hooks/commit-msg

#!/bin/sh

MSG="$1"

# Check for, and add if missing, a unique Change-Id
#
add_ChangeId() {
	if grep '^Change-Id: ' "$MSG" >/dev/null
	then
		return
	fi

	id=$(_gen_ChangeId)
	out="$MSG.new"
	ftt="$MSG.footers"
	sed -e  '/^[A-Za-z][A-Za-z0-9-]*: /,$d' <"$MSG" >"$out"
	sed -ne '/^[A-Za-z][A-Za-z0-9-]*: /,$p' <"$MSG" >"$ftt"
	if ! [ -s "$ftt" ]
	then
		echo >>"$out"
	fi
	echo "Change-Id: I$id" >>"$out"
	cat "$ftt" >>"$out"
	mv -f "$out" "$MSG"
	rm -f "$out" "$ftt"
}
_gen_ChangeIdInput() {
	echo "tree $(git write-tree)"
	if parent=$(git rev-parse HEAD^0 2>/dev/null)
	then
		echo "parent $parent"
	fi
	echo "author $(git var GIT_AUTHOR_IDENT)"
	echo "committer $(git var GIT_COMMITTER_IDENT)"
	echo
	cat "$MSG"
}
_gen_ChangeId() {
	_gen_ChangeIdInput |
	git hash-object -t commit --stdin
}


add_ChangeId