Errors disappear after saving any changes to file

[levrik]

Errors from mypy disappear after saving any change to a file. It doesn't matter if the change fixes an error, introduces a new error or is not related at all. Only reloading VS Code window fixes it until you make a change once again. This basically makes this extension unusable.

mypy-related settings in my settings.json:

{
  "python.linting.mypyEnabled": false
}

When set to false:

Errors only reported by Python extension.

When set to true:

Errors reported by this and Python extension.

After having saved changes when set to true:

Error from this extension disappears while the one from Python extension stays.

Logs of this extension after saving changes which cause errors to disappear:

2023-07-14 14:12:20.364 [info] /Users/levrik/code/<REDACTED>/.venv/bin/python -m mypy.dmypy --status-file /var/folders/y5/_yxr_tgx3xggc344718g4fp00000gn/T/.vscode.dmypy_status/status-f7231085-f699-494e-93e9-916f03e88602.json run -- --no-color-output --no-error-summary --show-absolute-path --show-column-numbers --show-error-code --no-pretty --follow-imports=normal --show-error-end /Users/levrik/code/<REDACTED>.py
2023-07-14 14:12:20.364 [info] [Trace - 2:12:20 PM] Received notification 'window/logMessage'.
2023-07-14 14:12:20.364 [info] CWD Server: /Users/levrik/code/<REDACTED>
2023-07-14 14:12:20.437 [info] [Trace - 2:12:20 PM] Received notification 'window/logMessage'.
2023-07-14 14:12:20.437 [info] file:///Users/levrik/code/<REDACTED>.py :

2023-07-14 14:12:20.439 [info] [Trace - 2:12:20 PM] Received notification 'textDocument/publishDiagnostics'.

[karthiknadig]

@levrik This might be a bug in mypy itself. We don't specifically cache any result or do anything special here. You can try installing mypy in your environment and set "mypy-type-checker.path": ["${workspaceFolder}/.venv/bin/mypy"]. This will run mypy directly instead of using dmypy.

[karthiknadig]

See python/mypy#15677

[levrik]

@karthiknadig Thanks. Keeping an eye on the linked issue.