python-lsp-pyre

This is a plugin for the Python LSP Server.

It implements support for calling Meta's Pyre type checker via a subprocess.

Pyre does offer a language server of its own, and that may be more useful to you if your editor supports multiple language servers per language.

Features

This plugin adds the following features to python-lsp-server:

• Type linting via Meta's Pyre (pyre-check)

Installation

To use this plugin, you need to install this plugin in the same virtualenv as python-lsp-server itself.

pip install python-lsp-pyre

or to make it a development requirement in Poetry

poetry add -G dev python-lsp-pyre

Then run python-lsp-server as usual, the plugin will be auto-discovered by python-lsp-server if you've installed it to the right environment. Refer to python-lsp-server and your IDE/text editor documentation on how to setup python-lsp-server. The plugin's default enabled status is True.

Editor integration

• An example is provided for KDE's Kate editor

Configuration

Meta's Pyre uses .pyre_configuration files in your project to set up lint controls. It does not read pyproject.toml.

On first run of this plugin, it will detect a missing .pyre_configuration and write out one for you if the create-pyre-config configuration option is enabled. It relies on the workspace root passed to the language server for this write. This file is not immutable, and the reference documentation may be useful.

You can also use pyre init instead to set up the configuration.

The configuration written by this plugin is:

{
    "site_package_search_strategy": "all",
    "source_directories": [
        "."
    ],
    "exclude": [
        "/setup.py",
        ".*/build/.*"
    ],
    "strict": true
}

The noteable difference from pyre init is the change to the search strategy ("pep561" to "all"), and turning on strict mode as the default. You may find strict mode a bit pedantic, but having worked with strict mode for several years, I highly recommend it.

If the .pyre_configuration file is not present (or has a syntax error), the LSP error log, LSP output, and your editor's LSP messages will display an ABEND message containing the error from Pyre as it fails to run.

Squelching Pyre lint errors

The recommended way of squelching a Pyre warning is to pick one of # pyre-ignore or # pyre-fixme. More precisely, suppose Pyre is indicating

Missing global annotation [5]: Globally accessible variable `logger` has type `logging.Logger` but no type is specified.

at you, and you do not feel like typing your logger right now. On the line before, you can put either one of

• # pyre-ignore[5] Don't care about logger
• # pyre-fixme[5] Resolve this when doing all logger work

to squelch the lint, and provide a hint to future you (or other readers of the code). This is a trivial example; it's easier to just type the logger.

You do not need to match the number in the brackets, other than for ease of cross-reference with the type errors documentation.

When you address the squelched error, Pyre will indicate that the comment is not suppressing a type error and can be removed.

Developing

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

git clone https://github.com/cricalix/python-lsp-pyre python-lsp-pyre
cd python-lsp-pyre
pip install -e '.[dev]'

Alterately, if you use Poetry,

git clone https://github.com/cricalix/python-lsp-pyre python-lsp-pyre
cd python-lsp-pyre
poetry install

will set up a virtualenv if necessary, install all dependencies, and then install this project in editable/development mode.

Contributing

This plugin was written to scratch an itch. If you find it useful, great!

If something about it annoys you, or you think there's a better way to do something, you're welcome to send a PR.