pre-commit.linter_python

#!/bin/bash
#
# Copyright (c) 2017, United States Government, as represented by the
# Administrator of the National Aeronautics and Space Administration.
#
# All rights reserved.
#
# The Astrobee platform is licensed under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with the
# License. You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

py_changed=$(git diff --diff-filter=d --cached --name-only | grep '\.py$')

# If py_changed is empty exit success
if [ -z "${py_changed}" ]; then
  echo "=================================================="
  echo "  No Python files changed, no checks needed."
  exit 0
fi

failed_lint=false

command -v black > /dev/null 2>&1
ans=$?
if [ "$ans" -ne "0" ]; then
    echo "'black' was not found. To install, check https://github.com/psf/black."
    echo "Note that black requires Python 3.6.2+ to run."
    exit 0
fi

command -v isort > /dev/null 2>&1
ans=$?
if [ "$ans" -ne "0" ]; then
    echo "'isort' was not found. To install, check https://github.com/PyCQA/isort."
    exit 0
fi

echo "=================================================="
echo "  Analysing python code style with 'black'."
# This check the files but they will not be commited
if `black . --include ${py_changed} --check --quiet`; then
    echo "Linter checks using 'black' passed."
else
    echo "Errors detected with 'black'. Fixing them. Try to add and commit your files again."
    black . --include ${py_changed}
    failed_lint=true
fi

echo "=================================================="
echo "  Analysing python code style with 'isort'."

# We're running isort recursively on the top-level folder (not
# limiting it to the changed files) in order to match how it is
# invoked in the CI workflow. This is because isort determines what
# imports are treated as first party, and therefore should be grouped
# separately, in part based on what files it is asked to process. We
# definitely don't want to have any disagreement where this pre-commit
# hook wants things grouped one way but the CI workflow says that's
# wrong. Note that our intention is for isort to treat all imports
# found in the astrobee repo as first party, and we specify that using
# the src_paths setting in the .isort.cfg file.  But we should still
# run isort consistently in both places to avoid disagreement, which
# could happen for example if the .isort.cfg src_paths list gets out
# of date.

isort_args=(
    "--extend-skip=cmake"
    "--extend-skip=submodules"
    "--extend-skip=debian"
    "--profile=black"
)
if $(isort . "${isort_args[@]}" --diff --check-only --quiet >/dev/null); then
    echo "Linter checks using 'isort' passed."
else
    echo "Errors detected with 'isort'. Fixing them. Try to add and commit your files again."
    isort . "${isort_args[@]}" >/dev/null
    failed_lint=true
fi

# Cancel commit if linter failed
# The user should add manually the corrected files
if ${failed_lint}; then
  exit 1
fi