Debugging matplotlib in VSCode encounters TypeError: 'NoneType' object is not callable

[Tian-Jionglu]

• VS Code Version: 1.68.1;
• Python Extension Version: v2022.8.0;
• OS Version: MacOS 12.4;
• Python Version: 3.10.4;
• Matplotlib Version: 3.5.2;
• Pandas Version: 1.3.4 ( 1.4.2 also tested);

Steps to Reproduce:

1. snippet to reproduce the problem:

   import matplotlib.pyplot as plt
   import pandas as pd
   
   data = pd.DataFrame()
   
   plt.pie([1, 2, 3, 5])
   plt.show()
   

   It returns TypeError: 'NoneType' object is not callable, when using debugging (F5) in VSCode.
2. when pandas clauses are commented, the error flees:

   import matplotlib.pyplot as plt
   # import pandas as pd
   
   # data = pd.DataFrame()
   
   plt.pie([1, 2, 3, 5])
   plt.show()
   

The initial code [1] runs well in other IDE. I suppose there is something wrong in Python Extension.

And here is the Traceback:

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/runpy.py", line 196, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "/Users/my/.vscode/extensions/ms-python.python-2022.8.0/pythonFiles/lib/python/debugpy/launcher/__main__.py", line 97, in <module>
    main()
  File "/Users/my/.vscode/extensions/ms-python.python-2022.8.0/pythonFiles/lib/python/debugpy/launcher/__main__.py", line 53, in main
    launcher.connect(host, port)
  File "/Users/my/.vscode/extensions/ms-python.python-2022.8.0/pythonFiles/lib/python/debugpy/launcher/../../debugpy/launcher/__init__.py", line 34, in connect
    sock.connect((host, port))
ConnectionRefusedError: [Errno 61] Connection refused
Backend MacOSX is interactive backend. Turning interactive mode on.

There are similar issues sumerc/yappi#97 and matplotlib/matplotlib#22333.

[bschnurr]

still having this issue?
on windows it seems to work.

you have selected the correct python environment?
what version of pylance extension do you have installed?

[int19h]

@BSchurr This is a debugger issue; the error message is occurring at runtime.

@fabioz, going by the referenced issues in other repos, this has something to do with PyFrame_FastToLocals; it appears that we must be using PyEval_GetLocals on Python 3.10+ instead.

[fabioz]

I'll investigate.

[fabioz]

@Tian-Jionglu This seems like the same issue in #801.

It seems pandas 1.4.3 still wasn't released with a newer version of cython (so, users are still seeing this):
pandas-dev/pandas#47429
pandas-dev/pandas#46610

[fabioz]

Note that unlike yappi we don't call PyFrame_FastToLocals anywhere -- we do call PyFrame_LocalsToFast but only if the user does an evaluation or changes a local variable, so, the fix applied there isn't applicable here.

The real fix is having a pandas/numpy toolchain which is built with a fixed version of cython so that tracing can be installed while using those and that's outside of the scope of the debugger, so, I'm closing this issue -- see comments in #801.

p.s.: this only affects Mac OS.

[Tian-Jionglu]

@fabioz Thanks for explanation.