On the SitePoint PHP blog there's a post from Claudio Ribeiro introducing you to a new static analysis tool to help improve the quality of your code - PHP Static Analyzer, or "PHPSA" for short.
One requirement that never changes whether you are working on your projects alone or in a team, on small projects or big, is Code Quality. The bigger the project and the team, the harder it gets to maintain it.
A good way of slowing this increase in difficulty down is to use static analysis tools. Static analysis is the process of analyzing software without actually executing the program – a sort of automatic code review. Static analysis tools will detect common errors, enforce coding standards, and even clean up code blocks. The days of php -l filename are not over, but we now have a number of great tools that go the extra mile in helping us create and maintain high quality code.
They start with an example of using the tried and true "php -l" to lint an example PHP file but note that the yes/no answer it provides doesn't help give much feedback on the quality of the code, just its syntax. Enter PHPSA, a Composer-installable tool that does much more than lint checking. It also provides information about things like missing docblocks, function alias use and undefined property usage. they show an example of it in use on the command line, the results it provides and the changes made to the example class to fix the issues it found.