since the owner just closed my issue on GitHub and the people on the official discord server couldn't help me, I'm trying my luck here.
Since NestJS doesn't have interceptors or anything else for fastify (for file uploads), I wanted to use the fastify-multipart (now @fastify/multipart) package. I registered the middleware the normal way, but I'm using the attachFieldsToBody option, so I can properly use the validation pipeline which I've set to global. I have a very simple setup with a DTO for my post request. If you let the sandbox container run, you'll see the 500 error saying maximum call stack exceeded which happened in the validation pipeline.
GitHub Issue: https://github.com/nestjs/nest/issues/9683
Sandbox: https://codesandbox.io/s/nestjs-fastify-multipart-bug-17m5ls
The multipart middleware works fine (even though someone on Discord thought that was an issue, assuming that I didn't google for it). The only issue is the validation pipeline, but I can't track this down, I'm unsure why it causes an infinite loop. While I'm debugging and looking through the common package source code, if anyone ran into this issue or has an idea for a solution, please let me know.
