#!/bin/sh
# changed -- diff against the merge-base
die() {
	echo "ERROR: $*" 1>&2
	exit 1
}

REPO=$(git rev-parse --show-toplevel 2>/dev/null)
BASE=${BASE:-main}
if [ -n "$REPO" ]; then
	MBASE="$(git merge-base origin/$BASE HEAD 2>/dev/null)"
	[ -z "$MBASE" ] && die "origin/$BASE doesn't exist; set \$BASE and try again"
	git diff "$@" "$MBASE"
else
	die "not in a git repo"
fi