Module is incorrectly imported in debugger

[chenly23]

Environment data

• VS Code version: 1.41.1
• Extension version (available under the Extensions sidebar): 2020.1.58038
• OS and version: Ubuntu 16.04.2 LTS
• Python version (& distribution if applicable, e.g. Anaconda): 2.7.12
• Type of virtual environment used (N/A | venv | virtualenv | conda | ...): venv

Expected behaviour

Import the modules from my own files

Actual behaviour

Import the modules from files in vscode-python pythonFiles.

Steps to reproduce:

1. Create a python file (test.py) with the code:

import completion
print(completion)

2. Create an empty file named completion.py
3. Debug test.py with Python: Current File (Integrated Terminal)
   Get the output:

<module 'completion' from '/root/.vscode-server/extensions/ms-python.python-2020.1.58038/pythonFiles/completion.pyc'>

4. Run test.py in terminal
   Get the output:

<module 'completion' from '/workspaceFolder/completion.py'>

As @brettcannon pointed out that the directory of pythonFiles gets put on the sys.path to load the debugger, so the modules clash with the user's files.

[karthiknadig]

@chenly23 Can you share the debugger command line that it puts in the terminal?

[chenly23]

Sorry, the steps to reproduce may be error, since the workspaceFolder in sys.path is in front of vscode-pythonFiles.
The sys.path is:

['/cly', '/root/.vscode-server/extensions/ms-python.python-2020.1.58038/pythonFiles', '/usr/local/lib/python2.7/dist-packages/xblock_simplevideo-0.1-py2.7.egg', '/usr/lib/python2.7', '/usr/lib/python2.7/plat-x86_64-linux-gnu', '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload', '/root/.local/lib/python2.7/site-packages', '/usr/local/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages']

/cly is the workspaceFolder. Now I move the completion.py to the site-packages (simulation of pip install?), so the file tree is

/cly
    test.py
/root/.local/lib/python2.7/site-packages
    completion.py
/usr/bin/python

@karthiknadig then the debugger command line and outputs:

root@DevEnv01:/cly# cd /cly ; env PYTHONIOENCODING=UTF-8 PYTHONUNBUFFERED=1 /usr/bin/python /root/.vscode-server/extensions/ms-python.python-2020.1.58038/pythonFiles/ptvsd_launcher.py --default --client --host localhost --port 42543 /cly/test.py 
<module 'completion' from '/root/.vscode-server/extensions/ms-python.python-2020.1.58038/pythonFiles/completion.pyc'>

and the Run Python File in Terminal command line and outpus:

root@DevEnv01:/cly# /usr/bin/python /cly/test.py
<module 'completion' from '/root/.local/lib/python2.7/site-packages/completion.py'>

[karthiknadig]

@chenly23 This may be an artifact of how we launch the debugger. There is a work around that you can try for now.

workaround:

1. Get the insiders version of the extension from https://pvsc.blob.core.windows.net/extension-builds/ms-python-insiders.vsix .
2. Add this to your settings and reload VSCode. (we added the ability to opt-into experiments recently hence the need for insiders version)

    "python.experiments.optInto": [
        "DebugAdapterFactory - experiment",
        "PtvsdWheels37 - experiment"
    ]

This will force the extension to use a newer version of the debugger, that starts is a slightly different way. This method does not add the pythonFiles directory, that way it should not clash with your completion.py.

[karthiknadig]

Proposed solution:

We should rename our python files to have some sort of prefix that keeps it distinct from something that user might have.

Another solution could be to smartly remove the pythonFiles directory from sys.path before starting the debugger.
PS: Given that we are moving towards the new debugger, I recommend the previous solution.

[chenly23]

@karthiknadig Thanks for the workaround, I will try the insiders version later.
I add preLaunchTask and postDebugTask to remove and recover the completion.py in pythonFiles to avoid clashing.
For the proposed solution, I recommend the files renaming also~

[luabud]

Closing in favour of #4609.