Unstable import resolution in jupyter notebook

[WXZhao7]

Environment data

• Pylance version: ms-python.vscode-pylance@2025.3.2
• OS and version: Arch, Linux 6.8.12-8-pve
• Python version (& distribution if applicable, e.g. Anaconda): Python 3.12.9

The env is created by conda create -n test python=3.12 numpy pandas matplotlib obspy pygmt scipy -c conda-forge.

Code Snippet

nb1.ipynb, nb11.ipynb, dir1/nb1.ipynb, dir2/nb1.ipynb

import numpy
import matplotlib
import pygmt
import obspy

numpy.random.random(10)

Repro Steps

1. create a new env with conda create -n test python=3.12 numpy pandas matplotlib obspy pygmt scipy -c conda-forge.
2. install extensions and switch python.analysis.logLevel to Trace

3. reopen VScode and open nb1.ipynb, nb11.ipynb, dir1/nb1.ipynb, dir2/nb1.ipynb

case 1, nb11 Import "numpy" could not be resolved

case 2, dir1/nb1 Import "numpy" could not be resolved

case 3, both nb11 and dir1/nb1 Import "numpy" could not be resolved

Actual behavior

pylance sometimes can't resolve ipynb with same or similar import correctly.

logs

case1.log
case2.log

[Ark-kun]

Yeah. Pylance is always broken the 1st time.

[WXZhao7]

Additionally, this problem can't be fixed by reopening files :(

[rchiodo]

It's hard to see in your screen shots, but what kernel did you select in the notebooks with the problem? That determines where Pylance looks for the imports.

[rchiodo]

I can see it in the logs. This error here:

Could not resolve source for 'matplotlib' in file '/home/wxz/temp/pytest/nb11.ipynb.py'
2025-03-17 01:34:14.315 [info] [Info  - 1:34:14 AM] (288697)   Looking in root directory of execution environment 'file:///home/wxz/temp/pytest'
2025-03-17 01:34:14.315 [info] [Info  - 1:34:14 AM] (288697)   Attempting to resolve using root path 'file:///home/wxz/temp/pytest'
2025-03-17 01:34:14.315 [info] [Info  - 1:34:14 AM] (288697)   Finding python search paths
2025-03-17 01:34:14.315 [info] [Info  - 1:34:14 AM] (288697)   Executing interpreter: '/home/wxz/temp/pytest'
2025-03-17 01:34:14.315 [info] [Info  - 1:34:14 AM] (288697)   Received 0 paths from interpreter
2025-03-17 01:34:14.315 [info] [Info  - 1:34:14 AM] (288697)   No python interpreter search path

For some reason pylance thinks your interpreter is set to /home/wxz/temp/pytest (that's what we're getting as the path to the kernel)

[rchiodo]

Is that your python.defaultInterpreterPath? That would explain the behavior.

[jmsprt]

I believe Pylance is not able to detect the kernel that is remembered per notebook by code.
I am having the same issues, but loading the global python 1.13.1 kernel and then changing back to my conda(base), where all my dependencies are installed, fixes things.

[rchiodo]

The jupyter extension is supposed to provide us with the path to the kernel's interpreter. That should be logged by the Python extension in the output for the Python extension.

For me I get something like this:

2025-03-17 09:44:25.134 [info] Active interpreter [c:\Users\rchiodo\source\repos\pylance-release\testing\single\src\notebook.ipynb]:  C:\Users\rchiodo\source\testing\test_pylance\CondaEnv\python.exe

[rchiodo]

I think this is the root cause of the problem:
microsoft/vscode-jupyter#15965

Same issue. @DonJayamanne did you ever end up creating the API to fire an event when the kernel changes? It looks like this is reproing again. Pylance isn't getting an event to indicate the environment changed.

[rchiodo]

I can work around this problem by adding another kernel to the 'Select Kernel' button and then switching back and forth between the two.

[DonJayamanne]

@rchiodo You can now use the Python extension API to
Change landed in the last release of Python extension.

• Get the Interpreter associated with the Jupyter notebook
  Pass the Uri of the notebook to getActiveEnvironmentPath(<Notebook Uri>)
• To detect change to the interpreter (kernel) of a notebook, listen to the onDidChangeActiveEnvironmentPath event.
  The argument resource will contain the Uri of the notebook where applicable.

here's the corresponding PR microsoft/vscode-python#24771