Why printing config array gives empty Array?

[lnt]

$tpl = new Smarty();
$tpl->configLoad('compose.conf');
$config = $tpl->getConfigVars();
print_r($config);

it returns

Array()

[barryo]

The description for this repo states:

Clone of the distribution trunk of the PHP Smarty templating engine. Sync'd hourly by our servers.

I.e., this is a clone. A pure clone.