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// Copyright 2014 The Flutter Authors. 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/analysis/results.dart';
import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/dart/ast/visitor.dart';
import 'package:analyzer/dart/element/type.dart';
import '../utils.dart';
import 'analyze.dart';
/// Don't use Future.catchError or Future.onError.
///
/// See https://github.com/flutter/flutter/pull/130662 for more context.
///
/// **BAD:**
///
/// ```dart
/// Future<Object?> doSomething() {
/// return doSomethingAsync().catchError((_) => null);
/// }
///
/// Future<Object?> doSomethingAsync() {
/// return Future<Object>.error(Exception('error'));
/// }
/// ```
///
/// **GOOD:**
///
/// ```dart
/// Future<Object?> doSomething() {
/// return doSomethingAsync().then(
/// (Object? obj) => obj,
/// onError: (_) => null,
/// );
/// }
///
/// Future<Object?> doSomethingAsync() {
/// return Future<Object>.error(Exception('error'));
/// }
/// ```
class AvoidFutureCatchError extends AnalyzeRule {
final Map<ResolvedUnitResult, List<AstNode>> _errors = <ResolvedUnitResult, List<AstNode>>{};
@override
void applyTo(ResolvedUnitResult unit) {
final _Visitor visitor = _Visitor();
unit.unit.visitChildren(visitor);
if (visitor._offendingNodes.isNotEmpty) {
_errors.putIfAbsent(unit, () => <AstNode>[]).addAll(visitor._offendingNodes);
}
}
@override
void reportViolations(String workingDirectory) {
if (_errors.isEmpty) {
return;
}
foundError(<String>[
for (final MapEntry<ResolvedUnitResult, List<AstNode>> entry in _errors.entries)
for (final AstNode node in entry.value)
'${locationInFile(entry.key, node, workingDirectory)}: ${node.parent}',
'\n${bold}Future.catchError and Future.onError are not type safe--instead use Future.then: https://github.com/dart-lang/sdk/issues/51248$reset',
]);
}
@override
String toString() => 'Avoid "Future.catchError" and "Future.onError"';
}
class _Visitor extends RecursiveAstVisitor<void> {
_Visitor();
final List<AstNode> _offendingNodes = <AstNode>[];
@override
void visitMethodInvocation(MethodInvocation node) {
if (node.methodName.name != 'onError' && node.methodName.name != 'catchError') {
return;
}
final DartType? targetType = node.realTarget?.staticType;
if (targetType == null || !targetType.isDartAsyncFuture) {
return;
}
_offendingNodes.add(node);
}
}