Generate debian/ and the .orig tarball from a packaging branch

build-deb-prepare

#!/bin/bash

: "${PACKAGING_BRANCH:=ubuntu/devel}"
: "${RELEASE:=UNRELEASED}"
: "${CLOGVER_DEBIAN:=0ubuntu1}"
: "${DEBFULLNAME:=$(git config user.name)}"
: "${DEBEMAIL:=$(git config user.email)}"

export DEBFULLNAME DEBEMAIL

fail() { echo "$@" 1>&2; exit 1; }

if [[ "$1" = "-h" || "$1" = "--help" ]]; then
    cat <<-EOF
	Usage: ${0##*/}

	Prepare the source for building a .deb package via e.g. debuild(1).

	Build a debian/ directory the current git HEAD pulling the debian/
	directory from branch '$PACKAGING_BRANCH' and updating the changelog,
	then prepare an .orig tarball matching the new changelog entry.
	EOF
    exit
fi

git clean -f debian || fail "Failed to run git clean."

# This script could work even if a debian/ directory is already existing,
# but it's a confusing setup that should be avoided.
[[ ! -e debian ]] || fail "A debian/ directory already exists."

[[ $DEBFULLNAME ]] || fail "Must have DEBFULLNAME or git user.name set."
[[ $DEBEMAIL ]] || fail "Must have DEBEMAIL or git user.email set."

if [[ $(git status -s) ]]; then
    cat 1>&2 <<-EOF
	WARNING: There are uncommitted changes in your working directory.
	         These changes will not be included in the orig archive.
	EOF
fi

# git describe will output something either like '0.1.0' (a tag)
# or TAG-N-gHASH where N is number of commits since TAG
uver=$(git describe --abbrev=8) ||
    fail "Failed to get upstream version with 'git describe'."
clogver_new="${uver}-${CLOGVER_DEBIAN}"

git restore --source="$PACKAGING_BRANCH" debian ||
    fail "Failed to get debian/ from '$PACKAGING_BRANCH'."
dch --newversion "$clogver_new" --distribution="$RELEASE" "Upstream build." ||
    fail "Failed to update d/changelog."
git deborig --force HEAD ||
    fail "Failed to generate the orig tarball."