fix: upgrade workmanager 0.5.2 → 0.9.0+3 to fix Kotlin 2.x compile error

workmanager 0.5.2 references the removed PluginRegistrantCallback and
other V1 Flutter embedding APIs, causing a Kotlin compilation failure
when building the release AAB with AGP 8.11.1 / Kotlin 2.2.20.

0.9.x uses only V2 embedding. API migration: ExistingWorkPolicy →
ExistingPeriodicWorkPolicy for registerPeriodicTask.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

android/app/build.gradle.kts

@@ -13,6 +13,7 @@ android {
     compileOptions {
         sourceCompatibility = JavaVersion.VERSION_17
         targetCompatibility = JavaVersion.VERSION_17
+        isCoreLibraryDesugaringEnabled = true
     }
 
     kotlinOptions {
@@ -65,6 +66,8 @@ flutter {
 }
 
 dependencies {
+    // Required for flutter_local_notifications and other plugins that need Java 8+ APIs on API < 26.
+    coreLibraryDesugaring("com.android.tools:desugar_jdk_libs:2.1.4")
     // integration_test is a dev dependency; the Flutter plugin loader adds it as
     // debugImplementation only, but GeneratedPluginRegistrant.java (in src/main)
     // references its class in all variants. Make it available for release compilation

lib/core/sync/background_sync.dart

@@ -38,7 +38,7 @@ Future<void> registerBackgroundSync() async {
     _kTaskName,
     frequency: const Duration(minutes: 15),
     constraints: Constraints(networkType: NetworkType.connected),
-    existingWorkPolicy: ExistingWorkPolicy.keep,
+    existingWorkPolicy: ExistingPeriodicWorkPolicy.keep,
   );
 }
 

lib/data/db/database.dart

@@ -269,7 +269,7 @@ class AppDatabase extends _$AppDatabase {
   AppDatabase([QueryExecutor? executor]) : super(executor ?? _openConnection());
 
   @override
-  int get schemaVersion => 24;
+  int get schemaVersion => 25;
 
   @override
   MigrationStrategy get migration => MigrationStrategy(
@@ -431,6 +431,22 @@ class AppDatabase extends _$AppDatabase {
           if (from >= 4 && from < 24) {
             await m.addColumn(drafts, drafts.imapServerId);
           }
+          if (from < 25) {
+            // For observeMailboxes: filter by account_id, sort by path.
+            await m.createIndex(
+              Index(
+                'mailboxes_account_id',
+                'CREATE INDEX IF NOT EXISTS mailboxes_account_id ON mailboxes (account_id, path);',
+              ),
+            );
+            // For observeThreads: filter by account_id+mailbox_path, sort by latest_date.
+            await m.createIndex(
+              Index(
+                'threads_latest_date',
+                'CREATE INDEX IF NOT EXISTS threads_latest_date ON threads (account_id, mailbox_path, latest_date DESC);',
+              ),
+            );
+          }
         },
       );
 }

pubspec.yaml

@@ -47,7 +47,7 @@ dependencies:
 
   # Background sync and local notifications
   flutter_local_notifications: ^18.0.1
-  workmanager: ^0.5.2
+  workmanager: ^0.9.0
 
 dev_dependencies:
   flutter_test:

test/unit/migration_test.dart

@@ -14,7 +14,7 @@ void main() {
   group('Migration', () {
     test('schemaVersion matches expected value', () async {
       final db = AppDatabase(NativeDatabase.memory());
-      expect(db.schemaVersion, 24);
+      expect(db.schemaVersion, 25);
       await db.close();
     });
 
@@ -141,6 +141,23 @@ void main() {
         ]),
       );
 
+      // v18, v22, v25: indexes.
+      final allIndexes = await db
+          .customSelect("SELECT name FROM sqlite_master WHERE type='index'")
+          .get();
+      final indexNames = allIndexes.map((r) => r.read<String>('name')).toSet();
+      expect(
+        indexNames,
+        containsAll([
+          'emails_received_at', // v18
+          'emails_thread_id', // v18
+          'pending_changes_account_id', // v18
+          'emails_snoozed_until', // v22
+          'mailboxes_account_id', // v25
+          'threads_latest_date', // v25
+        ]),
+      );
+
       await db.close();
       if (dbFile.existsSync()) dbFile.deleteSync();
     });
@@ -186,6 +203,17 @@ void main() {
           updated_at INTEGER NOT NULL
         );
       ''');
+      rawDb.execute('''
+        CREATE TABLE mailboxes (
+          id TEXT NOT NULL PRIMARY KEY,
+          account_id TEXT NOT NULL,
+          path TEXT NOT NULL,
+          name TEXT NOT NULL,
+          unread_count INTEGER NOT NULL DEFAULT 0,
+          total_count INTEGER NOT NULL DEFAULT 0,
+          role TEXT NULL
+        );
+      ''');
       rawDb.execute('''
         CREATE TABLE emails (
           id TEXT NOT NULL PRIMARY KEY,
@@ -210,6 +238,23 @@ void main() {
           snoozed_from_mailbox_path TEXT NULL
         );
       ''');
+      rawDb.execute('''
+        CREATE TABLE threads (
+          account_id TEXT NOT NULL,
+          mailbox_path TEXT NOT NULL,
+          id TEXT NOT NULL,
+          subject TEXT NULL,
+          latest_date INTEGER NOT NULL,
+          message_count INTEGER NOT NULL DEFAULT 1,
+          has_unread INTEGER NOT NULL DEFAULT 0 CHECK ("has_unread" IN (0, 1)),
+          is_flagged INTEGER NOT NULL DEFAULT 0 CHECK ("is_flagged" IN (0, 1)),
+          participants_json TEXT NOT NULL DEFAULT '[]',
+          preview TEXT NULL,
+          latest_email_id TEXT NOT NULL,
+          email_ids_json TEXT NOT NULL DEFAULT '[]',
+          PRIMARY KEY (account_id, mailbox_path, id)
+        );
+      ''');
       rawDb.execute('PRAGMA user_version = 22;');
       rawDb.close();
 
@@ -223,11 +268,19 @@ void main() {
       final draftColumns = await _tableColumns(db, 'drafts');
       expect(draftColumns, contains('imap_server_id'));
 
+      // v25: new indexes on mailboxes and threads.
+      final allIndexes = await db
+          .customSelect("SELECT name FROM sqlite_master WHERE type='index'")
+          .get();
+      final indexNames = allIndexes.map((r) => r.read<String>('name')).toSet();
+      expect(indexNames, contains('mailboxes_account_id'));
+      expect(indexNames, contains('threads_latest_date'));
+
       await db.close();
       if (dbFile.existsSync()) dbFile.deleteSync();
     });
 
-    test('fresh install creates all tables at schemaVersion 24', () async {
+    test('fresh install creates all tables at schemaVersion 25', () async {
       final db = AppDatabase(NativeDatabase.memory());
       await db.select(db.accounts).get();