#!/bin/sh
set -eu
set -o pipefail
dir="$1"
fallback="$2"
# Apparently git describe has a bug where it always considers the work-tree
# dirty when invoked with --git-dir (even though 'git status' is happy). Work
# around this issue by cd-ing to the source directory.
cd "$dir" && git describe --abbrev=7 --dirty=+ 2>/dev/null | sed 's/^v//' || echo "$fallback"
