Real-time mypy linting disabled when using a plugin

Environment data

VSCode Version: 1.36.1 OS Version: macOS 10.14.5 Python version : 3.7.2 Type of virtual environment used : pyenv viapipenv Relevant/affected Python packages and their versions: N/A Jedi or Language Server? (i.e. what is “python.jediEnabled”): Language Server ("python.jediEnabled": false)

Expected behaviour

When mypy linting is enabled, VSCode should use the mypy.ini and accordingly adopt any plugins that are used and installed, and display real-time warnings/errors in the editor.

Actual behaviour

When a plugin is used, all real-time checking is disabled.

Steps to reproduce:

1. Enable Python and mypy linting in settings.
2. You will see errors (red squiggly line) if you define a function like this one:

def some_func() -> int:
    return "some string"

1. Install a mypy specific plugin. In my case it was django-stubs:

"python.linting.mypyEnabled": true,
    "python.linting.mypyArgs": [
        "--config-file=${workspaceFolder}/mypy.ini"
    ],

and the mypy.ini file contents:

[mypy]
plugins = mypy_django_plugin.main


warn_unused_ignores = True
strict_optional = True
check_untyped_defs = True
follow_imports = silent
ignore_missing_imports = True
show_column_numbers = True

[mypy.plugins.django-stubs]
django_settings_module = my_app.settings.dev

When I run mypy like so:

PYTHONPATH=${PYTHONPATH}:${PWD} mypy core/selectors.py

I get the correct errors, for example:

error: Incompatible return value type (got “int”, expected “Iterable[SomeModel]”)

But this is not highlighted in my editor in real-time/after save.

However, if I remove the plugin section from the mypy.ini file, I do get an error in the editor:

Incompatible return value type (got “int”, expected “Iterable[SomeModel]”) mypy(error)

[karrtikr]

Thanks for cooperating. As I am not able to reproduce this, I would’ve to ask you to try few things.

• ~/.virtualenvs/myvirtualenv/bin/python -m mypy --config-file=/Users/myusername/Projects/project_root/mypy.ini ~/Projects/project_root/accounts/models.py

Try running this command in the terminal. I expect to see error Error constructing plugin instance of NewSemanalDjangoPlugin.

• Now try initializing PYTHONPATH variable followed by the command

$ PYTHONPATH=${PYTHONPATH}:${PWD}

$ ~/.virtualenvs/myvirtualenv/bin/python -m mypy --config-file=/Users/myusername/Projects/project_root/mypy.ini ~/Projects/project_root/accounts/models.py

If the second one works, it means extension is not initializing the PYTHONPATH environment variable like it should.

Also, could you try a different interpreter and see if it reproduces the issue?

[karrtikr]

Try to choose a different Python version interpreter, with mypy installed. Maybe one without virtualenv.

python.pythonPath setting gets set when you choose a python interpreter.