Whatever the reason, one of the newest concepts (at least over the past 3 years or so) that has emerged as one of our heated topics of debate is how to manage object dependencies. Interestingly, the argument of how to manage dependencies is generally named by the solution which it's proponents give as the solution: dependency injection (the abstract principle is actually called Inversion of control).

He starts with simple examples - pushing an object into the creation of another - and backfills with a brief history of dependencies in PHP applications for a little context. He talks about DI frameworks like Spring and some of the other criticisms and thoughts you'll need to consider when using DI (and DI containers) during development and deployment.

When it comes to open source projects endorsing PHP 5.3 as their one and only PHP platform, I encourage caution. When it comes to open source projects that use PHP, there are three main issues that I believe should be considered before making the leap to PHP 5.3 (or any new release of any new software).

He sees three considerations projects and companies should consider before making the upgrade on their servers - the amount of control you have over the environment, deciding if the upgrade is worth possible backwards compatibility breaks and how much support you want to still provide for the pre-5.3 version(s).