Allowing field deletes using merge fields (#1389)

2 files changed, 101 insertions, 3 deletions

diff --git a/Firestore/Example/Tests/Integration/API/FIRDatabaseTests.mm b/Firestore/Example/Tests/Integration/API/FIRDatabaseTests.mm
index f8091c0..e048a40 100644
--- a/Firestore/Example/Tests/Integration/API/FIRDatabaseTests.mm
+++ b/Firestore/Example/Tests/Integration/API/FIRDatabaseTests.mm
@@ -162,8 +162,10 @@
   NSDictionary<NSString *, id> *initialData = @{
     @"updated" : @NO,
   };
-  NSDictionary<NSString *, id> *mergeData =
-      @{@"time" : [FIRFieldValue fieldValueForServerTimestamp]};
+  NSDictionary<NSString *, id> *mergeData = @{
+    @"time" : [FIRFieldValue fieldValueForServerTimestamp],
+    @"nested" : @{@"time" : [FIRFieldValue fieldValueForServerTimestamp]}
+  };
 
   [self writeDocumentRef:doc data:initialData];
 
@@ -182,6 +184,7 @@
   FIRDocumentSnapshot *document = [self readDocumentForRef:doc];
   XCTAssertEqual(document[@"updated"], @NO);
   XCTAssertTrue([document[@"time"] isKindOfClass:[FIRTimestamp class]]);
+  XCTAssertTrue([document[@"nested.time"] isKindOfClass:[FIRTimestamp class]]);
 }
 
 - (void)testCanDeleteFieldUsingMerge {
@@ -218,6 +221,81 @@
   XCTAssertNil(document[@"nested.foo"]);
 }
 
+- (void)testCanDeleteFieldUsingMergeFields {
+  FIRDocumentReference *doc = [[self.db collectionWithPath:@"rooms"] documentWithAutoID];
+
+  NSDictionary<NSString *, id> *initialData = @{
+    @"untouched" : @YES,
+    @"foo" : @"bar",
+    @"inner" : @{@"removed" : @YES, @"foo" : @"bar"},
+    @"nested" : @{@"untouched" : @YES, @"foo" : @"bar"}
+  };
+  NSDictionary<NSString *, id> *mergeData = @{
+    @"foo" : [FIRFieldValue fieldValueForDelete],
+    @"inner" : @{@"foo" : [FIRFieldValue fieldValueForDelete]},
+    @"nested" : @{
+      @"untouched" : [FIRFieldValue fieldValueForDelete],
+      @"foo" : [FIRFieldValue fieldValueForDelete]
+    }
+  };
+  NSDictionary<NSString *, id> *finalData =
+      @{ @"untouched" : @YES,
+         @"inner" : @{},
+         @"nested" : @{@"untouched" : @YES} };
+
+  [self writeDocumentRef:doc data:initialData];
+
+  XCTestExpectation *completed =
+      [self expectationWithDescription:@"testCanMergeDataWithAnExistingDocumentUsingSet"];
+
+  [doc setData:mergeData
+      mergeFields:@[ @"foo", @"inner", @"nested.foo" ]
+       completion:^(NSError *error) {
+         XCTAssertNil(error);
+         [completed fulfill];
+       }];
+
+  [self awaitExpectations];
+
+  FIRDocumentSnapshot *document = [self readDocumentForRef:doc];
+  XCTAssertEqualObjects([document data], finalData);
+}
+
+- (void)testCanSetServerTimestampsUsingMergeFields {
+  FIRDocumentReference *doc = [[self.db collectionWithPath:@"rooms"] documentWithAutoID];
+
+  NSDictionary<NSString *, id> *initialData = @{
+    @"untouched" : @YES,
+    @"foo" : @"bar",
+    @"nested" : @{@"untouched" : @YES, @"foo" : @"bar"}
+  };
+  NSDictionary<NSString *, id> *mergeData = @{
+    @"foo" : [FIRFieldValue fieldValueForServerTimestamp],
+    @"inner" : @{@"foo" : [FIRFieldValue fieldValueForServerTimestamp]},
+    @"nested" : @{@"foo" : [FIRFieldValue fieldValueForServerTimestamp]}
+  };
+
+  [self writeDocumentRef:doc data:initialData];
+
+  XCTestExpectation *completed =
+      [self expectationWithDescription:@"testCanMergeDataWithAnExistingDocumentUsingSet"];
+
+  [doc setData:mergeData
+      mergeFields:@[ @"foo", @"inner", @"nested.foo" ]
+       completion:^(NSError *error) {
+         XCTAssertNil(error);
+         [completed fulfill];
+       }];
+
+  [self awaitExpectations];
+
+  FIRDocumentSnapshot *document = [self readDocumentForRef:doc];
+  XCTAssertTrue([document exists]);
+  XCTAssertTrue([document[@"foo"] isKindOfClass:[FIRTimestamp class]]);
+  XCTAssertTrue([document[@"inner.foo"] isKindOfClass:[FIRTimestamp class]]);
+  XCTAssertTrue([document[@"nested.foo"] isKindOfClass:[FIRTimestamp class]]);
+}
+
 - (void)testMergeReplacesArrays {
   FIRDocumentReference *doc = [[self.db collectionWithPath:@"rooms"] documentWithAutoID];
 
diff --git a/Firestore/Source/API/FSTUserDataConverter.mm b/Firestore/Source/API/FSTUserDataConverter.mm
index d73a870..d3e339d 100644
--- a/Firestore/Source/API/FSTUserDataConverter.mm
+++ b/Firestore/Source/API/FSTUserDataConverter.mm
@@ -218,6 +218,9 @@ typedef NS_ENUM(NSInteger, FSTUserDataSource) {
 /** Returns true for the non-query parse contexts (Set, MergeSet and Update) */
 - (BOOL)isWrite;
 
+/** Returns 'YES' if 'fieldPath' was traversed when creating this context. */
+- (BOOL)containsFieldPath:(const FieldPath &)fieldPath;
+
 - (const FieldPath *)path;
 
 - (const std::vector<FieldPath> *)fieldMask;
@@ -331,6 +334,22 @@ typedef NS_ENUM(NSInteger, FSTUserDataSource) {
   }
 }
 
+- (BOOL)containsFieldPath:(const FieldPath &)fieldPath {
+  for (const FieldPath &field : *_fieldMask) {
+    if (fieldPath.IsPrefixOf(field)) {
+      return YES;
+    }
+  }
+
+  for (const FieldTransform &fieldTransform : *_fieldTransforms) {
+    if (fieldPath.IsPrefixOf(fieldTransform.path())) {
+      return YES;
+    }
+  }
+
+  return NO;
+}
+
 - (void)validatePath {
   // TODO(b/34871131): Remove nil check once we have proper paths for fields within arrays.
   if (_path == nullptr) {
@@ -444,7 +463,8 @@ typedef NS_ENUM(NSInteger, FSTUserDataSource) {
             @"All elements in mergeFields: must be NSStrings or FIRFieldPaths.");
       }
 
-      if ([updateData valueForPath:path] == nil) {
+      // Verify that all elements specified in the field mask are part of the parsed context.
+      if (![context containsFieldPath:path]) {
         FSTThrowInvalidArgument(
             @"Field '%s' is specified in your field mask but missing from your input data.",
             path.CanonicalString().c_str());