Diff ABT Experiments for real-time RC

FirebaseRemoteConfig/Sources/RCNConfigContent.h

@@ -66,6 +66,8 @@ typedef NS_ENUM(NSInteger, RCNDBSource) {
 - (NSDictionary *)getConfigAndMetadataForNamespace:(NSString *)FIRNamespace;
 
 /// Returns the updated parameters between fetched and active config.
-- (FIRRemoteConfigUpdate *)getConfigUpdateForNamespace:(NSString *)FIRNamespace;
+- (FIRRemoteConfigUpdate *)getConfigUpdateForNamespace:(NSString *)FIRNamespace
+                                 withExperimentChanges:
+                                     (NSMutableSet<NSString *> *)changedExperimentKeys;
 
 @end

FirebaseRemoteConfig/Sources/RCNConfigContent.m

@@ -399,11 +399,12 @@ - (BOOL)checkAndWaitForInitialDatabaseLoad {
 }
 
 // Compare fetched config with active config and output what has changed
-- (FIRRemoteConfigUpdate *)getConfigUpdateForNamespace:(NSString *)FIRNamespace {
-  // TODO: handle diff in experiment metadata
-
+- (FIRRemoteConfigUpdate *)getConfigUpdateForNamespace:(NSString *)FIRNamespace
+                                 withExperimentChanges:
+                                     (NSMutableSet<NSString *> *)changedExperimentKeys {
   FIRRemoteConfigUpdate *configUpdate;
   NSMutableSet<NSString *> *updatedKeys = [[NSMutableSet alloc] init];
+  updatedKeys = [[updatedKeys setByAddingObjectsFromSet:changedExperimentKeys] mutableCopy];
 
   NSDictionary *fetchedConfig =
       _fetchedConfig[FIRNamespace] ? _fetchedConfig[FIRNamespace] : [[NSDictionary alloc] init];

FirebaseRemoteConfig/Sources/RCNConfigExperiment.h

@@ -35,4 +35,7 @@
 
 /// Update experiments to Firebase Analytics when `activateWithCompletion:` happens.
 - (void)updateExperimentsWithHandler:(nullable void (^)(NSError *_Nullable error))handler;
+
+/// Return config keys from experiments that have changed.
+- (NSMutableSet<NSString *> *_Nonnull)getKeysAffectedByChangedExperiments;
 @end

FirebaseRemoteConfig/Sources/RCNConfigExperiment.m

@@ -27,6 +27,8 @@
 static NSString *const kMethodNameLatestStartTime =
     @"latestExperimentStartTimestampBetweenTimestamp:andPayloads:";
 
