next-on-pages environment related information

 System:
        Platform: darwin
        Arch: arm64
        Version: Darwin Kernel Version 23.2.0: Wed Nov 15 21:55:06 PST 2023; root:xnu-10002.61.3~2/RELEASE_ARM64_T6020
        CPU: (12) arm64 Apple M2 Max
        Memory: 64 GB
        Shell: /bin/zsh
Package Manager Used: npm (9.8.1)

Relevant Packages:
        @cloudflare/next-on-pages: 1.9.0
        vercel: 33.5.2
        next: 14.1.0

Description

next-on-pages breaks when using Next's default instrumentation @vercel/otel, resulting in the following error:

... rest of next build
⚡️ Completed `npx vercel build`.

⚡️ ERROR: A duplicated identifier has been detected in the same function file, aborting.

⚡️ Please report this at https://github.com/cloudflare/next-on-pages/issues.

Reproduction

Repo: https://github.com/Maronato/next-on-pages-instrumentation-repro

Steps to reproduce:

1. Create a new project with npm create cloudflare@latest next-on-pages -- --framework=next
2. Install @vercel/otel (npm install @vercel/otel)
3. Add experimental: { instrumentationHook: true } to your next config
4. Create a new file in the src or root of the project called instrumentation.ts
5. Paste the following contents:

// src/instrumentation.ts

import { registerOTel } from "@vercel/otel"

export function register() {
  registerOTel()
}

6. Build with npx next-on-pages

Pages Deployment Method

None

Pages Deployment ID

No response

Additional Information

The error seems to happen in this function, but I'm not sure why.

A few notes:

• Calling registerOTel is not required. Simply printing it (console.log(registerOTel)) is enough to cause the error
• Vercel made the repo private, so I can't inspect the code https://github.com/vercel/otel
• The code that they ship is minified
• They say that you can use OTEL's libraries directly but it only works with Node. To use with edge you have to use their library

Would you like to help?

• Would you like to help fixing this bug?