Since all that really can be deferred from the dumped code is that someone made a typo in a globally included config file (whether it was outside of webroot or not can't really be determined). The obvious issue is that obviously there was no process for testing code prior to deployment. This could have been caught using a standard Dev/Stage/Production environment setup, or even a quick test prior to deployment to Production. Other possible ways to catch this is with proper Unit Testing (which would have broken when not a single service would work due to no config params coming through), or a proper Continuous Integration environment to handle all that.