Validate schema in DevTools extension

drift/lib/src/runtime/api/connection_user.dart

@@ -606,3 +606,15 @@ extension on TransactionExecutor {
     }
   }
 }
+
+/// Exposes the private `_runConnectionZoned` method for other parts of drift.
+///
+/// This is only used by the DevTools extension.
+@internal
+extension RunWithEngine on DatabaseConnectionUser {
+  /// Call the private [_runConnectionZoned] method.
+  Future<T> runConnectionZoned<T>(
+      DatabaseConnectionUser user, Future<T> Function() calculation) {
+    return _runConnectionZoned(user, calculation);
+  }
+}

drift/lib/src/runtime/devtools/service_extension.dart

@@ -2,9 +2,10 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:developer';
 
+import 'package:drift/drift.dart';
 import 'package:drift/src/remote/protocol.dart';
+import 'package:drift/src/runtime/executor/transactions.dart';
 
-import '../query_builder/query_builder.dart';
 import 'devtools.dart';
 
 /// A service extension making asynchronous requests on drift databases
@@ -26,7 +27,7 @@ class DriftServiceExtension {
         final stream = tracked.database.tableUpdates();
         final id = _subscriptionId++;
 
-        stream.listen((event) {
+        _activeSubscriptions[id] = stream.listen((event) {
           postEvent('event', {
             'subscription': id,
             'payload':
@@ -60,6 +61,16 @@ class DriftServiceExtension {
         };
 
         return _protocol.encodePayload(result);
+      case 'collect-expected-schema':
+        final executor = _CollectCreateStatements();
+        await tracked.database.runConnectionZoned(
+            BeforeOpenRunner(tracked.database, executor), () async {
+          // ignore: invalid_use_of_protected_member, invalid_use_of_visible_for_testing_member
+          final migrator = tracked.database.createMigrator();
+          await migrator.createAll();
+        });
+
+        return executor.statements;
       default:
         throw UnsupportedError('Method $action');
     }
@@ -96,3 +107,52 @@ class DriftServiceExtension {
 
   static const _protocol = DriftProtocol();
 }
+
+class _CollectCreateStatements extends QueryExecutor {
+  final List<String> statements = [];
+
+  @override
+  TransactionExecutor beginTransaction() {
+    throw UnimplementedError();
+  }
+
+  @override
+  SqlDialect get dialect => SqlDialect.sqlite;
+
+  @override
+  Future<bool> ensureOpen(QueryExecutorUser user) {
+    return Future.value(true);
+  }
+
+  @override
+  Future<void> runBatched(BatchedStatements statements) {
+    throw UnimplementedError();
+  }
+
+  @override
+  Future<void> runCustom(String statement, [List<Object?>? args]) {
+    statements.add(statement);
+    return Future.value();
+  }
+
+  @override
+  Future<int> runDelete(String statement, List<Object?> args) {
+    throw UnimplementedError();
+  }
+
+  @override
+  Future<int> runInsert(String statement, List<Object?> args) {
+    throw UnimplementedError();
+  }
+
+  @override
+  Future<List<Map<String, Object?>>> runSelect(
+      String statement, List<Object?> args) {
+    throw UnimplementedError();
+  }
+
+  @override
+  Future<int> runUpdate(String statement, List<Object?> args) {
+    throw UnimplementedError();
+  }
+}

drift/lib/src/runtime/devtools/shared.dart

@@ -93,6 +93,7 @@ class EntityDescription {
     return EntityDescription(
       name: entity.entityName,
       type: switch (entity) {
+        VirtualTableInfo() => 'virtual_table',
         TableInfo() => 'table',
         ViewInfo() => 'view',
         Index() => 'index',

drift/pubspec.yaml

@@ -37,3 +37,4 @@ dev_dependencies:
   shelf: ^1.3.0
   stack_trace: ^1.10.0
   test_descriptor: ^2.0.1
+  vm_service: ^13.0.0

drift/test/integration_tests/devtools/app.dart

@@ -0,0 +1,11 @@
+import 'package:drift/native.dart';
+
+import '../../generated/todos.dart';
+
+void main() {
+  TodoDb(NativeDatabase.memory());
+  print('database created');
+
+  // Keep the process alive
+  Stream<void>.periodic(const Duration(seconds: 10)).listen(null);
+}

