Programming Pitfalls: Circular Imports in Objective-C

PitfallI spend a lot of time in XCode working in Objective-C for iOS and Mac OS X projects. In many ways, Objective-C has become my “native language” in terms of programming languages. Still, that doesn’t mean that I can’t make really silly mistakes when working in that language. In fact, through the magic of GitHub you can see the mistake in real-time in my open-source Cocoa / Cocoa Touch networking library, MDNetworking.

The mistake is, like the best dumb mistakes, small and simple but can take more time than I’d like to admit to notice and resolve. Take a look at this pseudo-code sample for what went wrong:

#import "Foo.h"
#import "Bar.h"

@implementation Foo
 // CODE
@end

 

#import "Bar.h"
#import "Foo.h"

@implementation Bar
// CODE
@end

That’s it. That’s all you need to do to reproduce this programming pitfall. As always, I hope this has been illuminating and entertaining for you and please do follow me on Twitter.