ci: add whitespace check #40

	name: Whitespace Check

	on:
	pull_request:
	push:
	branches:
	- master

	jobs:
	whitespace-check:
	runs-on: ubuntu-latest

	steps:
	- name: Set commit count
	shell: bash
	run: echo "COMMIT_DEPTH=$((1 + ${{ github.event.pull_request.commits }}))" >> $GITHUB_ENV

	- name: Checkout code
	uses: actions/checkout@v2
	with:
	fetch-depth: ${{ env.COMMIT_DEPTH }}

	# TODO: reintroduce this check when the library is cleaned up
	# - name: Check for trailing whitespace
	# run: \|
	# TRAILING_WHITESPACE=$(git grep -l -z -E '\s+$' \| xargs -0 sed -n '/\s$/p')
	# if [ -n "$TRAILING_WHITESPACE" ]; then
	# echo "Trailing whitespace found. Please fix with:\
	# bash ./etc/fix_trailing_whitespace.sh"
	# exit 1
	# fi

	- name: Check that every file ends correctly
	run: \|
	while IFS= read -r file; do
	# Check if the file is a regular file
	if [ -f "$file" ]; then
	if [ -n "$(tail -c 1 "$file")" ]; then
	echo "File $file does not end with a newline. Please fix with:\
	bash ./etc/fix_end_newlines.sh"
	exit 1
	fi
	fi
	done < <(git ls-files)

	# Get the repo with the commits(+1) in the series.
	# Process `git log --check` output to extract just the check errors.

	- name: git log --check
	id: check_out
	run: \|
	log=
	base_commit=$(git rev-parse FETCH_HEAD)
	while IFS= read -r line; do
	log="${log}\n${line}"
	echo "::error file=${line%%:},line=${line#:}::Whitespace issue: ${line}"
	done <<< "$(git diff --check $base_commit ${{ github.sha }} \| grep '^-[^-]')"

	if [ -n "${log}" ]; then
	echo -e "Whitespace issues found in the following file(s) and line number(s):\n${log}" >> $GITHUB_OUTPUT
	exit 2
	fi

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