Merge pull request #255 from ParsePlatform/nlutsenko.deleteAllEmpty

Fixed crash when using PFObject.deleteAll() with empty array.

Author: nlutsenko

Parse/PFObject.m

@@ -2432,10 +2432,10 @@ + (BOOL)deleteAll:(NSArray *)objects error:(NSError **)error {
     return [[[self deleteAllInBackground:objects] waitForResult:error] boolValue];
 }
 
-+ (BFTask *)deleteAllInBackground:(NSArray *)objects {
++ (BFTask PF_GENERIC(NSNumber *) *)deleteAllInBackground:(NSArray *)objects {
     NSArray *deleteObjects = [objects copy]; // Snapshot the objects.
     if (deleteObjects.count == 0) {
-        return [BFTask taskWithResult:objects];
+        return [BFTask PF_GENERIC(NSNumber *) taskWithResult:@YES];
     }
     return [[[[self currentUserController] getCurrentUserSessionTokenAsync] continueWithBlock:^id(BFTask *task) {
         NSString *sessionToken = task.result;

Tests/Unit/ObjectUnitTests.m

@@ -11,6 +11,7 @@
 #import "PFUnitTestCase.h"
 #import "Parse_Private.h"
 #import "PFObjectPrivate.h"
+#import "BFTask+Private.h"
 
 @interface ObjectUnitTests : PFUnitTestCase
 
@@ -199,6 +200,30 @@ - (void)testFetchObjectWithoutObjectIdError {
     [self waitForTestExpectations];
 }
 
+#pragma mark DeleteAll
+
+- (void)testDeleteAllWithoutObjects {
+    XCTAssertTrue([PFObject deleteAll:nil]);
+    XCTAssertTrue([PFObject deleteAll:@[]]);
+
+    NSError *error = nil;
+    XCTAssertTrue([PFObject deleteAll:nil error:&error]);
+    XCTAssertNil(error);
+    XCTAssertTrue([PFObject deleteAll:@[] error:&error]);
+    XCTAssertNil(error);
+
+    XCTAssertTrue([[[PFObject deleteAllInBackground:nil] waitForResult:nil] boolValue]);
+    XCTAssertTrue([[[PFObject deleteAllInBackground:@[]] waitForResult:nil] boolValue]);
+
+    XCTestExpectation *expectation = [self currentSelectorTestExpectation];
+    [PFObject deleteAllInBackground:nil block:^(BOOL succeeded, NSError * _Nullable error) {
+        XCTAssertTrue(succeeded);
+        XCTAssertNil(error);
+        [expectation fulfill];
+    }];
+    [self waitForTestExpectations];
+}
+
 #pragma mark Revert
 
 - (void)testRevert {