Fix FSTLocalDocumentsView to allow multiple mutations while offline (#644)

* Fix FSTLocalDocumentsView to allow multiple mutations while offline.

Previously, only the last mutation would actually be visible.

Author: rsgowman

Firestore/CHANGELOG.md

@@ -1,4 +1,4 @@
-# Unreleased (firestore-api-changes)
+# Unreleased
 - [changed] Removed the includeMetadataChanges property in FIRDocumentListenOptions
   to avoid confusion with the factory method of the same name.
 - [changed] Added a commit method that takes no completion handler to FIRWriteBatch.
@@ -13,6 +13,8 @@
   `true` if the SDK loses its connection to the backend. A new event with
   `snapshot.metadata.isFromCache` set to false will be raised once the
   connection is restored and the query is in sync with the backend again.
+- [fixed] Multiple offline mutations now properly reflected in retrieved
+  documents. Previously, only the last mutation would be visible. (#643)
 
 # v0.9.4
 - [changed] Firestore no longer has a direct dependency on FirebaseAuth.

Firestore/Example/Tests/Integration/API/FIRQueryTests.m

@@ -275,4 +275,27 @@ - (void)testQueriesFireFromCacheWhenOffline {
   [registration remove];
 }
 
+- (void)testCanHaveMultipleMutationsWhileOffline {
+  FIRCollectionReference *col = [self collectionRef];
+
+  // set a few docs to known values
+  NSDictionary *initialDocs =
+      @{ @"doc1" : @{@"key1" : @"value1"},
+         @"doc2" : @{@"key2" : @"value2"} };
+  [self writeAllDocuments:initialDocs toCollection:col];
+
+  // go offline for the rest of this test
+  [self disableNetwork];
+
+  // apply *multiple* mutations while offline
+  [[col documentWithPath:@"doc1"] setData:@{@"key1b" : @"value1b"}];
+  [[col documentWithPath:@"doc2"] setData:@{@"key2b" : @"value2b"}];
+
+  FIRQuerySnapshot *result = [self readDocumentSetForRef:col];
+  XCTAssertEqualObjects(FIRQuerySnapshotGetData(result), (@[
+                          @{@"key1b" : @"value1b"},
+                          @{@"key2b" : @"value2b"},
+                        ]));
+}
+
 @end

Firestore/Example/Tests/Util/FSTIntegrationTestCase.mm

@@ -18,14 +18,14 @@
 
 #import <FirebaseCore/FIRLogger.h>
 #import <FirebaseFirestore/FirebaseFirestore-umbrella.h>
-#import <Firestore/Source/Core/FSTFirestoreClient.h>
 #import <GRPCClient/GRPCCall+ChannelArg.h>
 #import <GRPCClient/GRPCCall+Tests.h>
 
 #include "Firestore/core/src/firebase/firestore/util/autoid.h"
 
 #import "Firestore/Source/API/FIRFirestore+Internal.h"
 #import "Firestore/Source/Auth/FSTEmptyCredentialsProvider.h"
+#import "Firestore/Source/Core/FSTFirestoreClient.h"
 #import "Firestore/Source/Local/FSTLevelDB.h"
 #import "Firestore/Source/Model/FSTDatabaseID.h"
 #import "Firestore/Source/Util/FSTDispatchQueue.h"

Firestore/Source/Local/FSTLocalDocumentsView.m

@@ -167,9 +167,9 @@ - (FSTDocumentDictionary *)localDocuments:(FSTDocumentDictionary *)documents {
                                                  BOOL *stop) {
     FSTMaybeDocument *mutatedDoc = [self localDocument:remoteDocument key:key];
     if ([mutatedDoc isKindOfClass:[FSTDeletedDocument class]]) {
-      result = [documents dictionaryByRemovingObjectForKey:key];
+      result = [result dictionaryByRemovingObjectForKey:key];
     } else if ([mutatedDoc isKindOfClass:[FSTDocument class]]) {
-      result = [documents dictionaryBySettingObject:(FSTDocument *)mutatedDoc forKey:key];
+      result = [result dictionaryBySettingObject:(FSTDocument *)mutatedDoc forKey:key];
     } else {
       FSTFail(@"Unknown document: %@", mutatedDoc);
     }