Why to have "build/" folder with PHP project and phing

Question

What is a benefit of having "build/" folder where all the sources will be placed and "built"?

Maybe it's a silly question, but I'm trying to understand Continuous Integration with PHP. Any example of build.xml for phing uses such build/ folder, but what's a sense in that for PHP where a checked out project doesn't require a compilation, only a basic configuration. Copying it all into build/ will just complicate the things, because you'll have doubled files and +1 folder to the web root path (if you'd like to have web UI to run selenium tests on)

Particularly I need phing for two cases:
1) let new user setup his first installation (or update old), right on a working copy
2) run unit/func-tests, phpcc, phpcs, phpdoc etc (all that usually on CI server)

Should I have "build/" for the second task? What is the best practice for PHP?

Answer 1

There are several good reasons to have a build directory (i.e., deployment to multiple environments, performing some text replacement, minimizing and combining CSS and JS, optimizing images, handling of config files etc.)

However, these may not apply in your use cases. There is no rule saying you need this directory. Depending on your thinking on testing in production, a build directory may be a good reason to keep this directory.