PHP define is not working sometimes on some servers

Question

I am working on a PHP web app with another developer. We have 3 total different environments:

Configuration 1: Windows XAMPP, PHP 5.3.5
Configuration 2: Turnkey LAMP, PHP 5.3.X (turnkey-lamp-11.2-lucid-x86) - not sure which ver, running from virtualbox on a mac
Configuration 3: production server, hostgator shared running CentOS, php 5.3.9 fastcgi

Configuration 2 sometimes will not recognize the defines that are handled in our settings.php file which is require_once at the top of any page which uses it. The defines work fine on Configuration 1 and 3 always. There was nothing of interest in the apache logs, other than the errors generated as a result of the define being treated as a string.

I've searched for a while and cannot find anything that describes this issue. Configuration 2 is the other developer, and i do not have access to his machine right now. Looking for suggestions on how to track this issue down. I think we are going to try a new instance of the VM, using an upgraded turnkey-lamp, however i'd really like to root cause this.

Answer 1

Ok, so i figured out what was happening... and as expected, it wasn't PHP or defines. The errors reported were accurrate. We use Eclipse as the IDE, and Subclipse for SVN. Configuration 2 uses a VM running from a mac, and we added a command in eclipse to sync when files are saved. Apparently the syncing only was happening for the main public_html directory, and not our other same-level directory which has the include file with the defines in it. Ultimately, i needed to look at the actual VM to notice it was way out of date on that one file, and was missing the define statement, which results in the error, but Eclipse was showing the HEAD revision from SVN, which is why it was so confusing, but simple.

Lesson: Make sure you plugged in the TV before calling the repairman.