Let the iOS SDK handle Delete ops when sent from the server

Parse/Internal/Object/State/PFObjectState.m

@@ -15,6 +15,7 @@
 #import "PFMutableObjectState.h"
 #import "PFObjectConstants.h"
 #import "PFObjectUtilities.h"
+#import "PFFieldOperation.h"
 
 @implementation PFObjectState
 
@@ -129,7 +130,11 @@ - (NSDictionary *)dictionaryRepresentationWithObjectEncoder:(PFEncoder *)objectE
 #pragma mark Accessors
 
 - (void)setServerDataObject:(id)object forKey:(NSString *)key {
-    _serverData[key] = object;
+    if (!object || [object isKindOfClass:[PFDeleteOperation class]]) {
+        [self removeServerDataObjectForKey:key];
+    } else {
+        _serverData[key] = object;
+    }
 }
 
 - (void)removeServerDataObjectForKey:(NSString *)key {

Tests/Unit/DecoderTests.m

@@ -45,6 +45,17 @@ - (void)testDecodingFieldOperations {
     XCTAssertEqualObjects(operation.amount, @100500);
 }
 
+- (void)testDecodingDeleteOperation {
+    PFDecoder *decoder = [[PFDecoder alloc] init];
+
+    NSDictionary *decoded = [decoder decodeObject:@{ @"key" : @{@"__op" : @"Delete"} }];
+    XCTAssertNotNil(decoded);
+
+    id operation = decoded[@"key"];
+    XCTAssertNotNil(operation);
+    PFAssertIsKindOfClass(operation, [PFDeleteOperation class]);
+}
+
 - (void)testDecodingDates {
     PFDecoder *decoder = [[PFDecoder alloc] init];
 

Tests/Unit/ObjectStateTests.m

@@ -166,6 +166,17 @@ - (void)testServerData {
     XCTAssertEqualObjects(mutableState.serverData, @{ @"foo": @"bar" });
 }
 
+- (void)testDeleteFromServerData {
+    PFMutableObjectState *mutableState = [[PFMutableObjectState alloc] init];
+    XCTAssertEqualObjects(mutableState.serverData, @{});
+
+    [mutableState setServerDataObject:@"foo" forKey:@"bar"];
+    XCTAssertEqualObjects(mutableState.serverData, @{ @"bar": @"foo" });
+
+    [mutableState setServerDataObject:[PFDeleteOperation new] forKey:@"bar"];
+    XCTAssertEqualObjects(mutableState.serverData, @{});
+}
+
 - (void)testEncode {
     PFMutableObjectState *mutableState = [[PFMutableObjectState alloc] init];
     mutableState.objectId = @"objectId";