Mypy plugin for PYLSP

This is a plugin for the Python LSP Server.

It, like mypy, requires Python 3.8 or newer.

Installation

Install into the same virtualenv as python-lsp-server itself.

pip install pylsp-mypy

Configuration

live_mode (default is True) provides type checking as you type.

This writes to a tempfile every time a check is done. Turning off live_mode means you must save your changes for mypy diagnostics to update correctly.

dmypy (default is False) executes via dmypy run rather than mypy.

This uses the dmypy daemon and may dramatically improve the responsiveness of the pylsp server, however this currently does not work in live_mode. Enabling this disables live_mode, even for conflicting configs.

strict (default is False) refers to the strict option of mypy.

This option often is too strict to be useful.

overrides (default is [True]) specifies a list of alternate or supplemental command-line options.

This modifies the options passed to mypy or the mypy-specific ones passed to dmypy run. When present, the special boolean member True is replaced with the command-line options that would've been passed had overrides not been specified. Later options take precedence, which allows for replacing or negating individual default options (see mypy.main:process_options and mypy --help | grep inverse).

dmypy_status_file (Default is .dmypy.json) specifies which status file dmypy should use.

This modifies the --status-file option passed to dmypy given dmypy is active.

config_sub_paths (default is []) specifies sub paths under which the mypy configuration file may be found.

For each directory searched for the mypy config file, this also searches the sub paths specified here

report_progress (default is False) report basic progress to the LSP client.

With this option, pylsp-mypy will report when mypy is running, given your editor supports LSP progress reporting. For small files this might produce annoying flashing in your editor, especially in with live_mode. For large projects, enabling this can be helpful to assure yourself whether mypy is still running.

exclude (default is []) A list of regular expressions which should be ignored.

The mypy runner wil not be invoked when a document path is matched by one of the expressions. Note that this differs from the exclude directive of a mypy config which is only used for recursively discovering files when mypy is invoked on a whole directory. For both windows or unix platforms you should use forward slashes (/) to indicate paths.

This project supports the use of pyproject.toml for configuration. It is in fact the preferred way. Using that your configuration could look like this:

[tool.pylsp-mypy]
enabled = true
live_mode = true
strict = true
exclude = ["tests/*"]

A pyproject.toml does not conflict with the legacy config file given that it does not contain a pylsp-mypy section. The following explanation uses the syntax of the legacy config file. However, all these options also apply to the pyproject.toml configuration (note the lowercase bools). Depending on your editor, the configuration (found in a file called pylsp-mypy.cfg in your workspace or a parent directory) should be roughly like this for a standard configuration:

{
    "enabled": True,
    "live_mode": True,
    "strict": False,
    "exclude": ["tests/*"]
}

With dmypy enabled your config should look like this:

{
    "enabled": True,
    "live_mode": False,
    "dmypy": True,
    "strict": False
}

With overrides specified (for example to tell mypy to use a different python than the currently active venv), your config could look like this:

{
    "enabled": True,
    "overrides": ["--python-executable", "/home/me/bin/python", True]
}

With dmypy_status_file your config could look like this:

{
    "enabled": True,
    "live_mode": False,
    "dmypy": True,
    "strict": False,
    "dmypy_status_file": ".custom_dmypy_status_file.json"
}

With config_sub_paths your config could look like this:

{
    "enabled": True,
    "config_sub_paths": [".config"]
}

With report_progress your config could look like this:

{
    "enabled": True,
    "report_progress": True
}

Developing

Install development dependencies with (you might want to create a virtualenv first):

pip install -r requirements.txt

The project is formatted with black. You can either configure your IDE to automatically format code with it, run it manually (black .) or rely on pre-commit (see below) to format files on git commit.

The project is formatted with isort. You can either configure your IDE to automatically sort imports with it, run it manually (isort .) or rely on pre-commit (see below) to sort files on git commit.

The project uses two rst tests in order to assure uploadability to pypi: rst-linter as a pre-commit hook and rstcheck in a GitHub workflow. This does not catch all errors.

This project uses pre-commit to enforce code-quality. After cloning the repository install the pre-commit hooks with:

pre-commit install

After that pre-commit will run all defined hooks on every git commit and keep you from committing if there are any errors.