Throwing error in setErrorHandler after a JSON parse SyntaxError causes app to crash

[RigoTamas]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Fastify version

4.26.2

Plugin version

No response

Node.js version

20.12.2

Operating system

Linux

Operating system version (i.e. 20.04, 11.3, 10)

5.10.211-1-MANJARO

Description

Throwing any error in the setErrorHandler function after a JSON parse syntax error causes the app to crash.
Code to reproduce:

import fastify from 'fastify';

const main = async () => {
  const fastifyServer = fastify();
  fastifyServer.setErrorHandler((_error, _request, _reply) => {
    // Using `throw error` crashes the app as well.;
    throw new Error('something');
  });

  fastifyServer.post('/foo', (_req, res) => {
    res.status(200);
    res.send({ ok: true });
  });

  fastifyServer.listen({ port: 8000 });
};

void main();

Running the following request with a syntax error in the JSON body will crash the app:

curl --location --request POST 'localhost:8000/foo' \
--header 'Content-Type: application/json' \
--data-raw '{ "foo": "bar"'

Link to code that reproduces the bug

No response

Expected Behavior

Expected behavior would be that the thrown error is propogated to the root error handler.