| // Copyright (c) 2017, 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 '../analyzer.dart'; |
| import '../util/dart_type_utilities.dart'; |
| |
| const _desc = r'Use rethrow to rethrow a caught exception.'; |
| |
| const _details = r''' |
| |
| **DO** use rethrow to rethrow a caught exception. |
| |
| As Dart provides rethrow as a feature, it should be used to improve terseness |
| and readability. |
| |
| **BAD:** |
| ``` |
| try { |
| somethingRisky(); |
| } catch(e) { |
| if (!canHandle(e)) throw e; |
| handle(e); |
| } |
| ``` |
| |
| **GOOD:** |
| ``` |
| try { |
| somethingRisky(); |
| } catch(e) { |
| if (!canHandle(e)) rethrow; |
| handle(e); |
| } |
| ``` |
| |
| '''; |
| |
| class UseRethrowWhenPossible extends LintRule implements NodeLintRule { |
| UseRethrowWhenPossible() |
| : super( |
| name: 'use_rethrow_when_possible', |
| description: _desc, |
| details: _details, |
| group: Group.style); |
| |
| @override |
| void registerNodeProcessors( |
| NodeLintRegistry registry, LinterContext context) { |
| final visitor = _Visitor(this); |
| registry.addThrowExpression(this, visitor); |
| } |
| } |
| |
| class _Visitor extends SimpleAstVisitor<void> { |
| final LintRule rule; |
| |
| _Visitor(this.rule); |
| |
| @override |
| void visitThrowExpression(ThrowExpression node) { |
| final element = |
| DartTypeUtilities.getCanonicalElementFromIdentifier(node.expression); |
| if (element != null) { |
| final catchClause = node.thisOrAncestorOfType<CatchClause>(); |
| final exceptionParameter = |
| DartTypeUtilities.getCanonicalElementFromIdentifier( |
| catchClause?.exceptionParameter); |
| if (element == exceptionParameter) { |
| rule.reportLint(node); |
| } |
| } |
| } |
| } |