To avoid updating installPlugins() when installPlugin() is updated (and other way around), installPlugins() should use installPlugin():

public function installPlugins() {
foreach($this→getLoadedPlugins() as $plugin) {
try {
$this→installPlugin();
} catch(Exception $e) {
throw new Piwik_Plugin_Exception($plugin→getName(), $e→getMessage());
}
}
}
Keywords: plugins