Option to generate mutable data classes (#551)

docs/content/en/docs/Advanced Features/builder_options.md

@@ -62,6 +62,8 @@ At the moment, moor supports these options:
    If you're using this flag, please open an issue and explain how the new inference isn't working for you, thanks!
 * `data_class_to_companions` (defaults to `true`): Controls whether moor will write the `toCompanion` method in generated
    data classes.
+* `mutable_classes` (defaults to `false`): The fields generated in generated data, companion and result set classes are final
+  by default. You can make them mutable by setting `mutable_classes: true`.
 
 ## Available extensions
 

moor_generator/lib/src/analyzer/options.dart

@@ -68,6 +68,9 @@ class MoorOptions {
   @JsonKey(name: 'data_class_to_companions', defaultValue: true)
   final bool dataClassToCompanions;
 
+  @JsonKey(name: 'mutable_classes', defaultValue: false)
+  final bool generateMutableClasses;
+
   /// Whether the [module] has been enabled in this configuration.
   bool hasModule(SqlModule module) => modules.contains(module);
 
@@ -82,6 +85,7 @@ class MoorOptions {
     this.legacyTypeInference = false,
     this.eagerlyLoadDartAst = false,
     this.dataClassToCompanions = true,
+    this.generateMutableClasses = false,
     this.modules = const [],
   });
 

moor_generator/lib/src/analyzer/options.g.dart

@@ -19,7 +19,8 @@ MoorOptions _$MoorOptionsFromJson(Map<String, dynamic> json) {
       'legacy_type_inference',
       'sqlite_modules',
       'eagerly_load_dart_ast',
-      'data_class_to_companions'
+      'data_class_to_companions',
+      'mutable_classes'
     ]);
     final val = MoorOptions(
       generateFromJsonStringConstructor: $checkedConvert(
@@ -54,6 +55,8 @@ MoorOptions _$MoorOptionsFromJson(Map<String, dynamic> json) {
       dataClassToCompanions:
           $checkedConvert(json, 'data_class_to_companions', (v) => v as bool) ??
               true,
+      generateMutableClasses:
+          $checkedConvert(json, 'mutable_classes', (v) => v as bool) ?? false,
       modules: $checkedConvert(
               json,
               'sqlite_modules',
@@ -76,6 +79,7 @@ MoorOptions _$MoorOptionsFromJson(Map<String, dynamic> json) {
     'legacyTypeInference': 'legacy_type_inference',
     'eagerlyLoadDartAst': 'eagerly_load_dart_ast',
     'dataClassToCompanions': 'data_class_to_companions',
+    'generateMutableClasses': 'mutable_classes',
     'modules': 'sqlite_modules'
   });
 }

moor_generator/lib/src/writer/queries/result_set_writer.dart

@@ -14,11 +14,14 @@ class ResultSetWriter {
     final into = scope.leaf();
 
     into.write('class $className {\n');
+    final modifier = scope.options.fieldModifier;
+
     // write fields
     for (final column in query.resultSet.columns) {
       final name = query.resultSet.dartNameFor(column);
       final runtimeType = column.dartType;
-      into.write('final $runtimeType $name\n;');
+
+      into.write('$modifier $runtimeType $name\n;');
 
       fieldNames.add(name);
     }
@@ -27,7 +30,7 @@ class ResultSetWriter {
       final typeName = nested.table.dartTypeName;
       final fieldName = nested.dartFieldName;
 
-      into.write('final $typeName $fieldName;\n');
+      into.write('$modifier $typeName $fieldName;\n');
 
       fieldNames.add(fieldName);
     }

moor_generator/lib/src/writer/tables/data_class_writer.dart

@@ -19,8 +19,9 @@ class DataClassWriter {
 
     // write individual fields
     for (final column in table.columns) {
-      _buffer
-          .write('final ${column.dartTypeName} ${column.dartGetterName}; \n');
+      final modifier = scope.options.fieldModifier;
+      _buffer.write(
+          '$modifier ${column.dartTypeName} ${column.dartGetterName}; \n');
     }
 
