Prerequisites

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

Fastify version

5.4.0

Plugin version

No response

Node.js version

22.11.0

Operating system

macOS

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

15.5

Description

Errors thrown from a custom validator while using an async preValidation hook are not caught by the error handler. Instead the error is unhandled and propagated to the Node runtime which kills the app. Removing the hook all together or using a synchronous approach (with done()) resolves the issue.

This issue seems similar to #2707

Link to code that reproduces the bug

https://github.com/jakedipity/scratchspace/tree/main/fastify-bug

Expected Behavior

Error handler should be called (we should see a setErrorHandler <Error> logged), the client is given a response, and the instance continues running. Instead the handler is not called, the connection socket hangs up, and the instance crashes.