fix(auth, windows): add pluginregistry to properly restore state on Windows

packages/firebase_auth/firebase_auth/example/pubspec.yaml

@@ -11,7 +11,7 @@ dependencies:
   firebase_messaging: ^16.1.1
   flutter:
     sdk: flutter
-  flutter_facebook_auth: ^7.0.1
+  flutter_facebook_auth: ^7.1.5
   flutter_signin_button: ^2.0.0
   google_sign_in: ^6.1.0
   google_sign_in_dartio: ^0.3.0

packages/firebase_auth/firebase_auth/windows/firebase_auth_plugin.cpp

@@ -53,6 +53,9 @@ void FirebaseAuthPlugin::RegisterWithRegistrar(
   FirebaseAuthHostApi::SetUp(registrar->messenger(), plugin.get());
   FirebaseAuthUserHostApi::SetUp(registrar->messenger(), plugin.get());
 
+  RegisterFlutterFirebasePlugin("plugins.flutter.io/firebase_auth",
+                                plugin.get());
+
   registrar->AddPlugin(std::move(plugin));
 
   binaryMessenger = registrar->messenger();
@@ -1283,4 +1286,35 @@ void FirebaseAuthPlugin::RevokeTokenWithAuthorizationCode(
       nullptr));
 }
 
+flutter::EncodableMap FirebaseAuthPlugin::GetPluginConstantsForFirebaseApp(
+    const firebase::App& app) {
+  flutter::EncodableMap constants;
+
+  Auth* auth = Auth::GetAuth(const_cast<firebase::App*>(&app));
+  firebase::auth::User user = auth->current_user();
+
+  if (user.is_valid()) {
+    PigeonUserDetails userDetails = ParseUserDetails(user);
+    flutter::EncodableList userDetailsList;
+    userDetailsList.push_back(
+        flutter::EncodableValue(userDetails.user_info().ToEncodableList()));
+    userDetailsList.push_back(
+        flutter::EncodableValue(userDetails.provider_data()));
+    constants[flutter::EncodableValue("APP_CURRENT_USER")] =
+        flutter::EncodableValue(userDetailsList);
+  }
+
+  std::string lang = auth->language_code();
+  if (!lang.empty()) {
+    constants[flutter::EncodableValue("APP_LANGUAGE_CODE")] =
+        flutter::EncodableValue(lang);
+  }
+
+  return constants;
+}
+
+void FirebaseAuthPlugin::DidReinitializeFirebaseCore() {
+  // No-op for now. Could be used to reset cached auth instances.
+}
+
 }  // namespace firebase_auth_windows

packages/firebase_auth/firebase_auth/windows/firebase_auth_plugin.h

@@ -16,6 +16,7 @@
 #include "firebase/auth.h"
 #include "firebase/auth/types.h"
 #include "firebase/future.h"
+#include "firebase_core/flutter_firebase_plugin.h"
 #include "messages.g.h"
 
 using firebase::auth::AuthError;
@@ -24,7 +25,8 @@ namespace firebase_auth_windows {
 
 class FirebaseAuthPlugin : public flutter::Plugin,
                            public FirebaseAuthHostApi,
-                           public FirebaseAuthUserHostApi {
+                           public FirebaseAuthUserHostApi,
+                           public FlutterFirebasePlugin {
  public:
   static void RegisterWithRegistrar(flutter::PluginRegistrarWindows* registrar);
 
@@ -180,6 +182,11 @@ class FirebaseAuthPlugin : public flutter::Plugin,
       const AuthPigeonFirebaseApp& app, const std::string& authorization_code,
       std::function<void(std::optional<FlutterError> reply)> result) override;
 
+  // FlutterFirebasePlugin methods.
+  flutter::EncodableMap GetPluginConstantsForFirebaseApp(
+      const firebase::App& app) override;
+  void DidReinitializeFirebaseCore() override;
+
  private:
   static flutter::BinaryMessenger* binaryMessenger;
 };

packages/firebase_core/firebase_core/windows/CMakeLists.txt

@@ -65,6 +65,8 @@ list(APPEND PLUGIN_SOURCES
   "firebase_core_plugin.h"
   "messages.g.cpp"
   "messages.g.h"
+  "flutter_firebase_plugin_registry.h"
+  "flutter_firebase_plugin_registry.cpp"
 )
 