     // write constructor with named optional fields

moor_generator/lib/src/writer/tables/update_companion_writer.dart

@@ -30,7 +30,8 @@ class UpdateCompanionWriter {
 
   void _writeFields() {
     for (final column in table.columns) {
-      _buffer.write('final Value<${column.dartTypeName}>'
+      final modifier = scope.options.fieldModifier;
+      _buffer.write('$modifier Value<${column.dartTypeName}>'
           ' ${column.dartGetterName};\n');
     }
   }

moor_generator/lib/src/writer/writer.dart

@@ -121,3 +121,7 @@ class DartScope {
     return other._id >= _id;
   }
 }
+
+extension WriterUtilsForOptions on MoorOptions {
+  String get fieldModifier => generateMutableClasses ? '' : 'final';
+}

moor_generator/test/writer/mutable_classes_integration_test.dart

@@ -0,0 +1,108 @@
+import 'package:analyzer/dart/analysis/features.dart';
+import 'package:analyzer/dart/analysis/utilities.dart';
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/file_system/memory_file_system.dart';
+import 'package:build/build.dart';
+import 'package:build_test/build_test.dart';
+import 'package:moor_generator/src/backends/build/moor_builder.dart';
+import 'package:test/test.dart';
+
+const _testInput = r'''
+import 'package:moor/moor.dart';
+
+part 'main.moor.dart';
+
+class Users extends Table {
+  IntColumn get id => integer().autoIncrement()();
+  TextColumn get name => text()();
+}
+
+@UseMoor(
+  tables: [Users],
+  queries: {
+    'someQuery': 'SELECT 1 AS foo, 2 AS bar;',
+  },
+)
+class Database extends _$Database {}
+''';
+
+void main() {
+  test('generates mutable classes if needed', () async {
+    await testBuilder(
+      MoorPartBuilder(const BuilderOptions({'mutable_classes': true})),
+      const {'a|lib/main.dart': _testInput},
+      reader: await PackageAssetReader.currentIsolate(),
+      outputs: const {
+        'a|lib/main.moor.dart': _GeneratesWithoutFinalFields(
+          {'User', 'UsersCompanion', 'SomeQueryResult'},
+        ),
+      },
+    );
+  }, tags: 'analyzer');
+}
+
+class _GeneratesWithoutFinalFields extends Matcher {
+  final Set<String> expectedWithoutFinals;
+
+  const _GeneratesWithoutFinalFields(this.expectedWithoutFinals);
+
+  @override
+  Description describe(Description description) {
+    return description.add('generates classes $expectedWithoutFinals without '
+        'final fields.');
+  }
+
+  @override
+  bool matches(dynamic desc, Map matchState) {
+    // Parse the file, assure we don't have final fields in data classes.
+    final resourceProvider = MemoryResourceProvider();
+    if (desc is List<int>) {
+      resourceProvider.newFileWithBytes('/foo.dart', desc);
+    } else if (desc is String) {
+      resourceProvider.newFile('/foo.dart', desc);
+    } else {
+      desc['desc'] = 'Neither a List<int> or String - cannot be parsed';
+      return false;
+    }
+
+    final parsed = parseFile(
+      path: '/foo.dart',
+      featureSet: FeatureSet.forTesting(),
+      resourceProvider: resourceProvider,
+    ).unit;
+
+    final remaining = expectedWithoutFinals.toSet();
+
+    final definedClasses = parsed.declarations.whereType<ClassDeclaration>();
+    for (final definedClass in definedClasses) {
+      if (expectedWithoutFinals.contains(definedClass.name.name)) {
+        final fields = definedClass.members.whereType<FieldDeclaration>();
+
+        for (final field in fields) {
+          if (field.fields.isFinal) {
+            matchState['desc'] =
+                'Field ${field.fields.variables.first.name.name} in '
+                '${definedClass.name.name} is final.';
+            return false;
+          }
+        }
+
+        remaining.remove(definedClass.name.name);
+      }
+    }
+
+    // Also ensure that all expected classes were generated.
+    if (remaining.isNotEmpty) {
+      matchState['desc'] = 'Did not generate $remaining classes';
+      return false;
+    }
+
+    return true;
+  }
+
+  @override
+  Description describeMismatch(dynamic item, Description mismatchDescription,
+      Map matchState, bool verbose) {
+    return mismatchDescription.add(matchState['desc'] as String);
+  }
+}