gistfile1.php

Warning: call_user_func_array() expects parameter 1 to be a valid callback, array must have exactly two members in /wp-includes/plugin.php on line 429

pass-vars-to-action.php

<?php

final class Theme {
//...
	private function _declare_dependencies()
	{
		if(!class_exists('GFForms'))
		{
			add_action('admin_notices', array_map(array($this, 'dependency_missing'), array('Gravity Forms')));
		}
	}
//..
}

?>

Fundamentally my code wasn't even working.

It only looked like it did because the array_map was calling the function -- duh.

The return was an array -- which is not a callable function -- which produced the error.

So I needed to break it out into simpler actions -- utilizing do_action and remove_action later so it isn't called twice.