patchset-parse

#!/usr/bin/env bash

function fatal() {
	echo
	echo -e '[ERROR]>>' "$*" >&2
	exit 1
}

if [[ "$1" =~ ^(--help|-h)$ ]]; then
	# TODO: add help dialog
	fatal 'Not implemented'
fi

if ! [[ "$(git branch --show-current)" =~ change-.* ]]; then
	fatal 'You need to be checked out on a change branch to use this command'
elif [[ $# -le 1 ]]; then
	fatal 'No arguments given, just use the standard git command'
fi

# Parse 'cherry picked from' footer
git show --pretty=%b -s |
	sed '/^\s*$/d' |
	tac |
	grep -P '(?<=\s)[0-9a-f]{40}(?=\)$)' --only-matching |
	head -n 1 |
	xargs -I{} git rev-parse --verify {}~1 >"$(git rev-parse --git-dir)/BASE"

trap 'rm -rf "$(git rev-parse --git-dir)/BASE"' EXIT
patchset_regex="^(\^)?([1-9][0-9]*)((~|\^)[0-9]*)?(:.*)?$"

declare -i current_patchset
current_patchset=$(git rev-list --count HEAD ^BASE)
if [[ $current_patchset -le 0 ]]; then
	fatal 'Current_patchset parsed as non positive\n' \
		"Current patchset: $current_patchset"
fi

command="$1"
shift
declare -a args

while [[ $# -gt 0 ]]; do
	if grep -Eq "$patchset_regex" <<<"$1"; then
		declare -i patchset
		patchset="$(sed -E "s/$patchset_regex/\2/" <<<"$1")"

		patchset_ref="$(git rev-parse --verify HEAD~$((current_patchset - patchset)))"
		rev="$(sed -E "s/$patchset_regex/\1$patchset_ref\3\5/" <<<"$1")"
		args+=("$rev")

	elif [[ "$1" == "-n" ]]; then
		args+=("$1" "$2")
		shift

	else
		args+=("$1")
	fi
	shift
done
git "$command" "${args[@]}"