Mypy linting not working for mypy 0.990 - no issues found

[MetRonnie]

Type: Bug

Behaviour

Expected vs. Actual

Expected: mypy errors are found.

Actual: mypy reports no errors.

Steps to reproduce:

1. Introduce a deliberate type error
2. Run mypy <filepath> on the command line to confirm that the problem is genuine
3. Inspect the Python Output panel to see that you get nothing:

   ##########Linting Output - mypy##########
   
   Success: no issues found in 1 source file
   

Mypy version: mypy 0.990 (compiled: yes)

Edit: I have tested and linting works for mypy 0.981

Diagnostic data

• Python version (& distribution if applicable, e.g. Anaconda): 3.10.6
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Conda
• Value of the python.languageServer setting: Pylance

Output for Python in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Python)

> /opt/conda/bin/conda run -n env_name --no-capture-output python /net/~/.vscode/extensions/ms-python.python-2022.16.1/pythonFiles/get_output_via_markers.py /net/~/.vscode/extensions/ms-python.python-2022.16.1/pythonFiles/linter.py -m mypy --ignore-missing-imports --follow-imports=silent --show-column-numbers --show-error-codes --explicit-package-bases --namespace-packages ./path/to/file.py
cwd: .
##########Linting Output - mypy##########

Success: no issues found in 1 source file

User Settings

condaPath: "<placeholder>"

languageServer: "Pylance"

linting
• mypyArgs: "<placeholder>"
• mypyEnabled: true

formatting
• autopep8Args: "<placeholder>"

testing
• pytestArgs: "<placeholder>"
• pytestEnabled: true

Extension version: 2022.16.1
VS Code version: Code 1.72.2 (d045a5eda657f4d7b676dedbfa7aab8207f8a075, 2022-10-12T22:16:26.920Z)
OS version: Linux x64 3.10.0-1160.76.1.el7.x86_64
Modes:
Sandboxed: No

System Info

Item	Value
CPUs	Intel(R) Xeon(R) CPU E5-2690 v4 @ 2.60GHz (4 x 2599)
GPU Status	2d_canvas: unavailable_software canvas_oop_rasterization: disabled_off direct_rendering_display_compositor: disabled_off_ok gpu_compositing: disabled_software multiple_raster_threads: enabled_on opengl: disabled_off rasterization: disabled_software raw_draw: disabled_off_ok skia_renderer: enabled_on video_decode: disabled_software video_encode: disabled_software vulkan: disabled_off webgl: unavailable_software webgl2: unavailable_software webgpu: disabled_off
Load (avg)	1, 3, 3
Memory (System)	7.62GB (1.80GB free)
Process Argv	--unity-launch --crash-reporter-id 4cb3165e-6680-471f-992f-0c1e623756f7
Screen Reader	no
VM	100%
DESKTOP_SESSION	1-gnome
XDG_CURRENT_DESKTOP	GNOME
XDG_SESSION_DESKTOP	1-gnome
XDG_SESSION_TYPE	x11

[karthiknadig]

There should be a linter command arguments in the Output > python logs. can you run that in the terminal? it should be running linter.py with few arguments.

[MetRonnie]

> /opt/conda/bin/conda run -n env_name --no-capture-output python
    /net/~/.vscode/extensions/ms-python.python-2022.16.1/pythonFiles/get_output_via_markers.py
    /net/~/.vscode/extensions/ms-python.python-2022.16.1/pythonFiles/linter.py -m mypy --ignore-missing-imports
    --follow-imports=silent --show-column-numbers --show-error-codes --explicit-package-bases
    --namespace-packages ./path/to/file.py
cwd: .
##########Linting Output - mypy##########

Success: no issues found in 1 source file

• Not sure why some of the paths show up starting with /net/~/, probably a quirk to do with NFS, but copying and pasting the command and removing the /net/ works for me and shows the mypy errors
• The mypy options come from my settings (python.linting.mypyArgs). Removing them didn't help.

[najtin]

Same issue here, without the /net/ thing. The paths look fine.

• Python version (& distribution if applicable, e.g. Anaconda): 3.10.6, apt ubuntu
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): poetry (i guess they use venv?)
• Value of the python.languageServer setting: Default
• Mypy: 0.990 (can confirm, works with 0.981)

I use poetry and installed flake8 and mypy in a local venv using poetry. Flake works fine but mypy does not report any issues. To be clear it does report something: Success: no issues found in 1 source file But it should instead report an issue with the code.

