python_lint.py

#!/usr/bin/env python3

# This source file is part of the Swift.org open source project
#
# Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
# Licensed under Apache License v2.0 with Runtime Library Exception
#
# See https://swift.org/LICENSE.txt for license information
# See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
#


"""
Utility script used to run the flake8 linter over all the project Python
sources.
"""


importos
importsubprocess
importsys


__all__= [
'lint',
]


# -----------------------------------------------------------------------------
# Constants

_UTILS_DIR=os.path.abspath(os.path.dirname(__file__))
_PROJECT_DIR=os.path.dirname(_UTILS_DIR)

_REQUIRED_PACKAGES= [
'flake8',
'flake8-import-order',
]

_INSTALL_FLAKE8_MESSAGE="""
The flake8 and flake8-import-order Python packages are required for linting,
but these were not found on your system.

You can install these using:

 python3 -m pip install flake8
 python3 -m pip install flake8-import-order

For more help, see http://flake8.pycqa.org.
"""


# -----------------------------------------------------------------------------
# Helpers

def_is_package_installed(name):
"""Runs the pip command to check if a package is installed.
 """

command= [
sys.executable,
'-m', 'pip',
'show', '--quiet',
name,
 ]

withopen(os.devnull, 'w') asdevnull:
status=subprocess.call(command, stderr=devnull)

returnnotstatus


# -----------------------------------------------------------------------------

deflint(args, verbose=False):
all_packages_installed=all([
_is_package_installed(name)
fornamein_REQUIRED_PACKAGES
 ])

ifnotall_packages_installed:
ifverbose:
print(_INSTALL_FLAKE8_MESSAGE)

return1

returnsubprocess.call(
 [sys.executable, '-m', 'flake8'] +args,
cwd=_PROJECT_DIR,
universal_newlines=True)


if__name__=='__main__':
sys.exit(lint(sys.argv[1:], verbose=True))