RequestValidationError is **not** a sub-class of Pydantic's ValidationError

[valentinoli]

First Check

• I added a very descriptive title here.
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Example Code

@app.exception_handler(ValidationError)
async def validation_exception_handler(request: Request, exc: ValidationError):
    return PlainTextResponse(
        str(exc), status_code=status.HTTP_500_INTERNAL_SERVER_ERROR
    )

Description

I was trying to handle both RequestValidationError and ValidationError by writing a custom handler for ValidationError but that doesn't work.

The docs state that

RequestValidationError is a sub-class of Pydantic's ValidationError

However, looking at FastAPI source code reveals that this is not the case.

Operating System

Linux

Operating System Details

No response

FastAPI Version

0.101.0

Pydantic Version

2.1.1

Python Version

3.11.3

Additional Context

No response

[Kludex]

• I've created RequestValidationError is **not** a sub-class of Pydantic's ValidationError #10786 from this discussion. Thanks.