 # Read version from pubspec.yaml

packages/firebase_core/firebase_core/windows/firebase_core_plugin.cpp

@@ -9,6 +9,7 @@
 
 #include "firebase/app.h"
 #include "firebase_core/plugin_version.h"
+#include "flutter_firebase_plugin_registry.h"
 #include "messages.g.h"
 
 // For getPlatformVersion; remove unless needed for your plugin implementation.
@@ -95,7 +96,8 @@ CoreFirebaseOptions optionsFromFIROptions(const firebase::AppOptions& options) {
 
 // Convert a firebase::App to CoreInitializeResponse
 CoreInitializeResponse AppToCoreInitializeResponse(const App& app) {
-  flutter::EncodableMap plugin_constants;
+  flutter::EncodableMap plugin_constants =
+      FlutterFirebasePluginRegistry::GetPluginConstantsForFirebaseApp(app);
   CoreInitializeResponse response = CoreInitializeResponse(
       app.name(), optionsFromFIROptions(app.options()), plugin_constants);
   return response;
@@ -116,7 +118,11 @@ void FirebaseCorePlugin::InitializeApp(
 
 void FirebaseCorePlugin::InitializeCore(
     std::function<void(ErrorOr<flutter::EncodableList> reply)> result) {
-  // TODO: Missing function to get the list of currently initialized apps
+  if (coreInitialized) {
+    FlutterFirebasePluginRegistry::DidReinitializeFirebaseCore();
+  }
+  coreInitialized = true;
+
   std::vector<CoreInitializeResponse> initializedApps;
   std::vector<App*> all_apps = App::GetApps();
   for (const App* app : all_apps) {

packages/firebase_core/firebase_core/windows/firebase_core_plugin_c_api.cpp

@@ -10,10 +10,17 @@
 #include <vector>
 
 #include "firebase_core_plugin.h"
+#include "flutter_firebase_plugin_registry.h"
 
 void FirebaseCorePluginCApiRegisterWithRegistrar(
     FlutterDesktopPluginRegistrarRef registrar) {
   firebase_core_windows::FirebaseCorePlugin::RegisterWithRegistrar(
       flutter::PluginRegistrarManager::GetInstance()
           ->GetRegistrar<flutter::PluginRegistrarWindows>(registrar));
 }
+
+void RegisterFlutterFirebasePlugin(const std::string& channel_name,
+                                   FlutterFirebasePlugin* plugin) {
+  firebase_core_windows::FlutterFirebasePluginRegistry::RegisterPlugin(
+      channel_name, plugin);
+}

packages/firebase_core/firebase_core/windows/flutter_firebase_plugin_registry.cpp

@@ -0,0 +1,39 @@
+// Copyright 2023, the Chromium project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#include "flutter_firebase_plugin_registry.h"
+
+namespace firebase_core_windows {
+
+std::unordered_map<std::string, FlutterFirebasePlugin*>&
+FlutterFirebasePluginRegistry::GetRegisteredPlugins() {
+  static std::unordered_map<std::string, FlutterFirebasePlugin*> plugins;
+  return plugins;
+}
+
+void FlutterFirebasePluginRegistry::RegisterPlugin(
+    const std::string& channel_name, FlutterFirebasePlugin* plugin) {
+  GetRegisteredPlugins()[channel_name] = plugin;
+}
+
+flutter::EncodableMap
+FlutterFirebasePluginRegistry::GetPluginConstantsForFirebaseApp(
+    const firebase::App& app) {
+  flutter::EncodableMap all_constants;
+  for (const auto& entry : GetRegisteredPlugins()) {
+    flutter::EncodableMap plugin_constants =
+        entry.second->GetPluginConstantsForFirebaseApp(app);
+    all_constants[flutter::EncodableValue(entry.first)] =
+        flutter::EncodableValue(plugin_constants);
+  }
+  return all_constants;
+}
+
+void FlutterFirebasePluginRegistry::DidReinitializeFirebaseCore() {
+  for (const auto& entry : GetRegisteredPlugins()) {
+    entry.second->DidReinitializeFirebaseCore();
+  }
+}
+
+}  // namespace firebase_core_windows

