I could not agree more on having a test suite and also building and improving the test suite with each bugfix. On my team it is required to first create a test case to reproduce the bug. I usually get dirty looks from developers when I say to do this mainly because the process can be tedious. However, it would be impossible to count the number of times that a “simple bug fix” turned out to uncover some more complex issues when taking the time to thoroughly and consistently reproduce the bug with a test case.

If your project doesn’t have any unit tests yet, that’s ok. When you fix a bug is a great time to start creating one. ;)

This is a great point, and it shows the need for something like CodeSniffer to help ferret out those issues. CodeSniffer would have picked that up right away. I recommend a post-commit hook that runs it, and emails errors to the team for correction (a PHP lint hook should run on the pre-commit side).

CodeSniffer comes with a bunch of attachments, but you can also write your own standards. It’s part of PEAR, so you can get it that way. http://pear.php.net/package/PHP_CodeSniffer/