Turn off designated initializer checking in Xcode

Question

I'm getting the compile error:

error: convenience initializer missing a 'self' call to another initializer [-Werror,-Wobjc-designated-initializers]

Compile-checked designated initializers might be a good thing, but if I don't want deal with that right now, how can I turn this off?

Answer 1

Method 1

In your project:

1. Edit the build settings for your target (⌘-1, select project, or cf. Apple docs).
2. Search for "Other warning flags".
3. Add -Wno-objc-designated-initializers.

You can also do some combination of this and -Wobjc-designated-initializers on a per file basis or with clang diagnostic pushes and pops (cf. @bandejapaisa's "Method 3" answer below).

Method 2

This method allows you to switch back and forth between Xcode 5 & 6, and also provides you a reminder to fix the designated initializer stuff.

For iOS development, put this in your .pch (precompiled header) file:

#ifdef __IPHONE_8_0
    // suppress these errors until we are ready to handle them
    #pragma message "Ignoring designated initializer warnings"
    #pragma clang diagnostic ignored "-Wobjc-designated-initializers"
#else
    // temporarily define an empty NS_DESIGNATED_INITIALIZER so we can use now,
    // will be ready for iOS8 SDK
    #define NS_DESIGNATED_INITIALIZER
#endif

The analog to __IPHONE_8_0 for OS X 10.10 is __MAC_10_10.

Why?

If you are interested in why these messages exist, you can check out this SO answer or these Apple docs.

Answer 2

Following on from Clay's answer..

Method 3

You might want to suppress the warning on one occurrence, not all of them:

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wobjc-designated-initializers"
- (instancetype) initWithCoder:(NSCoder *)coder {
    self = [super initWithCoder:coder];
    if (self) {
        // do whatever I was doing....
    }
    return self;
}
#pragma clang diagnostic pop

EDIT: However, I've only actually used this once myself. I find it the same amount (or a little more) effort just to do it properly if it's a single case. So flag up your constructor with NS_DESIGNATED_INITIALIZER. And if it then complains about the init method not being overridden add an init method to your header with NS_UNAVAILABLE.