packages/firebase_core/firebase_core/windows/flutter_firebase_plugin_registry.h

@@ -0,0 +1,43 @@
+// Copyright 2023, the Chromium project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#ifndef FLUTTER_FIREBASE_PLUGIN_REGISTRY_H_
+#define FLUTTER_FIREBASE_PLUGIN_REGISTRY_H_
+
+#include <flutter/encodable_value.h>
+
+#include <string>
+#include <unordered_map>
+
+#include "firebase/app.h"
+#include "include/firebase_core/flutter_firebase_plugin.h"
+
+namespace firebase_core_windows {
+
+// Static registry that collects plugin constants from all registered Firebase
+// plugins during initializeCore, mirroring Android's
+// FlutterFirebasePluginRegistry.
+class FlutterFirebasePluginRegistry {
+ public:
+  // Registers a plugin with the given channel name.
+  static void RegisterPlugin(const std::string& channel_name,
+                             FlutterFirebasePlugin* plugin);
+
+  // Collects constants from all registered plugins for the given app.
+  // Returns a map keyed by channel name, with each value being the plugin's
+  // constants map.
+  static flutter::EncodableMap GetPluginConstantsForFirebaseApp(
+      const firebase::App& app);
+
+  // Notifies all registered plugins that Firebase core was re-initialized.
+  static void DidReinitializeFirebaseCore();
+
+ private:
+  static std::unordered_map<std::string, FlutterFirebasePlugin*>&
+  GetRegisteredPlugins();
+};
+
+}  // namespace firebase_core_windows
+
+#endif  // FLUTTER_FIREBASE_PLUGIN_REGISTRY_H_

packages/firebase_core/firebase_core/windows/include/firebase_core/firebase_core_plugin_c_api.h

@@ -12,6 +12,8 @@
 #include <string>
 #include <vector>
 
+#include "flutter_firebase_plugin.h"
+
 #ifdef FLUTTER_PLUGIN_IMPL
 #define FLUTTER_PLUGIN_EXPORT __declspec(dllexport)
 #else
@@ -21,4 +23,10 @@
 FLUTTER_PLUGIN_EXPORT void FirebaseCorePluginCApiRegisterWithRegistrar(
     FlutterDesktopPluginRegistrarRef registrar);
 
+// Registers a FlutterFirebasePlugin so that its constants are collected during
+// Firebase.initializeApp(). The channel_name should match the Dart
+// MethodChannel name (e.g. "plugins.flutter.io/firebase_auth").
+FLUTTER_PLUGIN_EXPORT void RegisterFlutterFirebasePlugin(
+    const std::string& channel_name, FlutterFirebasePlugin* plugin);
+
 #endif  // FLUTTER_PLUGIN_FIREBASE_CORE_PLUGIN_C_API_H_

packages/firebase_core/firebase_core/windows/include/firebase_core/flutter_firebase_plugin.h

@@ -0,0 +1,29 @@
+// Copyright 2023, the Chromium project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#ifndef FLUTTER_FIREBASE_PLUGIN_H_
+#define FLUTTER_FIREBASE_PLUGIN_H_
+
+#include <flutter/encodable_value.h>
+
+#include "firebase/app.h"
+
+// Abstract interface mirroring Android's FlutterFirebasePlugin.java and iOS's
+// FLTFirebasePlugin.h. Each Firebase plugin implements this to provide initial
+// constants (e.g. current user) during Firebase.initializeApp().
+class FlutterFirebasePlugin {
+ public:
+  virtual ~FlutterFirebasePlugin() {}
+
+  // Returns a map of plugin-specific constants for the given Firebase app.
+  // Called synchronously during initializeCore to populate pluginConstants.
+  virtual flutter::EncodableMap GetPluginConstantsForFirebaseApp(
+      const firebase::App& app) = 0;
+
+  // Called when Firebase core is re-initialized, allowing plugins to reset
+  // their state.
+  virtual void DidReinitializeFirebaseCore() = 0;
+};
+
+#endif  // FLUTTER_FIREBASE_PLUGIN_H_