phingofficial/phing — pull request #301 by shevron (2014-08-17 14:10:25+00:00)
Title: Bugfix: Phing exits silently, no error message when using JsMinTask and ...

...no composer installed

Honestly, I think that the use of '@' should be dropped, but in any case I'm pretty sure the intention here was to use include_once and not require_once, which just exits silently here and does not throw the wanted exception.