debutil-backport

#!/bin/sh
# -*- sh -*-
#
# This script intends to simplify backporting debian packages by taking care
# of basic actions.
# It fetches the package at specified revision and updates changelog according
# to your target release.
# Once you are done with backporting related modifications, just use
# debutil-build to build the package.

set -e

usage() {
	cat <<EOF
Usage: $(basename $0) [OPTIONS] PACKAGE_NAME FROM_RELEASE TO_RELEASE

Options:
  -h, --help             Shows this help message
EOF

	exit 2
}

# Restore pwd
restore() {
	cd "${OLD_PWD}"
}

get_version() {
	sed -n -r 's/^Version: //p' "${1}" | head -n1
}

get_upstream_version() {
	get_version "${1}" | sed -n -r 's/([0-9]+:)?(.*)-(.*)$/\2/p'
}

# Prepare backport folder
prepare() {
	local uversion source_pkg

	# we are going to fetch a bunch of files, let's put that in a directory
	OLD_PWD="$(pwd)"

	mkdir "${PACKAGE}"
	cd "${PACKAGE}"

	apt-get source -t ${FROM_RELEASE} ${PACKAGE}

	dsc_file="$(find . -mindepth 1 -maxdepth 1 -type f -name "*_${VERSION}.dsc")"
	source_pkg="$(sed -n -r 's/^Source: //p' "${dsc_file}")"
	dversion="$(get_version "${dsc_file}")"
	uversion="$(get_upstream_version "${dsc_file}")"

	cd "${source_pkg}-${uversion}"
	dch -v "${VERSION}~${BPO}+1" -b \
		--distribution "${TO_RELEASE}-backports" \
		--force-distribution \
		"Backport to ${TO_RELEASE}."

	echo "Please check debian/control"
	cd ..
}

# Option parsing

GETOPT=$(getopt -u -o h -l help, -n "$0" -- "$@")

if [ $? != 0 ]; then
	echo "Try '$(basename $0) --help' for more information."
	exit 1
fi

eval set -- "${GETOPT}"

while [ $# -gt 0 ]; do
	case "$1" in
		--) shift; break ;;
		*) usage ;;
	esac
done

if [ $# -ne 3 ]; then
	usage
fi

PACKAGE=$1
FROM_RELEASE=$2
TO_RELEASE=$3

case "${TO_RELEASE}" in
	jessie) BP0="bpo80" ;;
	wheezy) BPO="bpo70" ;;
	squeeze) BPO="bpo60" ;;
	lenny) BPO="bpo50" ;;
	*) echo "Unknown target" ; exit 1 ;;
esac

trap restore EXIT

# Check the package exists in $FROM_RELEASE
apt-get source --simulate -t ${FROM_RELEASE} ${PACKAGE}
VERSION="$(LC_ALL=C apt-cache policy -t ${FROM_RELEASE} ${PACKAGE} | sed -n -r 's/.*Candidate: //p')"

if [ -z "${VERSION}" ]; then
	echo "${PACKAGE} is not available in ${FROM_RELEASE}"
	apt-cache policy "${PACKAGE}"
	exit 1
fi

prepare