drift/test/integration_tests/devtools/devtools_test.dart

@@ -0,0 +1,73 @@
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:test/test.dart';
+import 'package:vm_service/vm_service.dart';
+import 'package:path/path.dart' as p;
+import 'package:vm_service/vm_service_io.dart';
+
+void main() {
+  late Process child;
+  late VmService vm;
+  late String isolateId;
+
+  setUpAll(() async {
+    final socket = await ServerSocket.bind(InternetAddress.loopbackIPv4, 0);
+    final port = socket.port;
+    await socket.close();
+
+    String sdk = p.dirname(p.dirname(Platform.resolvedExecutable));
+    child = await Process.start(p.join(sdk, 'bin', 'dart'), [
+      'run',
+      '--enable-vm-service=$port',
+      '--disable-service-auth-codes',
+      '--enable-asserts',
+      'test/integration_tests/devtools/app.dart',
+    ]);
+
+    final vmServiceListening = Completer<void>();
+    final databaseOpened = Completer<void>();
+
+    child.stdout
+        .map(utf8.decode)
+        .transform(const LineSplitter())
+        .listen((line) {
+      if (line.startsWith('The Dart VM service is listening')) {
+        vmServiceListening.complete();
+      } else if (line == 'database created') {
+        databaseOpened.complete();
+      } else if (!line.startsWith('The Dart DevTools')) {
+        print('[child]: $line');
+      }
+    });
+
+    await vmServiceListening.future;
+    vm = await vmServiceConnectUri('ws://localhost:$port/ws');
+
+    final state = await vm.getVM();
+    isolateId = state.isolates!.single.id!;
+
+    await databaseOpened.future;
+  });
+
+  tearDownAll(() async {
+    child.kill();
+  });
+
+  test('can list create statements', () async {
+    final response = await vm.callServiceExtension(
+      'ext.drift.database',
+      args: {'action': 'collect-expected-schema', 'db': '0'},
+      isolateId: isolateId,
+    );
+
+    expect(
+        response.json!['r'],
+        containsAll([
+          'CREATE TABLE IF NOT EXISTS "categories" ("id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, "desc" TEXT NOT NULL UNIQUE, "priority" INTEGER NOT NULL DEFAULT 0, "description_in_upper_case" TEXT NOT NULL GENERATED ALWAYS AS (UPPER("desc")) VIRTUAL);',
+          'CREATE TABLE IF NOT EXISTS "todos" ("id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, "title" TEXT NULL, "content" TEXT NOT NULL, "target_date" INTEGER NULL UNIQUE, "category" INTEGER NULL REFERENCES categories (id), "status" TEXT NULL, UNIQUE ("title", "category"), UNIQUE ("title", "target_date"));',
+          'CREATE TABLE IF NOT EXISTS "shared_todos" ("todo" INTEGER NOT NULL, "user" INTEGER NOT NULL, PRIMARY KEY ("todo", "user"), FOREIGN KEY (todo) REFERENCES todos(id), FOREIGN KEY (user) REFERENCES users(id));'
+        ]));
+  });
+}

drift_dev/lib/api/migrations.dart

@@ -2,10 +2,13 @@ import 'package:drift/drift.dart';
 import 'package:drift/internal/migrations.dart';
 import 'package:drift/native.dart';
 import 'package:drift_dev/src/services/schema/verifier_impl.dart';
+import 'package:drift_dev/src/services/schema/verifier_common.dart';
 import 'package:meta/meta.dart';
 import 'package:sqlite3/sqlite3.dart';
 
 export 'package:drift/internal/migrations.dart';
+export 'package:drift_dev/src/services/schema/verifier_common.dart'
+    show SchemaMismatch;
 
 abstract class SchemaVerifier {
   factory SchemaVerifier(SchemaInstantiationHelper helper) =
@@ -130,18 +133,6 @@ class _GenerateFromScratch extends GeneratedDatabase {
   int get schemaVersion => 1;
 }
 
