if (version == null && start instanceof RevTag)
version = ((RevTag) start).getTagName();
else if (version == null)
throw die(MessageFormat.format(CLIText.get().notATagVersionIsRequired, start.name()));
log.scan(db, rw.parseCommit(start), version);
if (output != null) {
if (!output.getParentFile().exists())
output.getParentFile().mkdirs();
LockFile lf = new LockFile(output, db.getFS());