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

pylsp-mypy supports the use of pyproject.toml for configuration. It can also be configuered using configs provided to the LSP server. The configuration keys are listed in the following.

Configuration

pyproject.toml key	LSP Configuration Key	Type	Description	Default
live_mode	pylsp.plugins.pylsp_mypy.live_mode	boolean	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.	true
dmypy	pylsp.plugins.pylsp_mypy.dmypy	boolean	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.	false
strict	pylsp.plugins.pylsp_mypy.strict	boolean	Refers to the strict option of mypy. This option often is too strict to be useful.	false
overrides	pylsp.plugins.pylsp_mypy.overrides	array of (string items or true)	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.	[true]
dmypy_status_file	pylsp.plugins.pylsp_mypy.dmypy_status_file	string	Specifies which status file dmypy should use. This modifies the --status-file option passed to dmypy given dmypy is active.	.dmypy.json
config_sub_paths	pylsp.plugins.pylsp_mypy.config_sub_paths	array of string items	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	pylsp.plugins.pylsp_mypy.report_progress	boolean	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 live_mode. For large projects, enabling this can be helpful to assure yourself whether mypy is still running.	false
exclude	pylsp.plugins.pylsp_mypy.exclude	array of string items	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.	[]
follow-imports	pylsp.plugins.pylsp_mypy.follow-imports	normal, silent, skip or error	mypy parameter follow-imports. In mypy this is normal by default. We set it silent, to sort out unwanted results. This can cause cache invalidation if you also run mypy in other ways. Setting this to normal avoids this at the cost of a small performance penalty.	silent
mypy_command	pylsp.plugins.pylsp_mypy.mypy_command	array of string items	The command to run mypy. This is useful if you want to run mypy in a specific virtual environment. Requires env variable PYLSP_MYPY_ALLOW_DANGEROUS_CODE_EXECUTION to be set.	[]
dmypy_command	pylsp.plugins.pylsp_mypy.dmypy_command	array of string items	The command to run dmypy. This is useful if you want to run dmypy in a specific virtual environment. Requires env variable PYLSP_MYPY_ALLOW_DANGEROUS_CODE_EXECUTION to be set.	[]

Both mypy_command and dmypy_command could be used by a malicious repo to execute arbitrary code by looking at its source with this plugin active. Still users want this feature. For security reasons this is disabled by default. If you really want it and accept the risks set the environment variable PYLSP_MYPY_ALLOW_DANGEROUS_CODE_EXECUTION in order to activate it.

Using a pyproject.toml for configuration, which is in fact the preferred way, 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 (deprecated) given that it does not contain a pylsp-mypy section. The following explanation uses the syntax of the legacy config file (deprecated). 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
}

With mypy_command your config could look like this:

{
    "enabled": True,
    "mypy_command": ["poetry", "run", "mypy"]
}

With dmypy_command your config could look like this:

{
    "enabled": True,
    "live_mode": False,
    "dmypy": True,
    "dmypy_command": ["/path/to/venv/bin/dmypy"]
}

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.