protected static String[] getOldCommitUrns( File target ) throws IOException {
		if( !target.exists() ) return EMPTY_STRING_ARRAY;
		File commitListFile = commitListFile( target );
		if( !commitListFile.exists() ) return EMPTY_STRING_ARRAY;
		ArrayList<String> urns = new ArrayList<String>();
		BufferedReader r = new BufferedReader(new FileReader( commitListFile ));
		try {
			for( String l; (l = r.readLine()) != null; ) {
				l = l.trim();
				if( l.length() == 0 || l.startsWith("#") ) continue;
				urns.add(l);
			}
		} finally {
			r.close();
		}
		return urns.toArray(new String[urns.size()]);
	}