When should I commit?

Question

Here is my setup -

Xcode 3.2.5 
Cornerstone 2.0
SVN server 1.6

I am using cornerstone for version control and nothing setting anything in xcode.

Now here is the scenario -

I am working in a team (We all decided to use SVN for our new project) of 5 programmers. Now when I add a new view controller (i.e. LoginViewController.m) on my system the .xcodeproj file gets changed immediately on my system.

Mean while another programmer also add one more view controller (SignupViewController.m). His .xcodeproj file also gets changed.

Now when I complete my code of LoginViewController I commit it. After some time the second programmer finish the SignupViewController and commits his work.

Now using the above procedure the .xcodeproj file gets corrupt and xcode won't open that project again.

Now my question is When should we commit our work when developing iPhone apps under xcode when using a third party svn client. Can someone please elaborate the process of when should we commit in cornerstone.

Should we commit the project just after when we add something in project (like files, images, music)?

It will be great if you can also provide me a tutorial on using xcode + cornerstone in real world.

Answer 1

Remember this:

Always update before you commit.

Answer 2

One way to do this:

Whenever you want to change something to the project structure (add a class for example), you first update your working copy, make the change, and commit right away. Of course that means you'll check in an empty class, but that's no big issue in most cases. If everyone follows that rule, you shouldn't have any problems.