FIRApp: don't create new component instances while deleting the app (#4918)

* [FIRComponentContainer removeAllComponents] method introduced.

* FIRApp library registration tests.

* FIRApp: remove all components from container on delete

* Run ./scripts/style.sh

Author: maksymmalyhin

FirebaseCore/Sources/FIRApp.m

@@ -287,6 +287,8 @@ - (void)deleteApp:(FIRAppVoidBoolCallback)completion {
     if (sAllApps && sAllApps[self.name]) {
       FIRLogDebug(kFIRLoggerCore, @"I-COR000006", @"Deleting app named %@", self.name);
 
+      // Remove all registered libraries from the container to avoid creating new instances.
+      [self.container removeAllComponents];
       // Remove all cached instances from the container before deleting the app.
       [self.container removeAllCachedInstances];
 

FirebaseCore/Sources/FIRComponentContainer.m

@@ -203,6 +203,12 @@ - (void)removeAllCachedInstances {
   }
 }
 
+- (void)removeAllComponents {
+  @synchronized(self) {
+    [self.components removeAllObjects];
+  }
+}
+
 @end
 
 NS_ASSUME_NONNULL_END

FirebaseCore/Sources/Private/FIRComponentContainerInternal.h

@@ -37,6 +37,9 @@ NS_ASSUME_NONNULL_BEGIN
 /// Remove all of the cached instances stored and allow them to clean up after themselves.
 - (void)removeAllCachedInstances;
 
+/// Removes all the components. After calling this method no new instances will be created.
+- (void)removeAllComponents;
+
 /// Register a class to provide components for the interoperability system. The class should conform
 /// to `FIRComponentRegistrant` and provide an array of `FIRComponent` objects.
 + (void)registerAsComponentRegistrant:(Class<FIRLibrary>)klass;

FirebaseCore/Tests/Unit/FIRAppTest.m

@@ -88,6 +88,9 @@ - (void)tearDown {
 }
 
 - (void)testConfigure {
+  [self
+      registerLibrariesWithClasses:@ [[FIRTestClassCached class], [FIRTestClassEagerCached class]]];
+
   NSDictionary *expectedUserInfo = [self expectedUserInfoWithAppName:kFIRDefaultAppName
                                                         isDefaultApp:YES];
   [self expectNotificationForObserver:self.observerMock
@@ -102,6 +105,11 @@ - (void)testConfigure {
   XCTAssertEqualObjects(app.name, kFIRDefaultAppName);
   XCTAssertEqualObjects(app.options.clientID, kClientID);
   XCTAssertTrue([FIRApp allApps].count == 1);
+
+  // Check the registered libraries instances available.
+  XCTAssertNotNil(FIR_COMPONENT(FIRTestProtocolCached, app.container));
+  XCTAssertNotNil(FIR_COMPONENT(FIRTestProtocolEagerCached, app.container));
+  XCTAssertNil(FIR_COMPONENT(FIRTestProtocol, app.container));
 }
 
 - (void)testConfigureWithNoDefaultOptions {
@@ -321,13 +329,22 @@ - (void)testAppNamed {
 }
 
 - (void)testDeleteApp {
+  [self
+      registerLibrariesWithClasses:@ [[FIRTestClassCached class], [FIRTestClassEagerCached class]]];
+
   NSString *name = NSStringFromSelector(_cmd);
   FIROptions *options = [[FIROptions alloc] initWithGoogleAppID:kGoogleAppID
                                                     GCMSenderID:kGCMSenderID];
   [FIRApp configureWithName:name options:options];
   FIRApp *app = [FIRApp appNamed:name];
   XCTAssertNotNil(app);
   XCTAssertTrue([FIRApp allApps].count == 1);
+
+  // Check the registered libraries instances available.
+  XCTAssertNotNil(FIR_COMPONENT(FIRTestProtocolCached, app.container));
+  XCTAssertNotNil(FIR_COMPONENT(FIRTestProtocolEagerCached, app.container));
+  XCTAssertNil(FIR_COMPONENT(FIRTestProtocol, app.container));
+
   [self expectNotificationForObserver:self.observerMock
                      notificationName:kFIRAppDeleteNotification
                                object:[FIRApp class]
@@ -342,6 +359,10 @@ - (void)testDeleteApp {
   [self waitForExpectations:@[ expectation ] timeout:1];
   OCMVerifyAll(self.observerMock);
   XCTAssertTrue([FIRApp allApps].count == 0);
+
+  // Check no new library instances created after the app delete.
+  XCTAssertNil(FIR_COMPONENT(FIRTestProtocolCached, app.container));
+  XCTAssertNil(FIR_COMPONENT(FIRTestProtocolEagerCached, app.container));
 }
 
 - (void)testErrorForSubspecConfigurationFailure {
@@ -889,4 +910,10 @@ - (FIROptions *)appOptions {
   return [[FIROptions alloc] initWithGoogleAppID:kGoogleAppID GCMSenderID:kGCMSenderID];
 }
 
+- (void)registerLibrariesWithClasses:(NSArray<Class> *)classes {
+  for (Class klass in classes) {
+    [FIRApp registerInternalLibrary:klass withName:NSStringFromClass(klass) withVersion:@"1.0"];
+  }
+}
+
 @end

FirebaseCore/Tests/Unit/FIRComponentContainerTest.m

@@ -132,6 +132,36 @@ - (void)testRemoveAllCachedInstances {
   XCTAssertNotEqual(eagerInstance1, eagerInstance2);
 }
 
+- (void)testRemoveAllComponents {
+  FIRComponentContainer *container =
+      [self containerWithRegistrants:@ [[FIRTestClass class], [FIRTestClassCached class],
+                                        [FIRTestClassEagerCached class],
+                                        [FIRTestClassCachedWithDep class]]];
+
+  // Retrieve an instance of FIRTestClassCached to ensure it's cached.
+  id<FIRTestProtocolCached> cachedInstance1 = FIR_COMPONENT(FIRTestProtocolCached, container);
+  XCTAssertNotNil(cachedInstance1);
+  id<FIRTestProtocolEagerCached> eagerInstance1 =
+      FIR_COMPONENT(FIRTestProtocolEagerCached, container);
+  XCTAssertNotNil(eagerInstance1);
+
+  // FIRTestClassEagerCached and FIRTestClassCached instances should be cached at this point.
+  XCTAssertTrue(container.cachedInstances.count == 2);
+
+  // Remove all components.
+  [container removeAllComponents];
+
+  // Remove the instances.
+  [container removeAllCachedInstances];
+
+  // Verify that no new instances are created.
+  id<FIRTestProtocolCached> cachedInstance2 = FIR_COMPONENT(FIRTestProtocolCached, container);
+  XCTAssertNil(cachedInstance2);
+  id<FIRTestProtocolEagerCached> eagerInstance2 =
+      FIR_COMPONENT(FIRTestProtocolEagerCached, container);
+  XCTAssertNil(eagerInstance2);
+}
+
 #pragma mark - Instantiation Tests
 
 - (void)testEagerInstantiation {