#!/bin/bash
# SPDX-License-Identifier: GPL-2.0

#
# This file is part of Lustre, http://www.lustre.org/
#
# contrib/git-hooks/prepare-commit-msg
#
# A Git hook script to prepare the commit log message.  Install into
# lustre/.git/hooks/prepare-commit-msg to enable for Lustre commits.
#
# Called by git-commit with the name of the file that has the
# commit message, followed by the description of the commit
# message's source.  The hook's purpose is to edit the commit
# message file.  If the hook fails with a non-zero status,
# the commit is aborted.
#
# Commit hook to check the patch against the Lustre coding style.
# It adds any checkpatch warnings/errors as commit comments, which
# means that they can currently be ignored, but are at least visible.
#

CHECKPATCH=${CHECKPATCH:-contrib/scripts/checkpatch.pl}
CHECKPATCH_OPTS=${CHECKPATCH_OPTS:-"--no-signoff --no-tree"}
SHELLCHECK=${SHELLCHECK:-$(which shellcheck)}
SHELLCHECK_OPTS=${SHELLCHECK_OPTS:-" -f gcc "}
SHELLCHECK_RUN=${SHELLCHECK_RUN:-"yes"} # run everytime by default

# If there are no comments in the commit, it is likely a rebase and
# this shouldn't be adding new comments, or they appear in the commit.
grep -q "^#" "$1" || exit 0

# Add a commented-out Test-Parameters: line. This will let the developer
# uncomment it out if they think it's appropriate.
echo "#" >> "$1"
echo "# If this patch makes only non-functional changes, or test-only" >> "$1"
echo "# changes, consider adding this 'Test-Parameters' in the" >> "$1"
echo "# commit message:" >> "$1"
echo "#" >> "$1"
echo "# Test-Parameters: trivial" >> "$1"
echo "#" >> "$1"
echo "# If you need to repeat the same subtest many times, consider" >> "$1"
echo "# this instead:" >> "$1"
echo "#" >> "$1"
echo "# Test-Parameters: trivial testlist=sanity env=ONLY=1,ONLY_REPEAT=100" >> "$1"
echo "#" >> "$1"
echo "# https://wiki.whamcloud.com/display/PUB/Changing+Test+Parameters+with+Gerrit+Commit+Messages" >> "$1"
echo "#" >> "$1"

# Add a commented-out Signed-off-by: line.  This shouldn't be added in an
# uncommented form, otherwise sanity checking for an emtpy commit fails.
# The developer should uncomment it to include it in the commit message.
echo "#" >> "$1"
echo "# The 'Signed-off-by' line signifies that you agree to the Developer" >> "$1"
echo "# Certificate of Origin - https://developercertificate.org/" >> "$1"
echo "#" >> "$1"
SIGNOFF=$(git var GIT_AUTHOR_IDENT | sed -n 's/^\(.*>\).*$/Signed-off-by: \1/p')
grep -qs "^$SIGNOFF" "$1" || echo "# $SIGNOFF" >> "$1"

# Add the checkpatch.pl output as comments, but don't cause a commit error
# yet, as there may be exceptions and it is better let a person decide.
if [ -x "$CHECKPATCH" ]; then
	echo "" >> "$1"
	echo "#" >> "$1"
	[ -d ".git/rebase-apply" -o -d ".git/rebase-merge" ] &&
		DIFFOPT="HEAD" || DIFFOPT="--cached"
	git diff $DIFFOPT | $CHECKPATCH $CHECKPATCH_OPTS - |
		sed -e 's/^/# /' >> "$1"
fi

# Add the shellcheck output as comments, but don't cause a commit error.
if [[ -x "$SHELLCHECK" && "$SHELLCHECK_RUN" == "yes" ]]; then
	# Add header
	echo "#" >> "$1"
	echo "# shellcheck output:" >> "$1"
	echo "#" >> "$1"
	# Get file that needs to be shellchecked. We only consider *.sh files
	# Example Start --
	#       modified:   lustre/tests/sanity.sh
	#       modified:   contrib/git-hooks/prepare-commit-msg
	#            new:   lustre/utils/liblustreapi_error.c
	# Example End   --
	mod_files=($(awk '/modified:.*\.sh|new:.*\.sh/ { print $3 }' $1))
	for cur_file in ${mod_files[@]}; do
		# Shebangs should prefer bash over regular sh. This allows
		# scripts to freely use bash-isms and lowers the risks of
		# failures on Debian based platforms. Output a small warning
		# if #!/bin/sh is found.
		echo "#" $(grep -Hn "#\!/bin/sh" "$cur_file" && \
			echo " : Please don't use sh in shebangs.") >> "$1"

		# Get start/end range of lines that needs to be reported
		# range presently not used will come in handy when dealing with
		# warnings reported by shellcheck
		# Example 'git show' output Start --
		#       @@ -29,6 +29,7 @@ DEF_STRIPE_COUNT=-1
		# Example 'git show' output End   --
		range=($(git show $cur_file | awk '/^@@/ { print $3 }' | \
			sed -e 's/+//' -e 's/,/ /'))
		start_line=${range[0]}
		end_line=$((start_line + ${range[1]}))

		# 'shellcheck' reports errors/warnings/notes as below:
		# Example start ---
		#        sanity-lnet.sh:2319:13: error: Double quote array \
		#        expansions to avoid re-splitting elements. [SC2068]
		#
		#        sanity-lnet.sh:2421:27: note: Double quote to prevent \
		#        globbing and word splitting. [SC2086]
		#
		#        sanity-lnet.sh:2411:8: warning: Declare and assign \
		#        separately to avoid masking return values. [SC2155]
		# Example end   ---
		$SHELLCHECK $SHELLCHECK_OPTS $cur_file |
			while IFS=": " read -r file line char mtype msg; do
			# Only filter out "errors" reported by shellcheck
			# We ignore "warnings" and "notes" for now.
			# TODO "Warnings" reported by shellcheck will come later
			[[ "$mtype" == "error" ]] || continue
			# Empty line we skip it.
			[[ -n "$line" ]] || continue
			echo "# $file:$line:$char $mtype: $msg" >> "$1"
		done
	done
	echo "#" >> "$1"
fi

# Cause Vim to wrap text at 70 columns to match commit message style.
# Adding a matching emacs modeline would be good, if I knew how to do that.
echo "# vim:textwidth=70:" >> "$1"

# Add these comments at the end
# So that Vim does not pretend
# The "echo" above is actually
# A modeline for this file. Savvy?