pre-receive.2-commit_message

#!/bin/bash
#
# Guarantees that
#  - commit messages are properly formatted (no full stop in subject, empty line between subject and body)
#  - all commits to any branch contains a signed-off-by line
#  - commits to precious branches additionally are acked-by someone


really_precious_branches=( stable )

zero="0000000000000000000000000000000000000000"

while read oldrev newrev refname; do
	if [ "$newrev" = "$zero" ]; then
		# deletes
		continue
	fi

	if [ "$oldrev" != "$zero" ]; then
		# not a create
		pbranch=$(git rev-parse --symbolic --abbrev-ref $refname) || exit 13
		for lbranch in "${really_precious_branches[@]}"; do
			if [ "$lbranch" = "$pbranch" ]; then
				commit=$(git rev-list -n 1 --all-match --invert-grep -E \
					--grep '^Acked-by: .+ <.+@.+\..+>' "$oldrev..$newrev")
				if [ -n "$commit" ]; then
					echo "No Acked-by found in commit $commit for $refname (from $oldrev..$newrev), not pushing."
					echo "git rev-list -n 1 --all-match --invert-grep -E --grep '^Acked-by: .+ <.+@.+\..+>' $oldrev..$newrev"
					echo "Commit message was:"
					git cat-file commit ${commit} | sed '1,/^$/d' | cat -n
					exit 1
				fi
			fi
			commit=$(git rev-list -n 1 --all-match --invert-grep -E \
				--grep '^Signed-off-by: .+ <.+@.+\..+>' "$oldrev..$newrev")
			if [ -n "$commit" ]; then
				echo "No Signed-off-by found in commit $commit for $refname (from $oldrev..$newrev), not pushing."
				echo "git rev-list -n 1 --all-match --invert-grep -E --grep '^Signed-off-by: .+ <.+@.+\..+>$' $oldrev..$newrev"
				echo "Commit message was:"
				git cat-file commit ${commit} | sed '1,/^$/d' | cat -n
				exit 1
			fi
		done
	fi

	message=$(git cat-file commit ${newrev} | sed '1,/^$/d')
	if [ ""$(echo "$message" | sed -nre '1!d;/.*[^[:alnum:]]$/p') != "" ]; then
		echo "Non-alphanumeric character at the end of the first line of the commit message:"
		echo "$message" | head -n1 | cat -n
		exit 1
	fi
	
	if [ ""$(echo "$message" | sed -nre '2!d;s/^$/empty/p') != "empty" ]; then
		echo "Second line of commit message is not empty:"
		echo "$message" | head -n2 | cat -n
		exit 1
	fi
	
done