
GET /hello/bob HTTP/1.1
Accept: */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Host: localhost:3000
User-Agent: HTTPie/3.2.4
HTTP/1.1 404 NOT FOUND
Connection: close
Content-Length: 82
Content-Type: application/json
Date: Fri, 29 Aug 2025 09:31:53 GMT
Server: Werkzeug/3.1.3 Python/3.13.7
{
"message": {
"msg": "no person named bob",
"type": "name.not_found"
},
"statusCode": 404
}
Code snippet
from aws_lambda_powertools.event_handler import APIGatewayRestResolver
from aws_lambda_powertools.event_handler.exceptions import NotFoundError
app = APIGatewayRestResolver()
@app.get("/hello/<name>")
def hello_name(name: str):
raise NotFoundError(
{
"type": "name.not_found",
"msg": f"no person named {name}",
}
)
def lambda_handler(event, context):
return app.resolve(event, context)Possible Solution
A simple fix would be to change
class ServiceError(Exception):
"""Powertools class HTTP Service Error"""
def __init__(self, status_code: int, msg: str):with
class ServiceError(Exception):
"""Powertools class HTTP Service Error"""
def __init__(self, status_code: int, msg: str | dict):But I'm not familiar enough with the codebase to know if this can cause other issues.