generateStaticParams globalThis (global) singleton problem

[devweissmikhail]

Link to the code that reproduces this issue

https://github.com/vaneenige/next-app-router-singleton

To Reproduce

1. Set a new key in the global object
2. Try to get this key from the global object inside generateStaticParams

Current vs. Expected behavior

I expected the global object to be the same in this environment

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 23.6.0: Mon Jul 29 21:14:30 PDT 2024; root:xnu-10063.141.2~1/RELEASE_ARM64_T6030
  Available memory (MB): 18432
  Available CPU cores: 12
Binaries:
  Node: 20.11.1
  npm: 10.2.4
  Yarn: N/A
  pnpm: 9.5.0
Relevant Packages:
  next: 14.2.5 // Latest available version is detected (14.2.5).
  eslint-config-next: N/A
  react: 18.3.1
  react-dom: 18.3.1
  typescript: 5.5.4
Next.js Config:
  output: export

Which area(s) are affected? (Select all that apply)

Performance, Runtime

Which stage(s) are affected? (Select all that apply)

next dev (local), next build (local)

Additional context

For example, I declare a new key in the global object using instrumentation.ts (it doesn't really matter where you do it)

When I try to get it inside the generateStaticParams function, I get undefined

But after trying the same thing in the component, I got the expected result:

I found similar issues and they seem to be related:
#65350
#52165

It seems to be running in a separate environment. But how can I solve this problem?