Pyright/Pylance inconsistency: Unknown import symbol sklearn

[einarwar]

Environment data

• Language Server version: 2024.9.1
• OS and version: linux x64
• Python version (and distribution if applicable, e.g. Anaconda): 3.12.6
• python.analysis.indexing: true
• python.analysis.typeCheckingMode: basic
• scikit-learn version: 1.5.2
• pyright version: 1.1.380
• Runs in a devcontainer

I have been having an annoyance for some time, where pylance and pyright behaves inconsistently.

from sklearn.metrics import root_mean_squared_error

Pyright does not flag this as an issue, while pylance gives the error:

"root_mean_squared_error" is unknown import symbolPylance[reportAttributeAccessIssue](https://github.com/microsoft/pyright/blob/main/docs/configuration.md#reportAttributeAccessIssue)

When i select sklearn.metrics -> go to definition using the python environment where sklearn is installed, i get to site-packages/sklearn/metrics/__init__.py where root_mean_squared_error correctly is.

If i however select a python interpreter without sklearn installed, when i go to the definition, i am directed to home/vscode/.vscode-server/extensions/ms-python.vscode-pylance-2024.9.1/dist/bundled/stubs/sklearn/metrics/__init__.pyi, where the function root_mean_squared_error does not exist.

Expected behavior

Would expect pylance to behave as pyright in this case, i.e give no error

Actual behavior

Pylance raises an error, while pyright doesn't

Logs

When checking the output from Python Language Server, there are two entries that might be related:

2024-09-18 19:22:34.475 [info] [Info  - 7:22:34 PM] (31165) [BG(1)] Long operation: checking: file:///usr/local/lib/python3.12/site-packages/sklearn/metrics/__init__.py (4947ms)
2024-09-18 19:22:34.481 [info] [Info  - 7:22:34 PM] (31165) [BG(1)] Long operation: analyzing: file:///usr/local/lib/python3.12/site-packages/sklearn/metrics/__init__.py (4956ms)

[rchiodo]

Thanks for the issue. This is because our bundled type stubs don't match your scikit-learn version. The stubs here need to be updated:
https://github.com/microsoft/python-type-stubs/tree/main/stubs/sklearn

[einarwar]

Thanks for the quick response. Should i raise an issue in that repo as well?

[rchiodo]

Yeah it wouldn't hurt. Somebody might have the time to update those stubs.

[einarwar]

Took the matter into my own hands: microsoft/python-type-stubs#317

One question though: Is this expected behaviour by pylance? I have read about the differences between pylance and pyright, e.g useLibraryCodeForTypes. I tried with this setting both enabled and disabled, without any effect. I would have thought that the default behaviour regardless would be to inspect the package if it was installed. However, scikit-learn does not have a py.typed file, which might have an effect here

[debonte]

Took the matter into my own hands: microsoft/python-type-stubs#317

Thanks @einarwar! I just merged your PR. It will show up in next week's prerelease build.

useLibraryCodeForTypes. I tried with this setting both enabled and disabled, without any effect.

useLibraryCodeForType only comes into play when no stubs are found. You can read more about our resolution order here.

[StellaHuang95]

This issue has been fixed in prerelease version 2024.9.102, which we've just released. You can find the changelog here: CHANGELOG.md