diff-rpi-source

#!/bin/bash -eu
#
# Diff the current branch against the relevant raspberrypi branch
#

function usage()
{
	cat <<EOF
Usage: diff-rpi-source [-h] [-v] [TAG]

Diff the current branch against the relevant raspberrypi branch.

Postional arguments:
  TAG            Diff the current branch against tag TAG. If not provided,
                 determines the tag automatically.

Optional arguments:
  -h, --help     Show this help text and exit.
  -v, --verbose  Verbose output.
EOF
}

verbose=0
rpi_tag=

while [ ${#} -gt 0 ] ; do
	case "${1}" in
		-h|--help)
			usage
			exit
			;;
		-v|--verbose)
			verbose=1
			;;
		*)
			if [ -z "${rpi_tag}" ] ; then
				rpi_tag=${1}
			else
				echo "Invalid argument: ${1}" >&2
				exit 2
			fi
			;;
	esac
	shift
done

# Determine the 'start' of the derivative
master_version=$(dpkg-parsechangelog -l debian.master/changelog -S Version)
master_source=$(dpkg-parsechangelog -l debian.master/changelog -S Source)
master_source=${master_source#linux}
master_tag=Ubuntu${master_source}-${master_version}
tmp=$(git log --oneline -2000 | \
		  grep -m1 -P "^[0-9a-f]{12} UBUNTU: ${master_tag}$" || true)
master_commit=${tmp%% *}
if [ -z "${master_commit}" ] ; then
	echo "Failed to determine Ubuntu master commit: ${master_tag}" >&2
	exit 1
fi

# Determine the last raspberrypi update tag
if [ -z "${rpi_tag}" ] ; then
	tmp=$(git log --oneline -1000 | \
			  grep -m1 -P "^[0-9a-f]{12} UBUNTU:.* Update to upstream raspberrypi" || \
			  true)
	rpi_tag=${tmp#* upstream raspberrypi }
	rpi_tag=${rpi_tag%\)*}
	rpi_tag=${rpi_tag/ \(/-}
	if [ -z "${rpi_tag}" ] ; then
		echo "Failed to determine raspberrypi update tag" >&2
		exit 1
	fi
fi

if ! git rev-parse "${rpi_tag}" >/dev/null 2>&1 ; then
	echo "No such tag: ${rpi_tag}" >&2
	exit 1
fi

# Collect the list of modified files
while IFS= read -r name ; do
	git --no-pager diff --color=always "${rpi_tag}" -- "${name}" > .tmp || true
	if [ ${verbose} -eq 1 ] || [ -s .tmp ] ; then
		echo
		echo -e "\e[93m${name}\e[0m"
		cat .tmp
	fi
done < <(git log --format= --name-only "${master_commit}".. | \
			 grep -vP '^(debian|ubuntu|\.)' | sort -u)