Objective-C method returning a dictionary of Class crashes in Xcode 10.2

Question

I am facing a weird crash after updating the Xcode to 10.2. I have an Objective-C class method as below

@interface Car: NSObject 

+ (NSDictionary<NSString *, Class>  *) carMapping;

@end

which returns dictionary of type NSDictionary<NSString *, Class> as below

@implementation Car

+ (NSDictionary<NSString *, Class>  *) carMapping {
    return @{
        @"BMW": [BMWCar class],
        @"Mercedes": [MercedesCar class],
        @"Toyota": [ToyotaCar class],
        @"Tesla": [TeslaCar class]
        };
}

@end

I use this Objective-C method in Swift as

let carMapping = Car.carMapping()
print(carMapping)

which works perfectly fine with Xcode 10.1.

But after updating the Xcode to 10.2, app crashes saying Thread 1: EXC_BAD_ACCESS (code=1, address=0x0) in line 1. I do not have any clue.

I do not have control over the class Car. How would I handle the situation?

Actually that function signature says it returns a dictionary, not an array of dictionaries. You should post the body of your `carMapping()` method, along with the whole interface to your `Car` class. — Duncan C, Apr 02 '19 at 13:06
@DuncanC, Sorry! my bad while writing the question. Corrected — iOS, Apr 02 '19 at 13:09
How did you call carMapping in Objective-c? Did you clean the project and rebuild it? — E.Coms, Apr 02 '19 at 13:46
@E.Coms Yes. Tried everything I could do. I did not call carMapping in Objective C, I do that in a Swift class. — iOS, Apr 02 '19 at 13:57
That is still not an array of dictionaries. Your function returns a dictionary of type `[String: Class]`. — Duncan C, Apr 02 '19 at 16:49

score 1 · Accepted Answer · answered Apr 02 '19 at 14:35

If you want to use the class in swift without most hassles, just change the signature in the interface from Class to id. In the implementation, you don't need to change.

 @interface Car : NSObject
 + (NSDictionary<NSString *, id>  *) carMapping ;
 @end

Objective-C method returning a dictionary of Class crashes in Xcode 10.2

1 Answers1