| // Copyright (c) 2016, 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 '../analyzer.dart'; |
| import '../util/dart_type_utilities.dart'; |
| |
| const _desc = r'Property getter recursively returns itself.'; |
| |
| const _details = r''' |
| |
| **DON'T** create recursive getters. |
| |
| Recursive getters are getters which return themselves as a value. This is |
| usually a typo. |
| |
| **BAD:** |
| ``` |
| int get field => field; // LINT |
| ``` |
| |
| **BAD:** |
| ``` |
| int get otherField { |
| return otherField; // LINT |
| } |
| ``` |
| |
| **GOOD:** |
| ``` |
| int get field => _field; |
| ``` |
| |
| '''; |
| |
| class RecursiveGetters extends LintRule implements NodeLintRule { |
| RecursiveGetters() |
| : super( |
| name: 'recursive_getters', |
| description: _desc, |
| details: _details, |
| group: Group.style); |
| |
| @override |
| void registerNodeProcessors( |
| NodeLintRegistry registry, LinterContext context) { |
| final visitor = _Visitor(this); |
| registry.addFunctionDeclaration(this, visitor); |
| registry.addMethodDeclaration(this, visitor); |
| } |
| } |
| |
| /// Tests if a simple identifier is a recursive getter by looking at its parent. |
| class _RecursiveGetterParentVisitor extends SimpleAstVisitor<bool> { |
| @override |
| bool visitPropertyAccess(PropertyAccess node) => |
| node.target is ThisExpression; |
| |
| @override |
| bool visitSimpleIdentifier(SimpleIdentifier node) { |
| if (node.parent is ArgumentList || |
| node.parent is ConditionalExpression || |
| node.parent is ExpressionFunctionBody || |
| node.parent is ReturnStatement) { |
| return true; |
| } |
| |
| if (node.parent is PropertyAccess) { |
| return node.parent.accept(this); |
| } |
| |
| return false; |
| } |
| } |
| |
| class _Visitor extends SimpleAstVisitor<void> { |
| final LintRule rule; |
| |
| final visitor = _RecursiveGetterParentVisitor(); |
| |
| _Visitor(this.rule); |
| |
| @override |
| void visitFunctionDeclaration(FunctionDeclaration node) { |
| // getters have null arguments, methods have parameters, could be empty. |
| if (node.functionExpression.parameters != null) { |
| return; |
| } |
| |
| final element = node.declaredElement; |
| _verifyElement(node.functionExpression, element); |
| } |
| |
| @override |
| void visitMethodDeclaration(MethodDeclaration node) { |
| // getters have null arguments, methods have parameters, could be empty. |
| if (node.parameters != null) { |
| return; |
| } |
| |
| final element = node.declaredElement; |
| _verifyElement(node.body, element); |
| } |
| |
| void _verifyElement(AstNode node, ExecutableElement element) { |
| final nodes = DartTypeUtilities.traverseNodesInDFS(node); |
| nodes |
| .where((n) => |
| n is SimpleIdentifier && |
| element == n.staticElement && |
| n.accept(visitor)) |
| .forEach(rule.reportLint); |
| } |
| } |