Upgrading to nestjs v11 (and fastify v5) does not handle invalid content-type errors from Fastify

[yawhide]

Did you read the migration guide?

• I have read the whole migration guide

Is there an existing issue that is already proposing this?

• I have searched the existing issues

Potential Commit/PR that introduced the regression

No response

NestJS version

11.1.0

Describe the regression

FastifyError with code FST_ERR_CTP_INVALID_MEDIA_TYPE is not being rethrown as an nestjs HttpException.

I have an existing guard that validates content-type to always be application/json and raise a UnsupportedMediaTypeException if not.

But now in nestjs v11, if I make a request with an invalid content-type (say foo), my guard doesnt run and instead I see

FastifyError

code ='FST_ERR_CTP_INVALID_MEDIA_TYPE'
level ='\x1b[31merror\x1b[39m'
message ='Unsupported Media Type: foo'
name ='FastifyError'
statusCode =415

in my custom ExceptionFilter

Minimum reproduction code

https://github.com/yawhide/nestjs-issue-15022

Input code

@Catch(Error)
export class ErrorExceptionFilter extends BaseExceptionFilter {
  catch(error: Error, host: ArgumentsHost) {
    console.log(error) // error is a FastifyError, not HttpException
  }
}

Expected behavior

My custom ExceptionFilter should see an HttpException exception instead of a FastifyError when the content-type is invalid.

Other

No response

[micalevisk]

Please provide a minimum reproduction repository. You can start one by running npm init nest in your terminal

why reproductions are required

[yawhide]

added repo

[kamilmysliwiec]

Let's track this here #15056