Cannot find implementation or library stub for module named "..." for modules inside .../Python14/Lib/site-packages

[ItsCubeTime]

I installed first via pip install zuban --break-system-packages --upgrade then the extension via the VS Code marketplace.

I had a go using PYTHONPATH like so:

but it doesnt seem to pick up on it. The actual value is C:\Users\olliv\AppData\Local\Programs\Python\Python314\Lib\site-packages;C:\PythonPathLibraries (which the windows env var editor displays as shown above)

I then tried by placing a pyproject.toml file at the project root containing:

[tool.zuban]
mypy_path = ["C:/Users/olliv/AppData/Local/Programs/Python/Python314/Lib/site-packages","C:/PythonPathLibraries"]

Which gives me an error:

thread 'zubanls:main' (67492) panicked at crates\zuban_python\src\file\flow_analysis.rs:1701:36:
RefCell already mutably borrowed
[Error - 1:07:16 PM] Request textDocument/inlayHint failed.
  Message: Server panicked, will now restart (version 0.8.2)
  Code: -32603 
2026-07-06T13:07:16.2359066+02:00 ERROR Expected tuple.__new__ to return the tuple class
2026-07-06T13:07:16.2359281+02:00 ERROR To crash on this error, use set the environment variable ZUBAN_CRASH_ON_ERROR=1
Panic context:
> C:\Users\olliv\AppData\Local\Programs\Python\Python314\Lib\site-packages\pyperclip\__init__.py


thread 'zubanls:main' (67492) panicked at crates\zuban_python\src\file\flow_analysis.rs:1701:36:
RefCell already mutably borrowed
[Error - 1:07:16 PM] Request textDocument/documentHighlight failed.
  Message: Server panicked, will now restart (version 0.8.2)
  Code: -32603 
2026-07-06T13:07:16.3529164+02:00 ERROR Expected tuple.__new__ to return the tuple class
2026-07-06T13:07:16.3529334+02:00 ERROR To crash on this error, use set the environment variable ZUBAN_CRASH_ON_ERROR=1
Panic context:
> C:\Users\olliv\AppData\Local\Programs\Python\Python314\Lib\site-packages\pyperclip\__init__.py


thread 'zubanls:main' (67492) panicked at crates\zuban_python\src\file\flow_analysis.rs:1701:36:
RefCell already mutably borrowed
[Error - 1:07:16 PM] Request textDocument/codeAction failed.
  Message: Server panicked, will now restart (version 0.8.2)
  Code: -32603 
2026-07-06T13:07:16.465389+02:00 ERROR Expected tuple.__new__ to return the tuple class
2026-07-06T13:07:16.4654109+02:00 ERROR To crash on this error, use set the environment variable ZUBAN_CRASH_ON_ERROR=1
Panic context:
> C:\Users\olliv\AppData\Local\Programs\Python\Python314\Lib\site-packages\pyperclip\__init__.py


thread 'zubanls:main' (67492) panicked at crates\zuban_python\src\file\flow_analysis.rs:1701:36:
RefCell already mutably borrowed
[Error - 1:07:16 PM] Request textDocument/semanticTokens/full failed.
  Message: Server panicked, will now restart (version 0.8.2)
  Code: -32603 

I do however seem to get autocompletion for modules inside the directories specified in pyproject.toml, but all syntax coloring breaks (presumably because of the error displayed above?). On a side note though, as I do not really use pyproject.toml for most of my projects, I would very much like to see a (working) global way of configurating zuban, like a global (system wide) pyproject.toml or via VS Code's settings.json - and it could also be handy if zuban were able to pick up on "python.analysis.extraPaths": ["C:/wherever/one/likes/perhaps/python14/lib/site-packages"], (a setting in VS Codes settings.json created by MS Python extension)

[ItsCubeTime]

As a separate question, can we disable the typehint suggestions?

[davidhalter]

As a separate question, can we disable the typehint suggestions?

I don't think so currently, but feel free to open an issue about it. There might also be a VSCode/editor specific setting where you can change it, since this could very well be handled on client side as well.

[ItsCubeTime]

Figured I would provide my project files as well in case they are useful for any reason:
fast_pbr_viewport_render.zip
Which depends on:

• fast.zip (I have this module located so its __init__.py is at C:\PythonPathLibraries\fast\__init__.py)
• https://github.com/nutti/fake-bpy-module installed via pip install fake-bpy-module-latest which then ends up in C:\Users\olliv\AppData\Local\Programs\Python\Python314\Lib\site-packages\bpy-stubs alongside some sister modules like ...\site-packages\mathutils

[davidhalter]

Expected tuple.new to return the tuple class

This sounds like a Typeshed issue. Something in the vendored? typeshed seems to be wrong or different. Did you edit something?