-/// Thrown when the actual schema differs from the expected schema.
-class SchemaMismatch implements Exception {
-  final String explanation;
-
-  SchemaMismatch(this.explanation);
-
-  @override
-  String toString() {
-    return 'Schema does not match\n$explanation';
-  }
-}
-
 /// Contains an initialized schema with all tables, views, triggers and indices.
 ///
 /// You can use the [newConnection] for your database class and the

drift_dev/lib/src/services/schema/sqlite_to_drift.dart

@@ -1,6 +1,5 @@
 import 'package:analyzer/dart/element/element.dart';
 import 'package:drift_dev/src/analysis/options.dart';
-import 'package:drift_dev/src/services/schema/verifier_impl.dart';
 import 'package:logging/logging.dart';
 import 'package:sqlite3/common.dart';
 import 'package:sqlparser/sqlparser.dart';
@@ -8,6 +7,7 @@ import 'package:sqlparser/sqlparser.dart';
 import '../../analysis/backend.dart';
 import '../../analysis/driver/driver.dart';
 import '../../analysis/results/results.dart';
+import 'verifier_common.dart';
 
 /// Extracts drift elements from the schema of an existing database.
 ///

drift_dev/lib/src/services/schema/verifier_common.dart

@@ -0,0 +1,39 @@
+import 'find_differences.dart';
+
+/// Attempts to recognize whether [name] is likely the name of an internal
+/// sqlite3 table (like `sqlite3_sequence`) that we should not consider when
+/// comparing schemas.
+bool isInternalElement(String name, List<String> virtualTables) {
+  // Skip sqlite-internal tables, https://www.sqlite.org/fileformat2.html#intschema
+  if (name.startsWith('sqlite_')) return true;
+  if (virtualTables.any((v) => name.startsWith('${v}_'))) return true;
+
+  // This file is added on some Android versions when using the native Android
+  // database APIs, https://github.com/simolus3/drift/discussions/2042
+  if (name == 'android_metadata') return true;
+
+  return false;
+}
+
+void verify(List<Input> referenceSchema, List<Input> actualSchema,
+    bool validateDropped) {
+  final result =
+      FindSchemaDifferences(referenceSchema, actualSchema, validateDropped)
+          .compare();
+
+  if (!result.noChanges) {
+    throw SchemaMismatch(result.describe());
+  }
+}
+
+/// Thrown when the actual schema differs from the expected schema.
+class SchemaMismatch implements Exception {
+  final String explanation;
+
+  SchemaMismatch(this.explanation);
+
+  @override
+  String toString() {
+    return 'Schema does not match\n$explanation';
+  }
+}

drift_dev/lib/src/services/schema/verifier_impl.dart

@@ -6,6 +6,7 @@ import 'package:drift_dev/api/migrations.dart';
 import 'package:sqlite3/sqlite3.dart';
 
 import 'find_differences.dart';
+import 'verifier_common.dart';
 
 Expando<List<Input>> expectedSchema = Expando();
 
@@ -94,21 +95,6 @@ Input? _parseInputFromSchemaRow(
   return Input(name, row['sql'] as String);
 }
 
-/// Attempts to recognize whether [name] is likely the name of an internal
-/// sqlite3 table (like `sqlite3_sequence`) that we should not consider when
-/// comparing schemas.
-bool isInternalElement(String name, List<String> virtualTables) {
-  // Skip sqlite-internal tables, https://www.sqlite.org/fileformat2.html#intschema
-  if (name.startsWith('sqlite_')) return true;
-  if (virtualTables.any((v) => name.startsWith('${v}_'))) return true;
-
-  // This file is added on some Android versions when using the native Android
-  // database APIs, https://github.com/simolus3/drift/discussions/2042
-  if (name == 'android_metadata') return true;
-
-  return false;
-}
-
 extension CollectSchemaDb on DatabaseConnectionUser {
   Future<List<Input>> collectSchemaInput(List<String> virtualTables) async {
     final result = await customSelect('SELECT * FROM sqlite_master;').get();
@@ -141,17 +127,6 @@ extension CollectSchema on QueryExecutor {
   }
 }
 
-void verify(List<Input> referenceSchema, List<Input> actualSchema,
-    bool validateDropped) {
-  final result =
-      FindSchemaDifferences(referenceSchema, actualSchema, validateDropped)
-          .compare();
-
-  if (!result.noChanges) {
-    throw SchemaMismatch(result.describe());
-  }
-}
-
 class _DelegatingUser extends QueryExecutorUser {
   @override
   final int schemaVersion;

extras/drift_devtools_extension/lib/src/db_viewer/database.dart

@@ -52,7 +52,10 @@ class ViewerDatabase implements DbViewerDatabase {
   @override
   List<String> get entityNames => [
         for (final entity in database.description.entities)
-          if (entity.type == 'table') entity.name,
+          if (entity.type == 'table' ||
+              entity.type == 'virtual_table' ||
+              entity.type == 'view')
+            entity.name,
       ];
 
   @override

extras/drift_devtools_extension/lib/src/details.dart

@@ -1,4 +1,5 @@
 import 'package:devtools_app_shared/service.dart';
+import 'package:drift_devtools_extension/src/schema_validator.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
@@ -55,6 +56,10 @@ class _DatabaseDetailsState extends ConsumerState<DatabaseDetails> {
             child: ListView(
               controller: controller,
               children: [
+                const Padding(
+                  padding: EdgeInsets.all(8),
+                  child: DatabaseSchemaCheck(),
+                ),
                 Padding(
                   padding: const EdgeInsets.all(8.0),
                   child: Column(

extras/drift_devtools_extension/lib/src/remote_database.dart

@@ -71,6 +71,11 @@ class RemoteDatabase {
     await _executeQuery<void>(ExecuteQuery(StatementMethod.custom, sql, args));
   }
 
+  Future<List<String>> get createStatements async {
+    final res = await _driftRequest('collect-expected-schema');
+    return (res as List).cast();
+  }
+
   Future<int> _newTableSubscription() async {
     final result = await _driftRequest('subscribe-to-tables');
     return result as int;

extras/drift_devtools_extension/lib/src/schema_validator.dart

@@ -0,0 +1,184 @@
+import 'package:devtools_app_shared/ui.dart';
+// ignore: implementation_imports
+import 'package:drift_dev/src/services/schema/find_differences.dart';
+// ignore: implementation_imports
+import 'package:drift_dev/src/services/schema/verifier_common.dart';
+import 'package:flutter/gestures.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:sqlite3/wasm.dart' hide Row;
+import 'package:url_launcher/url_launcher.dart';
+
+import 'details.dart';
+import 'remote_database.dart';
+import 'service.dart';
+
+sealed class SchemaStatus {}
+
+final class DidNotValidateYet implements SchemaStatus {
+  const DidNotValidateYet();
+}
+
+final class SchemaComparisonResult implements SchemaStatus {
+  final bool schemaValid;
+  final String message;
+
+  SchemaComparisonResult({required this.schemaValid, required this.message});
+}
+
+final schemaStateProvider =
+    AsyncNotifierProvider.autoDispose<SchemaVerifier, SchemaStatus>(
+        SchemaVerifier._);
+
+class SchemaVerifier extends AutoDisposeAsyncNotifier<SchemaStatus> {
+  RemoteDatabase? _database;
+  CommonSqlite3? _sqlite3;
+
+  SchemaVerifier._();
+
+  @override
+  Future<SchemaStatus> build() async {
+    _database = await ref.read(loadedDatabase.future);
+    _sqlite3 = await ref.read(sqliteProvider.future);
+
+    return const DidNotValidateYet();
+  }
+
+  Future<void> validate() async {
+    state = const AsyncLoading();
+    state = await AsyncValue.guard<SchemaStatus>(() async {
+      final database = _database!;
+
+      final virtualTables = database.description.entities
+          .where((e) => e.type == 'virtual_table')
+          .map((e) => e.name)
+          .toList();
+
+      final expected = await _inputFromNewDatabase(virtualTables);
+      final actual = <Input>[];
+
+      for (final row in await database
+          .select('SELECT name, sql FROM sqlite_schema;', [])) {
+        final name = row['name'] as String;
+        final sql = row['sql'] as String;
+
+        if (!isInternalElement(name, virtualTables)) {
+          actual.add(Input(name, sql));
+        }
+      }
+
+      try {
+        verify(expected, actual, true);
+        return SchemaComparisonResult(
+          schemaValid: true,
+          message: 'The schema of the database matches its Dart and .drift '
+              'definitions, meaning that migrations are likely correct.',
+        );
+      } on SchemaMismatch catch (e) {
+        return SchemaComparisonResult(
+          schemaValid: false,
+          message: e.toString(),
+        );
+      }
+    });
+  }
+
+  Future<List<Input>> _inputFromNewDatabase(List<String> virtuals) async {
+    final expectedStatements = await _database!.createStatements;
+    final newDatabase = _sqlite3!.openInMemory();
+    final inputs = <Input>[];
+
+    for (var statement in expectedStatements) {
+      newDatabase.execute(statement);
+    }
+
+    for (final row
+        in newDatabase.select('SELECT name, sql FROM sqlite_schema;', [])) {
+      final name = row['name'] as String;
+      final sql = row['sql'] as String;
+
+      if (!isInternalElement(name, virtuals)) {
+        inputs.add(Input(name, sql));
+      }
+    }
+
+    newDatabase.dispose();
+    return inputs;
+  }
+}
+
+class DatabaseSchemaCheck extends ConsumerWidget {
+  const DatabaseSchemaCheck({super.key});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final state = ref.watch(schemaStateProvider);
+
+    final description = switch (state) {
+      AsyncData(
+        value: SchemaComparisonResult(schemaValid: true, :var message)
+      ) =>
+        Text.rich(TextSpan(
+          children: [
+            const TextSpan(
+                text: 'Success! ', style: TextStyle(color: Colors.green)),
+            TextSpan(text: message),
+          ],
+        )),
+      AsyncData(
+        value: SchemaComparisonResult(schemaValid: false, :var message)
+      ) =>
+        Text.rich(TextSpan(
+          children: [
+            const TextSpan(
+                text: 'Mismatch detected! ',
+                style: TextStyle(color: Colors.red)),
+            TextSpan(text: message),
+          ],
+        )),
+      AsyncError(:var error) =>
+        Text('The schema could not be validated due to an error: $error'),
+      _ => Text.rich(TextSpan(
+          text: 'By validating your schema, you can ensure that the current  '
+              'state of the database in your app (after migrations ran) '
+              'matches the expected state of tables as defined in your sources. ',
+          children: [
+            TextSpan(
+              text: 'Learn more',
+              style: const TextStyle(
+                decoration: TextDecoration.underline,
+              ),
+              recognizer: TapGestureRecognizer()
+                ..onTap = () async {
+                  await launchUrl(Uri.parse(
+                      'https://drift.simonbinder.eu/docs/migrations/#verifying-a-database-schema-at-runtime'));
+                },
+            ),
+          ],
+        )),
+    };
+
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.start,
+      children: [
+        Padding(
+          padding: const EdgeInsets.only(bottom: 8),
+          child: description,
+        ),
+        DevToolsButton(
+          label: switch (state) {
+            AsyncError() ||
+            AsyncData(value: SchemaComparisonResult()) =>
+              'Validate again',
+            _ => 'Validate schema',
+          },
+          onPressed: () {
+            if (state is! AsyncLoading) {
+              ref.read(schemaStateProvider.notifier).validate();
+            }
+          },
+        )
+      ],
+    );
+  }
+}

extras/drift_devtools_extension/lib/src/service.dart

@@ -5,6 +5,7 @@ import 'package:devtools_extensions/devtools_extensions.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:rxdart/transformers.dart';
+import 'package:sqlite3/wasm.dart';
 import 'package:vm_service/vm_service.dart';
 
 final _serviceConnection = StreamController<VmService>.broadcast();
@@ -48,3 +49,9 @@ final hotRestartEventProvider =
 
   return notifier;
 });
+
+final sqliteProvider = FutureProvider((ref) async {
+  final sqlite = await WasmSqlite3.loadFromUrl(Uri.parse('sqlite3.wasm'));
+  sqlite.registerVirtualFileSystem(InMemoryFileSystem(), makeDefault: true);
+  return sqlite;
+});

extras/drift_devtools_extension/pubspec.yaml

@@ -15,12 +15,14 @@ dependencies:
   devtools_app_shared: '>=0.0.5 <0.0.6' # 0.0.6 requires unstable Flutter
   db_viewer: ^1.0.3
   rxdart: ^0.27.7
-  flutter_riverpod: ^2.4.4
+  flutter_riverpod: ^3.0.0-dev.0
   vm_service: ^11.10.0
   path: ^1.8.3
   drift: ^2.12.1
   logging: ^1.2.0
   url_launcher: ^6.1.14
+  drift_dev: ^2.13.1
+  sqlite3: ^2.1.0
 
 dev_dependencies:
   flutter_test:

extras/drift_devtools_extension/web/sqlite3.wasm

@@ -0,0 +1 @@
+../../assets/sqlite3.wasm