+static NSString *const kAffectedParameterKeys = @"affectedParameterKeys";
+
 @interface RCNConfigExperiment ()
 @property(nonatomic, strong)
     NSMutableArray<NSData *> *experimentPayloads;  ///< Experiment payloads.
@@ -197,4 +199,70 @@ - (NSTimeInterval)latestStartTimeWithExistingLastStartTime:(NSTimeInterval)exist
       latestExperimentStartTimestampBetweenTimestamp:existingLastStartTime
                                          andPayloads:_experimentPayloads];
 }
+
+/// Creates a map where the key is the config key and the value if the experiment description.
+- (NSMutableDictionary *)createExperimentsMap:(NSMutableArray<NSData *> *)experiments {
+  NSMutableDictionary<NSString *, NSMutableDictionary *> *experimentsMap =
+      [[NSMutableDictionary alloc] init];
+
+  /// Iterate through all the experiments and check if they contain `affectedParameterKeys`.
+  for (NSData *experiment in experiments) {
+    NSError *error;
+    NSDictionary *experimentJSON =
+        [NSJSONSerialization JSONObjectWithData:experiment
+                                        options:NSJSONReadingMutableContainers
+                                          error:&error];
+    if (!error && experimentJSON) {
+      if ([experimentJSON objectForKey:kAffectedParameterKeys]) {
+        NSMutableArray *configKeys =
+            (NSMutableArray *)[experimentJSON objectForKey:kAffectedParameterKeys];
+        NSMutableDictionary *experimentCopy = [experimentJSON mutableCopy];
+        /// Remove `affectedParameterKeys` because the values come out of order and could affect the
+        /// diffing.
+        [experimentCopy removeObjectForKey:kAffectedParameterKeys];
+
+        /// Map experiments to config keys.
+        for (NSString *key in configKeys) {
+          [experimentsMap setObject:experimentCopy forKey:key];
+        }
+      }
+    }
+  }
+
+  return experimentsMap;
+}
+
+/// Returns keys that were affected by experiment changes.
+- (NSMutableSet<NSString *> *)getKeysAffectedByChangedExperiments {
+  NSMutableSet<NSString *> *changedKeys = [[NSMutableSet alloc] init];
+  /// Create config keys to experiments map.
+  NSMutableDictionary *activeExperimentsMap = [self createExperimentsMap:_activeExperimentPayloads];
+  NSMutableDictionary *fetchedExperimentsMap = [self createExperimentsMap:_experimentPayloads];
+
+  /// Iterate through active experiment's keys and compare them to fetched experiment's keys.
+  for (NSString *key in [activeExperimentsMap allKeys]) {
+    if (![fetchedExperimentsMap objectForKey:key]) {
+      [changedKeys addObject:key];
+    } else {
+      if (![[activeExperimentsMap objectForKey:key]
+              isEqualToDictionary:[fetchedExperimentsMap objectForKey:key]]) {
+        [changedKeys addObject:key];
+      }
+    }
+  }
+
+  /// Iterate through fetched experiment's keys and compare them to active experiment's keys.
+  for (NSString *key in [fetchedExperimentsMap allKeys]) {
+    if (![activeExperimentsMap objectForKey:key]) {
+      [changedKeys addObject:key];
+    } else {
+      if (![[fetchedExperimentsMap objectForKey:key]
+              isEqualToDictionary:[activeExperimentsMap objectForKey:key]]) {
+        [changedKeys addObject:key];
+      }
+    }
+  }
+
+  return changedKeys;
+}
 @end

FirebaseRemoteConfig/Sources/RCNConfigFetch.m

@@ -216,8 +216,9 @@ - (void)realtimeFetchConfigWithNoExpirationDuration:(NSInteger)fetchAttemptNumbe
       if (strongSelf->_settings.lastFetchTimeInterval > 0) {
         FIRLogDebug(kFIRLoggerRemoteConfig, @"I-RCN000052",
                     @"A fetch is already in progress. Using previous fetch results.");
-        FIRRemoteConfigUpdate *update =
-            [self->_content getConfigUpdateForNamespace:self->_FIRNamespace];
+        FIRRemoteConfigUpdate *update = [self->_content
+            getConfigUpdateForNamespace:self->_FIRNamespace
+                  withExperimentChanges:[self->_experiment getKeysAffectedByChangedExperiments]];
         return [strongSelf reportCompletionWithStatus:strongSelf->_settings.lastFetchStatus
                                            withUpdate:update
                                             withError:nil
@@ -537,8 +538,9 @@ - (void)fetchWithUserProperties:(NSDictionary *)userProperties
       if (!data) {
         FIRLogInfo(kFIRLoggerRemoteConfig, @"I-RCN000043", @"RCN Fetch: No data in fetch response");
         // There may still be a difference between fetched and active config
-        FIRRemoteConfigUpdate *update =
-            [strongSelf->_content getConfigUpdateForNamespace:strongSelf->_FIRNamespace];
+        FIRRemoteConfigUpdate *update = [strongSelf->_content
+            getConfigUpdateForNamespace:strongSelf->_FIRNamespace
+                  withExperimentChanges:[self->_experiment getKeysAffectedByChangedExperiments]];
         return [strongSelf reportCompletionWithStatus:FIRRemoteConfigFetchStatusSuccess
                                            withUpdate:update
                                             withError:nil
@@ -615,8 +617,9 @@ - (void)fetchWithUserProperties:(NSDictionary *)userProperties
         strongSelf->_settings.lastETag = latestETag;
       }
       // Compute config update after successful fetch
-      FIRRemoteConfigUpdate *update =
-          [strongSelf->_content getConfigUpdateForNamespace:strongSelf->_FIRNamespace];
+      FIRRemoteConfigUpdate *update = [strongSelf->_content
+          getConfigUpdateForNamespace:strongSelf->_FIRNamespace
+                withExperimentChanges:[self->_experiment getKeysAffectedByChangedExperiments]];
 
       [strongSelf->_settings
           updateMetadataWithFetchSuccessStatus:YES

FirebaseRemoteConfig/Tests/Unit/RCNConfigContentTest.m

@@ -344,11 +344,39 @@ - (void)testConfigUpdate_noChange_emptyResponse {
                             toSource:RCNDBSourceActive
                         forNamespace:namespace];
 
-  FIRRemoteConfigUpdate *update = [_configContent getConfigUpdateForNamespace:namespace];
+  FIRRemoteConfigUpdate *update =
+      [_configContent getConfigUpdateForNamespace:namespace
+                            withExperimentChanges:[[NSMutableSet alloc] init]];
 
   XCTAssertTrue([update updatedKeys].count == 0);
 }
 
+- (void)testConfigUpdate_noParamChange_butExperimentChange {
+  NSString *namespace = @"test_namespace";
+
+  // populate fetched config
+  NSMutableDictionary *fetchResponse =
+      [self createFetchResponseWithConfigEntries:@{@"key1" : @"value1"} p13nMetadata:nil];
+  [_configContent updateConfigContentWithResponse:fetchResponse forNamespace:namespace];
+
+  // active config is the same as fetched config
+  FIRRemoteConfigValue *value =
+      [[FIRRemoteConfigValue alloc] initWithData:[@"value1" dataUsingEncoding:NSUTF8StringEncoding]
+                                          source:FIRRemoteConfigSourceRemote];
+  NSDictionary *namespaceToConfig = @{namespace : @{@"key1" : value}};
+  [_configContent copyFromDictionary:namespaceToConfig
+                            toSource:RCNDBSourceActive
+                        forNamespace:namespace];
+
+  NSMutableSet *experimentKeys = [[NSMutableSet alloc] init];
+  [experimentKeys addObject:@"key_2"];
+  FIRRemoteConfigUpdate *update = [_configContent getConfigUpdateForNamespace:namespace
+                                                        withExperimentChanges:experimentKeys];
+
+  XCTAssertTrue([update updatedKeys].count == 1);
+  XCTAssertTrue([[update updatedKeys] containsObject:@"key_2"]);
+}
+
 - (void)testConfigUpdate_paramAdded_returnsNewKey {
   NSString *namespace = @"test_namespace";
   NSString *newParam = @"key2";
@@ -368,7 +396,9 @@ - (void)testConfigUpdate_paramAdded_returnsNewKey {
                                     p13nMetadata:nil];
   [_configContent updateConfigContentWithResponse:fetchResponse forNamespace:namespace];
 
-  FIRRemoteConfigUpdate *update = [_configContent getConfigUpdateForNamespace:namespace];
+  FIRRemoteConfigUpdate *update =
+      [_configContent getConfigUpdateForNamespace:namespace
+                            withExperimentChanges:[[NSMutableSet alloc] init]];
 
   XCTAssertTrue([update updatedKeys].count == 1);
   XCTAssertTrue([[update updatedKeys] containsObject:newParam]);
@@ -394,7 +424,9 @@ - (void)testConfigUpdate_paramValueChanged_returnsUpdatedKey {
       [self createFetchResponseWithConfigEntries:@{existingParam : updatedValue} p13nMetadata:nil];
   [_configContent updateConfigContentWithResponse:fetchResponse forNamespace:namespace];
 
-  FIRRemoteConfigUpdate *update = [_configContent getConfigUpdateForNamespace:namespace];
+  FIRRemoteConfigUpdate *update =
+      [_configContent getConfigUpdateForNamespace:namespace
+                            withExperimentChanges:[[NSMutableSet alloc] init]];
 
   XCTAssertTrue([update updatedKeys].count == 1);
   XCTAssertTrue([[update updatedKeys] containsObject:existingParam]);
@@ -420,7 +452,9 @@ - (void)testConfigUpdate_paramDeleted_returnsDeletedKey {
       [self createFetchResponseWithConfigEntries:@{newParam : value1} p13nMetadata:nil];
   [_configContent updateConfigContentWithResponse:fetchResponse forNamespace:namespace];
 
-  FIRRemoteConfigUpdate *update = [_configContent getConfigUpdateForNamespace:namespace];
+  FIRRemoteConfigUpdate *update =
+      [_configContent getConfigUpdateForNamespace:namespace
+                            withExperimentChanges:[[NSMutableSet alloc] init]];
 
   XCTAssertTrue([update updatedKeys].count == 2);
   XCTAssertTrue([[update updatedKeys] containsObject:existingParam]);  // deleted
@@ -455,7 +489,9 @@ - (void)testConfigUpdate_p13nMetadataUpdated_returnsKey {
                    forKey:RCNFetchResponseKeyPersonalizationMetadata];
   [_configContent updateConfigContentWithResponse:fetchResponse forNamespace:namespace];
 
-  FIRRemoteConfigUpdate *update = [_configContent getConfigUpdateForNamespace:namespace];
+  FIRRemoteConfigUpdate *update =
+      [_configContent getConfigUpdateForNamespace:namespace
+                            withExperimentChanges:[[NSMutableSet alloc] init]];
 
   XCTAssertTrue([update updatedKeys].count == 1);
   XCTAssertTrue([[update updatedKeys] containsObject:existingParam]);
@@ -480,7 +516,9 @@ - (void)testConfigUpdate_valueSourceChanged_returnsKey {
       [self createFetchResponseWithConfigEntries:@{existingParam : value1} p13nMetadata:nil];
   [_configContent updateConfigContentWithResponse:fetchResponse forNamespace:namespace];
 
-  FIRRemoteConfigUpdate *update = [_configContent getConfigUpdateForNamespace:namespace];
+  FIRRemoteConfigUpdate *update =
+      [_configContent getConfigUpdateForNamespace:namespace
+                            withExperimentChanges:[[NSMutableSet alloc] init]];
 
   XCTAssertTrue([update updatedKeys].count == 1);
   XCTAssertTrue([[update updatedKeys] containsObject:existingParam]);

FirebaseRemoteConfig/Tests/Unit/RCNConfigExperimentTest.m

@@ -43,6 +43,7 @@ @interface RCNConfigExperiment ()
 - (NSTimeInterval)updateExperimentStartTime;
 - (void)loadExperimentFromTable;
 - (void)updateActiveExperimentsInDB;
+- (NSMutableSet<NSString *> *_Nonnull)getKeysAffectedByChangedExperiments;
 @end
 
 @interface RCNConfigExperimentTest : XCTestCase {
@@ -239,6 +240,119 @@ - (void)testUpdateExperiments {
   }];
 }
 
+- (void)testExperimentDiff_addedExperiment {
+  FIRExperimentController *experimentController =
+      [[FIRExperimentController alloc] initWithAnalytics:nil];
+  id mockExperimentController = OCMPartialMock(experimentController);
+  RCNConfigExperiment *experiment =
+      [[RCNConfigExperiment alloc] initWithDBManager:_DBManagerMock
+                                experimentController:mockExperimentController];
+
+  NSData *payloadData1 = [[self class] payloadDataFromTestFile];
+  experiment.activeExperimentPayloads = [@[ payloadData1 ] mutableCopy];
+
+  NSError *dataError;
+  NSMutableDictionary *payload =
+      [NSJSONSerialization JSONObjectWithData:payloadData1
+                                      options:NSJSONReadingMutableContainers
+                                        error:&dataError];
+  [payload setValue:@"exp_2" forKey:@"experimentId"];
+  NSError *jsonError;
+  NSData *payloadData2 = [NSJSONSerialization dataWithJSONObject:payload
+                                                         options:kNilOptions
+                                                           error:&jsonError];
+  experiment.experimentPayloads = [@[ payloadData1, payloadData2 ] mutableCopy];
+
+  NSMutableSet<NSString *> *changedKeys = [experiment getKeysAffectedByChangedExperiments];
+  XCTAssertTrue([changedKeys containsObject:@"test_key_1"]);
+}
+
+- (void)testExperimentDiff_changedExperimentMetadata {
+  FIRExperimentController *experimentController =
+      [[FIRExperimentController alloc] initWithAnalytics:nil];
+  id mockExperimentController = OCMPartialMock(experimentController);
+  RCNConfigExperiment *experiment =
+      [[RCNConfigExperiment alloc] initWithDBManager:_DBManagerMock
+                                experimentController:mockExperimentController];
+
+  NSData *payloadData1 = [[self class] payloadDataFromTestFile];
+  experiment.activeExperimentPayloads = [@[ payloadData1 ] mutableCopy];
+
+  NSError *dataError;
+  NSMutableDictionary *payload =
+      [NSJSONSerialization JSONObjectWithData:payloadData1
+                                      options:NSJSONReadingMutableContainers
+                                        error:&dataError];
+  [payload setValue:@"var_2" forKey:@"variantId"];
+  NSError *jsonError;
+  NSData *payloadData2 = [NSJSONSerialization dataWithJSONObject:payload
+                                                         options:kNilOptions
+                                                           error:&jsonError];
+  experiment.experimentPayloads = [@[ payloadData2 ] mutableCopy];
+
+  NSMutableSet<NSString *> *changedKeys = [experiment getKeysAffectedByChangedExperiments];
+  XCTAssertTrue([changedKeys containsObject:@"test_key_1"]);
+}
+
+- (void)testExperimentDiff_changedExperimentKeys {
+  FIRExperimentController *experimentController =
+      [[FIRExperimentController alloc] initWithAnalytics:nil];
+  id mockExperimentController = OCMPartialMock(experimentController);
+  RCNConfigExperiment *experiment =
+      [[RCNConfigExperiment alloc] initWithDBManager:_DBManagerMock
+                                experimentController:mockExperimentController];
+
+  NSData *payloadData1 = [[self class] payloadDataFromTestFile];
+  experiment.activeExperimentPayloads = [@[ payloadData1 ] mutableCopy];
+
+  NSError *dataError;
+  NSMutableDictionary *payload =
+      [NSJSONSerialization JSONObjectWithData:payloadData1
+                                      options:NSJSONReadingMutableContainers
+                                        error:&dataError];
+  [payload setValue:@[ @"test_key_1", @"test_key_2" ] forKey:@"affectedParameterKeys"];
+  NSError *jsonError;
+  NSData *payloadData2 = [NSJSONSerialization dataWithJSONObject:payload
+                                                         options:kNilOptions
+                                                           error:&jsonError];
+  experiment.experimentPayloads = [@[ payloadData2 ] mutableCopy];
+
+  NSMutableSet<NSString *> *changedKeys = [experiment getKeysAffectedByChangedExperiments];
+  XCTAssertTrue([changedKeys containsObject:@"test_key_2"]);
+}
+
+- (void)testExperimentDiff_deletedExperiment {
+  FIRExperimentController *experimentController =
+      [[FIRExperimentController alloc] initWithAnalytics:nil];
+  id mockExperimentController = OCMPartialMock(experimentController);
+  RCNConfigExperiment *experiment =
+      [[RCNConfigExperiment alloc] initWithDBManager:_DBManagerMock
+                                experimentController:mockExperimentController];
+
+  NSData *payloadData1 = [[self class] payloadDataFromTestFile];
+  experiment.activeExperimentPayloads = [@[ payloadData1 ] mutableCopy];
+  experiment.experimentPayloads = [@[] mutableCopy];
+
+  NSMutableSet<NSString *> *changedKeys = [experiment getKeysAffectedByChangedExperiments];
+  XCTAssertTrue([changedKeys containsObject:@"test_key_1"]);
+}
+
+- (void)testExperimentDiff_noChange {
+  FIRExperimentController *experimentController =
+      [[FIRExperimentController alloc] initWithAnalytics:nil];
+  id mockExperimentController = OCMPartialMock(experimentController);
+  RCNConfigExperiment *experiment =
+      [[RCNConfigExperiment alloc] initWithDBManager:_DBManagerMock
+                                experimentController:mockExperimentController];
+
+  NSData *payloadData1 = [[self class] payloadDataFromTestFile];
+  experiment.activeExperimentPayloads = [@[ payloadData1 ] mutableCopy];
+  experiment.experimentPayloads = [@[ payloadData1 ] mutableCopy];
+
+  NSMutableSet<NSString *> *changedKeys = [experiment getKeysAffectedByChangedExperiments];
+  XCTAssertTrue([changedKeys count] == 0);
+}
+
 #pragma mark Helpers.
 
 - (ABTExperimentPayload *)deserializeABTData:(NSData *)payload {

FirebaseRemoteConfig/Tests/Unit/TestABTPayload.txt

@@ -15,5 +15,6 @@
     {
       "experimentId": "exp_1"
     }
-  ]
+  ],
+  "affectedParameterKeys": ["test_key_1"]
 }