Zuban essentially crashes because an assertion is wrong with typeshed. The tuple signature seems off. I'm not sure that's the reason, but it might be.

---

Other than that zuban_python\src\file\flow_analysis.rs:1701 sounds like a bug that is known (e.g. #264) and that I'm currently trying to fix, but it's a pretty nasty one that might take some time. If you can reproduce it reliably without imports feel free to also open an issue about that.

[ItsCubeTime]

No I mentioned everything I did :) I did however have an old install of ZubanLS MS extension before redoing the installation now (from over a year ago). I just ran the pip install zuban --break-system-packages --upgrade, uninstalled the ZubanLS extension and installed it once more with VS Codes UI

    {
      "metadata": {
        "metadata_version": "2.4",
        "name": "zuban",
        "version": "0.9.0",
        "summary": "Zuban - The Zuban Language Server",
        "description": "#########################\nThe Zuban Language Server\n#########################\n\nA Mypy-compatible Python Language Server and type checker built in Rust.\n\nMore infos: https://zubanls.com\n\nDocs\n====\n\nhttps://docs.zubanls.com\n\nLicense\n=======\n\nAGPL, https://github.com/zubanls/zuban/blob/master/LICENSE\n\n",
        "description_content_type": "text/x-rst; charset=UTF-8",
        "keywords": [
          "typechecking",
          "mypy",
          "static",
          "analysis",
          "autocompletion"
        ],
        "home_page": "https://zubanls.com",
        "author_email": "Dave Halter <info@zubanls.com>",
        "license_expression": "AGPL-3.0-only",
        "license_file": [
          "licenses.html"
        ],
        "classifier": [
          "Development Status :: 1 - Planning",
          "Environment :: Console",
          "Intended Audience :: Developers",
          "License :: Other/Proprietary License",
          "Operating System :: OS Independent",
          "Programming Language :: Python",
          "Programming Language :: Python :: 3.7",
          "Programming Language :: Python :: 3.8",
          "Programming Language :: Python :: 3.9",
          "Programming Language :: Python :: 3.10",
          "Programming Language :: Python :: 3.11",
          "Programming Language :: Python :: 3.12",
          "Programming Language :: Python :: 3.13",
          "Programming Language :: Python :: 3.14",
          "Programming Language :: Python :: 3.15",
          "Programming Language :: Python :: 3 :: Only",
          "Programming Language :: Python :: 3",
          "Programming Language :: Rust",
          "Topic :: Text Editors :: Integrated Development Environments (IDE)",
          "Topic :: Software Development :: Libraries :: Python Modules",
          "Topic :: Software Development :: Quality Assurance",
          "Topic :: Utilities"
        ],
        "requires_python": ">=3.7",
        "project_url": [
          "Documentation, https://docs.zubanls.com",
          "Repository, https://github.com/zubanls/zubanls-python"
        ]
      },
      "metadata_location": "C:\\Users\\olliv\\AppData\\Local\\Programs\\Python\\Python314\\Lib\\site-packages\\zuban-0.9.0.dist-info",
      "installer": "pip",
      "requested": true
    }
  ],
  "environment": {
    "implementation_name": "cpython",
    "implementation_version": "3.14.3",
    "os_name": "nt",
    "platform_machine": "AMD64",
    "platform_release": "11",
    "platform_system": "Windows",
    "platform_version": "10.0.22631",
    "python_full_version": "3.14.3",
    "platform_python_implementation": "CPython",
    "python_version": "3.14",
    "sys_platform": "win32"
  }

[ItsCubeTime]

As for repro.... you can just use the files I provided a little above :) Wont take more than 5 mins to set that up as I have it

[davidhalter]

Yeah, but that's not a good repro. This involves third-party code. A good repro would be 10-20 lines of code with 1-3 files. I'm 100% sure that it's preproducible that way.

Are the errors still the same?

[ItsCubeTime]

@davidhalter In that case, how do I find out what part of the dependencies is the cause? I dont see any line numbers mentioned in the log, here is that pyperclip.init.py nonetheless:
init.py

[davidhalter]

You have to do what I would do as well, continue to remove code until there's only a few lines. I typically delete the non-stdlib imports first to make sure there are as few dependencies as possible and after that I just remove half of the code of a file iteratively and see if the error still reproduces and repeat that.