+# This script can be sourced by the commit filter to get the functions
+test "a$SOURCE_FUNCTIONS" = a1 && return
+this_script="$(cd "$(dirname "$0")"; pwd)"/$(basename "$0")
+export this_script
+
+USAGE="[--env-filter <command>] [--tree-filter <command>] \
+[--index-filter <command>] [--parent-filter <command>] \
+[--msg-filter <command>] [--commit-filter <command>] \
+[--tag-name-filter <command>] [--subdirectory-filter <directory>] \
+[--original <namespace>] [-d <directory>] [-f | --force] \
+[<rev-list options>...]"
+
+. git-sh-setup
+
+git diff-files --quiet &&
+ git diff-index --cached --quiet HEAD ||
+ die "Cannot rewrite branch(es) with a dirty working directory."
+