Open Radar

 
Summary:
The C data type Union is not key value coding compliant.  Attempting to call setValue:ForKey: will crash and give the error "failed: caught "NSUnknownKeyException", "[<DUXOSBindClass 0x6000008258c0> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key testUnion.""

Steps to Reproduce:
The steps to reproduce just require attempting to call setValue:ForKey:  with a Union encoded into an NSValue.

typedef struct {
    CGFloat testFloat;
} DUXOSTestStruct;

typedef union {
    CGFloat testFloat;
} DUXOSTestUnion;


@interface DUXOSBindClass : NSObject

@property (assign, nonatomic) DUXOSTestStruct testStruct;
@property (assign, nonatomic) DUXOSTestUnion testUnion;

@end

@implementation DUXOSBindClass

- (instancetype)init {
    self = [super init];
    if (self) {
        DUXOSTestStruct exampleStruct = {0.0};
        self.testStruct = exampleStruct;
        
        DUXOSTestUnion exampleUnion = {0.0};
        self.testUnion = exampleUnion;
    }
    return self;
}

@end

@interface DUXOSRuntimeMappingCTests : XCTestCase

@property (strong, nonatomic) DUXOSBindClass *bindClass;

@end

@implementation DUXOSRuntimeMappingCTests

- (void)setUp {
    // Put setup code here. This method is called before the invocation of each test method in the class.
    self.bindClass = [DUXOSBindClass new];
}

- (void)tearDown {
    // Put teardown code here. This method is called after the invocation of each test method in the class.
    self.bindClass = nil;
}

- (void)testStruct {
    DUXOSTestStruct testStruct = {1.0};
    [self.bindClass setValue:[NSValue value:&testStruct withObjCType:@encode(DUXOSTestStruct)] forKey:@"testStruct"];
    XCTAssert(self.bindClass.testStruct.testFloat == 1.0);
}

- (void)testUnion {
    DUXOSTestUnion testUnion = {1.0};
    [self.bindClass setValue:[NSValue value:&testUnion withObjCType:@encode(DUXOSTestUnion)] forKey:@"testUnion"];
    XCTAssert(self.bindClass.testUnion.testFloat == 1.0);
}

@end


Expected Results:

The test for both the struct and the union should pass.

Actual Results:
The test for the struct passes but the test for the union crashes with error "failed: caught "NSUnknownKeyException", "[<DUXOSBindClass 0x6000008258c0> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key testUnion.""

Version/Build:
Xcode 10.2.1 /12.3

Configuration:
iOS 12.3 iPad Pro 12.9-inch 3rd generation simulator