Generate null variables

drift/lib/src/runtime/query_builder/expressions/variables.dart

@@ -84,11 +84,9 @@ class Variable<T extends Object> extends Expression<T> {
         ..write(mark)
         ..write(explicitStart + context.amountOfVariables);
       context.introduceVariable(this, mapToSimpleValue(context));
-    } else if (value != null) {
+    } else {
       context.buffer.write(mark);
       context.introduceVariable(this, mapToSimpleValue(context));
-    } else {
-      context.buffer.write('NULL');
     }
   }
 

drift/test/database/expressions/variable_test.dart

@@ -16,6 +16,10 @@ void main() {
     expect(ctx.boundVariables, [1551297563]);
   });
 
+  test('maps null to null', () {
+    expect(Variable<Object>(null), generates('?', [null]));
+  });
+
   group('can write variables with wrong type parameter', () {
     test('true', () {
       expect(const Variable<Object>(true), generates('?', [1]));
@@ -52,16 +56,6 @@ void main() {
     });
   });
 
-  test('writes null directly for null values', () {
-    const variable = Variable<String>(null);
-    final ctx = GenerationContext.fromDb(TodoDb());
-
-    variable.writeInto(ctx);
-
-    expect(ctx.sql, 'NULL');
-    expect(ctx.boundVariables, isEmpty);
-  });
-
   test('writes constants when variables are not supported', () {
     const variable = Variable("hello world'");
     final ctx = GenerationContext.fromDb(TodoDb(), supportsVariables: false);

drift/test/database/statements/insert_test.dart

@@ -1,4 +1,4 @@
-import 'package:drift/drift.dart';
+import 'package:drift/drift.dart' hide isNull;
 import 'package:mockito/mockito.dart';
 import 'package:test/test.dart';
 
@@ -37,8 +37,8 @@ void main() {
     verify(executor.runInsert(
         'INSERT INTO table_without_p_k '
         '(not_really_an_id, some_float, web_safe_int, custom) '
-        'VALUES (?, ?, NULL, ?)',
-        [42, 3.1415, anything]));
+        'VALUES (?, ?, ?, ?)',
+        [42, 3.1415, isNull, anything]));
   });
 
   test('can insert BigInt values', () async {
@@ -156,7 +156,8 @@ void main() {
           TodosTableCompanion.insert(content: 'content', title: Value(null)));
 
       verify(executor.runInsert(
-          'INSERT INTO todos (title, content) VALUES (NULL, ?)', ['content']));
+          'INSERT INTO todos (title, content) VALUES (?, ?)',
+          [null, 'content']));
     });
   });
 

drift/test/database/statements/update_test.dart

@@ -61,8 +61,8 @@ void main() {
 
       verify(executor.runUpdate(
           'UPDATE todos SET title = ?, content = ?, '
-          'target_date = NULL, category = NULL WHERE id = ?;',
-          ['Title', 'Updated content', 3]));
+          'target_date = ?, category = ? WHERE id = ?;',
+          ['Title', 'Updated content', null, null, 3]));
     });
 
     test('applies default values', () async {

drift_sqflite/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.0.1
+
+- Fix batch implementation to not start a second transaction.
+
 ## 2.0.0
 
 - Support `drift` version `2.0.0`.

drift_sqflite/lib/drift_sqflite.dart

@@ -74,7 +74,7 @@ class _SqfliteDelegate extends DatabaseDelegate {
       batch.execute(statements.statements[arg.statementIndex], arg.arguments);
     }
 
-    await batch.commit(noResult: true);
+    await batch.apply(noResult: true);
   }
 
   @override

drift_sqflite/pubspec.yaml

@@ -1,6 +1,6 @@
 name: drift_sqflite
 description: A Flutter-only implementation of a drift database, based on the `sqflite` package.
-version: 2.0.0
+version: 2.0.1
 repository: https://github.com/simolus3/drift
 homepage: https://drift.simonbinder.eu/
 issue_tracker: https://github.com/simolus3/drift/issues
@@ -10,7 +10,7 @@ environment:
 
 dependencies:
   drift: ^2.0.0
-  sqflite: ^2.0.0+3
+  sqflite: ^2.1.0
   path: ^1.8.0
   flutter:
     sdk: flutter

extras/integration_tests/drift_testcases/lib/suite/crud_tests.dart

@@ -111,4 +111,47 @@ void crudTests(TestExecutor executor) {
     expect(await db.friendsOf(1).get(), isNotEmpty);
     await executor.clearDatabaseAndClose(db);
   });
+
+  group('bind variable', () {
+    late Database database;
+
+    setUp(() => database = Database(executor.createConnection()));
+    tearDown(() => executor.clearDatabaseAndClose(database));
+
+    Future<T?> evaluate<T extends Object>(Expression<T> expr) async {
+      final query = database.selectOnly(database.users)
+        ..addColumns([expr])
+        ..limit(1);
+      final row = await query.getSingle();
+      return row.read(expr);
+    }
+
+    test('null', () {
+      expect(evaluate(Variable<String>(null)), completion(isNull));
+    });
+
+    test('string', () {
+      expect(evaluate(Variable<String>('foo bar')), completion('foo bar'));
+      expect(evaluate(Variable<String>('')), completion(''));
+    });
+
+    test('boolean', () {
+      expect(evaluate(Variable<bool>(true)), completion(isTrue));
+      expect(evaluate(Variable<bool>(false)), completion(isFalse));
+    });
+
+    test('int', () {
+      expect(evaluate(Variable<double>(42)), completion(42));
+    });
+
+    test('double', () {
+      expect(evaluate(Variable<double>(3.14)), completion(3.14));
+    });
+
+    test('Uint8List', () {
+      final list = Uint8List.fromList(List.generate(12, (index) => index));
+
+      expect(evaluate(Variable<Uint8List>(list)), completion(list));
+    });
+  });
 }

extras/integration_tests/drift_testcases/lib/tests.dart

@@ -1,6 +1,6 @@
 library tests;
 
-export 'package:drift/drift.dart';
+export 'package:drift/drift.dart' hide isNull, isNotNull;
 
 export 'data/sample_data.dart';
 export 'database/database.dart';