| // Copyright (c) 2019, the Dart 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. |
| |
| import 'package:analyzer/dart/ast/ast.dart'; |
| import 'package:analyzer/dart/ast/visitor.dart'; |
| import 'package:analyzer/dart/element/element.dart'; |
| import 'package:analyzer/dart/element/type.dart'; |
| |
| import '../analyzer.dart'; |
| import '../extensions.dart'; |
| import '../util/flutter_utils.dart'; |
| |
| const _desc = r'Use key in widget constructors.'; |
| |
| const _details = r''' |
| **DO** use key in widget constructors. |
| |
| It's a good practice to expose the ability to provide a key when creating public |
| widgets. |
| |
| **BAD:** |
| ```dart |
| class MyPublicWidget extends StatelessWidget { |
| } |
| ``` |
| |
| **GOOD:** |
| ```dart |
| class MyPublicWidget extends StatelessWidget { |
| MyPublicWidget({super.key}); |
| } |
| ``` |
| '''; |
| |
| class UseKeyInWidgetConstructors extends LintRule { |
| static const LintCode code = LintCode('use_key_in_widget_constructors', |
| "Constructors for public widgets should have a named 'key' parameter.", |
| correctionMessage: 'Try adding a named parameter to the constructor.'); |
| |
| UseKeyInWidgetConstructors() |
| : super( |
| name: 'use_key_in_widget_constructors', |
| description: _desc, |
| details: _details, |
| group: Group.errors); |
| |
| @override |
| LintCode get lintCode => code; |
| |
| @override |
| void registerNodeProcessors( |
| NodeLintRegistry registry, LinterContext context) { |
| var visitor = _Visitor(this); |
| registry.addClassDeclaration(this, visitor); |
| registry.addConstructorDeclaration(this, visitor); |
| } |
| } |
| |
| class _Visitor extends SimpleAstVisitor<void> { |
| final LintRule rule; |
| |
| _Visitor(this.rule); |
| |
| @override |
| void visitClassDeclaration(ClassDeclaration node) { |
| var classElement = node.declaredElement; |
| if (classElement != null && |
| classElement.isPublic && |
| hasWidgetAsAscendant(classElement) && |
| classElement.constructors.where((e) => !e.isSynthetic).isEmpty) { |
| rule.reportLintForToken(node.name); |
| } |
| super.visitClassDeclaration(node); |
| } |
| |
| @override |
| void visitConstructorDeclaration(ConstructorDeclaration node) { |
| var constructorElement = node.declaredElement; |
| if (constructorElement == null) { |
| return; |
| } |
| var classElement = constructorElement.enclosingElement; |
| if (constructorElement.isPublic && |
| !constructorElement.isFactory && |
| classElement.isPublic && |
| classElement is ClassElement && |
| hasWidgetAsAscendant(classElement) && |
| !isExactWidget(classElement) && |
| !_hasKeySuperParameterInitializerArg(node) && |
| !node.initializers.any((initializer) { |
| if (initializer is SuperConstructorInvocation) { |
| var staticElement = initializer.staticElement; |
| return staticElement != null && |
| (!_defineKeyParameter(staticElement) || |
| _defineKeyArgument(initializer.argumentList)); |
| } else if (initializer is RedirectingConstructorInvocation) { |
| var staticElement = initializer.staticElement; |
| return staticElement != null && |
| (!_defineKeyParameter(staticElement) || |
| _defineKeyArgument(initializer.argumentList)); |
| } |
| return false; |
| })) { |
| var errorNode = node.name ?? node.returnType; |
| rule.reportLintForOffset(errorNode.offset, errorNode.length); |
| } |
| super.visitConstructorDeclaration(node); |
| } |
| |
| bool _defineKeyArgument(ArgumentList argumentList) => argumentList.arguments |
| .any((a) => a.staticParameterElement?.name == 'key'); |
| |
| bool _defineKeyParameter(ConstructorElement element) => |
| element.parameters.any((e) => e.name == 'key' && _isKeyType(e.type)); |
| |
| bool _hasKeySuperParameterInitializerArg(ConstructorDeclaration node) { |
| for (var parameter in node.parameters.parameters) { |
| var element = parameter.declaredElement; |
| if (element is SuperFormalParameterElement && element.name == 'key') { |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| bool _isKeyType(DartType type) => type.implementsInterface('Key', ''); |
| } |