Example of how you can ensure you have programmatic encapsulation and capture of all SilverStripe generated errors.

silverstripe-exceptions.php

<?php

/**
 * SilverStripe doesn't typically use exceptions, but we may still need a programmatic method of encapsulating code
 * and catching errors. Here we can wrap code in a callback which will trigger an exception instead of user_error()'s.
 *
 * @param	callable	$closure
 * @throws	Exception
 */
function withExceptions(callable $closure) {
	// Override generic error handler with our own so that we can throw an exception instead.
	set_error_handler(function($errno , $errstr) {
		throw new Exception($errstr, $errno);
	});

	// Call passed closure.
	$e = null;
	try {
		call_user_func($closure);
	} catch(Exception $e) {}

	// Revert back to previous error handling.
	restore_error_handler();

	// If an exception occurred, go ahead and throw it now (in lieu of 'finally' available in PHP 5.5 and above).
	if ($e) throw $e;
}