Faster PyCharm mypy plugin with daemon dmypy

mypy.py

#!/usr/bin/env python3

import argparse
import os
import subprocess
import sys

STATUS_FILE = os.path.join(os.path.dirname(__file__), ".dmypy.json")


def virtualenv_path():
    script_dir = os.path.dirname(os.path.abspath(__file__))
    return os.path.join(script_dir, ".venv")


def main():
    venv_path = virtualenv_path()
    mypy_bin = os.path.join(venv_path, "bin", "mypy")
    dmypy_bin = os.path.join(venv_path, "bin", "dmypy")

    parser = argparse.ArgumentParser(description="Wrapper for dmypy and mypy")
    parser.add_argument("-V", action="store_true", help="Responds with mypy version", default=False)
    parser.add_argument("--follow-imports", type=str, help="Ignored")
    parser.add_argument("--show-column-numbers", action="store_true", help="Ignored", default=False)

    parsed_args, unknown_args = parser.parse_known_args()

    if parsed_args.V:
        # The PyCharm plugin uses `-V` to test the existence of mypy binary
        command = [mypy_bin, "-V"]
    else:
        # All other calls should be passed to dmypy
        command = [
            dmypy_bin,
            "--status-file",
            STATUS_FILE,
            "run",
            "--",
            "--follow-imports",
            "skip",
            "--show-column-numbers",
        ] + unknown_args

    return subprocess.run(command)


if __name__ == "__main__":
    result = main()
    sys.exit(result.returncode)