Here is the code i want to check:

def a() -> str:
    1

Clearly, mypy should complain about the missing return statement.
Here is the output of the Output tab:

LSP Notebooks experiment is disabled -- not using Pylance
LSP Notebooks interactive window support is disabled -- not in LSP Notebooks experiment
> conda info --json
Python interpreter path: ./.venv/bin/python
> ~/.conda/bin/conda info --json
> . ./.venv/bin/activate && echo 'e8b39361-0157-4923-80e1-22d70d46dee6' && python ~/.vscode-oss/extensions/ms-python.python-2022.16.1-universal/pythonFiles/printEnvVariables.py
> ~/.julia/conda/3/bin/conda info --json
> ./.venv/bin/python ~/.vscode-oss/extensions/ms-python.python-2022.16.1-universal/pythonFiles/get_output_via_markers.py ~/.vscode-oss/extensions/ms-python.python-2022.16.1-universal/pythonFiles/interpreterInfo.py
> /bin/python ~/.vscode-oss/extensions/ms-python.python-2022.16.1-universal/pythonFiles/get_output_via_markers.py ~/.vscode-oss/extensions/ms-python.python-2022.16.1-universal/pythonFiles/interpreterInfo.py
> /usr/bin/python ~/.vscode-oss/extensions/ms-python.python-2022.16.1-universal/pythonFiles/get_output_via_markers.py ~/.vscode-oss/extensions/ms-python.python-2022.16.1-universal/pythonFiles/interpreterInfo.py
> ~/.julia/conda/3/bin/python ~/.vscode-oss/extensions/ms-python.python-2022.16.1-universal/pythonFiles/get_output_via_markers.py ~/.vscode-oss/extensions/ms-python.python-2022.16.1-universal/pythonFiles/interpreterInfo.py
Starting Jedi language server for rootsnakes.
> ./.venv/bin/python ~/.vscode-oss/extensions/ms-python.python-2022.16.1-universal/pythonFiles/linter.py -m mypy --follow-imports=silent --ignore-missing-imports --show-column-numbers --no-pretty ./rootsnakes/app.py
cwd: .
> ./.venv/bin/python ~/.vscode-oss/extensions/ms-python.python-2022.16.1-universal/pythonFiles/linter.py -m flake8 ./rootsnakes/app.py
cwd: .
##########Linting Output - mypy##########

Success: no issues found in 1 source file

##########Linting Output - flake8##########

When we run the exact same command in the terminal window (with venv activated) or in a fresh shell without activating the venv we get the expected result:

./.venv/bin/python ~/.vscode-oss/extensions/ms-python.python-2022.16.1-universal/pythonFiles/linter.py -m mypy --follow-imports=silent --ignore-missing-imports --show-column-numbers --no-pretty ./lol.py
lol.py:1:1: error: Missing return statement  [return]
Found 1 error in 1 file (checked 1 source file)

Extension version: 2022.16.1
VSCodium version: VSCodium 1.72.2 (378660f7dd07287aa34acf90e8fec157425c1ac8, 2022-10-16T23:03:19.989Z)
OS version: Linux x64 5.15.0-52-generic snap
Modes:
Sandboxed: No

System Info

Item	Value
CPUs	-
GPU Status	-
Load (avg)	1, 0, 0
Memory (System)	15.19GB (3.28GB free)
Process Argv	--ms-enable-electron-run-as-node --no-sandbox --unity-launch
Screen Reader	no
VM	0%
DESKTOP_SESSION	mate
XDG_CURRENT_DESKTOP	MATE
XDG_SESSION_DESKTOP	mate
XDG_SESSION_TYPE	x11

[karthiknadig]

@najtin For flake8 can you try using the flake8 extension from marketplace https://marketplace.visualstudio.com/items?itemName=ms-python.flake8

[najtin]

I think this is related to the issue above (for completeness python/mypy#14042 )

[najtin]

@najtin For flake8 can you try using the flake8 extension from marketplace https://marketplace.visualstudio.com/items?itemName=ms-python.flake8

No, flake8 works as expected. This issue does also occur when flake8 is not installed.

[karthiknadig]

The difference between mypy 0.982 vs 0.990 is that with 0.990 mypy shows error code.

mypy == 0.982

(.venv) C:\GIT\repro\mypytest>python "C:\Users\kanadig\.vscode\extensions\ms-python.python-2022.19.13131832\pythonFiles\linter.py" -m mypy --follow-imports=silent --ignore-missing-imports --show-column-numbers --no-pretty simple.py
simple.py:1:10: error: Incompatible types in assignment (expression has type "str", variable has type "int")
Found 1 error in 1 file (checked 1 source file)

mypy == 0.990

(.venv) C:\GIT\repro\mypytest>python "C:\Users\kanadig\.vscode\extensions\ms-python.python-2022.19.13131832\pythonFiles\linter.py" -m mypy --follow-imports=silent --ignore-missing-imports --show-column-numbers --no-pretty simple.py
simple.py:1:10: error: Incompatible types in assignment (expression has type "str", variable has type "int")  [assignment]
Found 1 error in 1 file (checked 1 source file)

Even with that difference it seems to be working for me: