Reset RC per-instance userdefaults if config database was not found.

FirebaseRemoteConfig/Sources/RCNConfigDBManager.h

@@ -115,4 +115,7 @@ typedef void (^RCNDBLoadCompletion)(BOOL success,
 /// Remove all the records from experiment table with given key.
 /// @param key  The key of experiment data belongs to, which are defined in RCNConfigDefines.h.
 - (void)deleteExperimentTableForKey:(NSString *)key;
+
+/// Returns true if this a new install of the Config database.
+- (BOOL)isNewDatabase;
 @end

FirebaseRemoteConfig/Sources/RCNConfigDBManager.m

@@ -31,6 +31,7 @@
 #define RCNTableNameInternalMetadata "internal_metadata"
 #define RCNTableNameExperiment "experiment"
 
+static BOOL gIsNewDatabase;
 /// SQLite file name in versions 0, 1 and 2.
 static NSString *const RCNDatabaseName = @"RemoteConfig.sqlite3";
 /// The application support sub-directory that the Remote Config database resides in.
@@ -77,6 +78,7 @@ static BOOL RemoteConfigCreateFilePathIfNotExist(NSString *filePath) {
   }
   NSFileManager *fileManager = [NSFileManager defaultManager];
   if (![fileManager fileExistsAtPath:filePath]) {
+    gIsNewDatabase = YES;
     NSError *error;
     [fileManager createDirectoryAtPath:[filePath stringByDeletingLastPathComponent]
            withIntermediateDirectories:YES
@@ -203,6 +205,7 @@ - (void)createOrOpenDatabase {
     NSString *dbPath = [RCNConfigDBManager remoteConfigPathForDatabase];
     FIRLogInfo(kFIRLoggerRemoteConfig, @"I-RCN000062", @"Loading database at path %@", dbPath);
     const char *databasePath = dbPath.UTF8String;
+
     // Create or open database path.
     if (!RemoteConfigCreateFilePathIfNotExist(dbPath)) {
       return;
@@ -1036,4 +1039,8 @@ - (BOOL)logErrorWithSQL:(const char *)SQL
   return returnValue;
 }
 
+- (BOOL)isNewDatabase {
+  return gIsNewDatabase;
+}
+
 @end

FirebaseRemoteConfig/Sources/RCNConfigSettings.m

@@ -102,6 +102,14 @@ - (instancetype)initWithDatabaseManager:(RCNConfigDBManager *)manager
     _userDefaultsManager = [[RCNUserDefaultsManager alloc] initWithAppName:appName
                                                                   bundleID:_bundleIdentifier
                                                                  namespace:_FIRNamespace];
+
+    // Check if the config database is new. If so, clear the configs saved in userDefaults.
+    if ([_DBManager isNewDatabase]) {
+      FIRLogNotice(kFIRLoggerRemoteConfig, @"I-RCN000072",
+                   @"New config database created. Resetting user defaults.");
+      [_userDefaultsManager resetUserDefaults];
+    }
+
     _isFetchInProgress = NO;
   }
   return self;

FirebaseRemoteConfig/Sources/RCNUserDefaultsManager.h

@@ -48,6 +48,8 @@ NS_ASSUME_NONNULL_BEGIN
     __attribute__((unavailable("Use `initWithAppName:bundleID:namespace:` instead.")));
 // NOLINTEND
 
+/// Delete all saved userdefaults for this instance.
+- (void)resetUserDefaults;
 @end
 
 NS_ASSUME_NONNULL_END

FirebaseRemoteConfig/Sources/RCNUserDefaultsManager.m

@@ -174,6 +174,11 @@ - (void)setCurrentThrottlingRetryIntervalSeconds:(NSTimeInterval)throttlingRetry
                               forKey:kRCNUserDefaultsKeyNamecurrentThrottlingRetryInterval];
 }
 
+#pragma mark Public methods.
+- (void)resetUserDefaults {
+  [self resetInstanceUserDefaults];
+}
+
 #pragma mark Private methods.
 
 // There is a nested hierarchy for the userdefaults as follows:
@@ -212,4 +217,17 @@ - (void)setInstanceUserDefaultsValue:(NSObject *)value forKey:(NSString *)key {
   }
 }
 
+// Delete any existing userdefaults for this instance.
+- (void)resetInstanceUserDefaults {
+  @synchronized(_userDefaults) {
+    NSMutableDictionary *appUserDefaults = [[self appUserDefaults] mutableCopy];
+    NSMutableDictionary *appNamespaceUserDefaults = [[self instanceUserDefaults] mutableCopy];
+    [appNamespaceUserDefaults removeAllObjects];
+    [appUserDefaults setObject:appNamespaceUserDefaults forKey:_firebaseNamespace];
+    [_userDefaults setObject:appUserDefaults forKey:_firebaseAppName];
+    // We need to synchronize to have this value updated for the extension.
+    [_userDefaults synchronize];
+  }
+}
+
 @end

FirebaseRemoteConfig/Tests/Unit/RCNRemoteConfigTest.m

@@ -192,7 +192,8 @@ - (void)setUp {
                                                                    namespace:fullyQualifiedNamespace
                                                                      options:currentOptions]);
 
-    OCMStub([_configFetch[i] fetchConfigWithExpirationDuration:43200 completionHandler:OCMOCK_ANY])
+    OCMStub([_configFetch[i] fetchConfigWithExpirationDuration:0 completionHandler:OCMOCK_ANY])
+        .ignoringNonObjectArgs()
         .andDo(^(NSInvocation *invocation) {
           void (^handler)(FIRRemoteConfigFetchStatus status, NSError *_Nullable error) = nil;
           [invocation getArgument:&handler atIndex:3];

FirebaseRemoteConfig/Tests/Unit/RCNUserDefaultsManagerTests.m

@@ -170,4 +170,14 @@ - (void)testUserDefaultsForMultipleNamespaces {
                  RCNUserDefaultsSampleTimeStamp - 2.0);
 }
 
+- (void)testUserDefaultsReset {
+  RCNUserDefaultsManager* manager =
+      [[RCNUserDefaultsManager alloc] initWithAppName:@"TESTING"
+                                             bundleID:[NSBundle mainBundle].bundleIdentifier
+                                            namespace:@"testNamespace1"];
+  [manager setLastETag:@"testETag"];
+  [manager resetUserDefaults];
+  XCTAssertNil([manager lastETag]);
+}
+
 @end