Issue #523 (Unimplemented, Unmapped, Optional Protocol Properties cra…

…sh MTLModel -validate:). Unimplemented, unmapped, optional protocol properties return MTLStoragePropertyNone from MTLModel +storageBehaviorForPropertyWithKeys:

Mantle/MTLModel.m

@@ -230,8 +230,12 @@ + (MTLPropertyStorage)storageBehaviorForPropertyWithKey:(NSString *)propertyKey
 	@onExit {
 		free(attributes);
 	};
-
-	if (attributes->readonly && attributes->ivar == NULL) {
+
+	Method getterMethod = class_getInstanceMethod(self.class, attributes->getter);
+	Method setterMethod = class_getInstanceMethod(self.class, attributes->setter);
+	if (!attributes->dynamic && attributes->ivar == NULL && getterMethod == NULL && setterMethod == NULL) {
+		return MTLPropertyStorageNone;
+	} else if (attributes->readonly && attributes->ivar == NULL) {
 		return MTLPropertyStorageNone;
 	} else {
 		return MTLPropertyStoragePermanent;

MantleTests/MTLModelSpec.m

@@ -190,4 +190,9 @@
 	});
 });
 
+it(@"should ignore optional protocol properties not implemented", ^{
+	expect(@([MTLOptionalPropertyModel storageBehaviorForPropertyWithKey:@"optionalProperty"])).to(equal(@(MTLPropertyStorageNone)));
+});
+
+
 QuickSpecEnd

MantleTests/MTLTestModel.h

@@ -154,3 +154,15 @@ extern const NSInteger MTLTestModelNameMissing;
 @property (readwrite, nonatomic, assign) NSUInteger freshness;
 
 @end
+
+
+@protocol MTLOptionalPropertyProtocol
+
+@optional
+@property (readwrite, nonatomic, copy) NSString *optionalProperty;
+
+@end
+
+@interface MTLOptionalPropertyModel : MTLModel <MTLOptionalPropertyProtocol>
+
+@end

MantleTests/MTLTestModel.m

@@ -462,3 +462,7 @@ - (NSString *)flavor {
 }
 
 @end
+
+@implementation MTLOptionalPropertyModel
+
+@end