Question

Correct me if I’m wrong, but a ‘build’ is a ‘compile’, and not every language compiles. Continuous Integration involves building components to see if they continue to work beyond unit tests, which I might be oversimplifying. But if your project involves a language that does not compile, how do you perform nightly builds or use continuous integration techniques?

Answer 1

Hmm… I’d define ‘building’ as something like ‘preparing, packaging and deploying all artifacts of a software system’. The compilation to machine code is only one of many steps in the build. Others might be checking out the latest version of the code from scm-system, getting external dependencies, setting configuration values depending on the target the software gets deployed to and running some kind of test suite to ensure you’ve got a ‘working/running build’ before you actually deploy.

‘Building’ software can/must be done for any software, independent of your programming langugage. Intepreted languages have the ‘disadvantage’ that syntactic or structural (meaning e.g. calling a method with wrong parameters etc.) errors normally will only be detected at runtime (if you don’t have a separate step in your build which checks for such errors e.g. with PHPLint).

Thus (automated) Testcases (like Unit-Tests – see PHPUnit or SimpleTest – and Frontend-Tests – see Selenium) are all the more important for big PHP projects to ensure the good health of the code.

There’s a great Build-Tool (like Ant for Java or Rake for Ruby) for PHP too: Phing

CI-Systems like Xinc or Hudson are simply used to automagically (like anytime a change is checked into scm) package your code, check it for obvious errors, run your tests (in short: run your build) and report the results back to your development team.