add combinators_ordering (#3468)

* add combinators_ordering

* address review comments

example/all.yaml

@@ -56,6 +56,7 @@ linter:
     - cascade_invocations
     - cast_nullable_to_non_nullable
     - close_sinks
+    - combinators_ordering
     - comment_references
     - conditional_uri_does_not_exist
     - constant_identifier_names

lib/src/rules.dart

@@ -58,6 +58,7 @@ import 'rules/cancel_subscriptions.dart';
 import 'rules/cascade_invocations.dart';
 import 'rules/cast_nullable_to_non_nullable.dart';
 import 'rules/close_sinks.dart';
+import 'rules/combinators_ordering.dart';
 import 'rules/comment_references.dart';
 import 'rules/conditional_uri_does_not_exist.dart';
 import 'rules/constant_identifier_names.dart';
@@ -271,6 +272,7 @@ void registerLintRules({bool inTestMode = false}) {
     ..register(CascadeInvocations())
     ..register(CastNullableToNonNullable())
     ..register(CloseSinks())
+    ..register(CombinatorsOrdering())
     ..register(CommentReferences())
     ..register(ConditionalUriDoesNotExist())
     ..register(ConstantIdentifierNames())

lib/src/rules/combinators_ordering.dart

@@ -0,0 +1,69 @@
+// Copyright (c) 2022, 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:collection/collection.dart';
+
+import '../analyzer.dart';
+
+const _desc = r'Sort combinator names alphabetically.';
+
+const _details = r'''
+
+**DO** sort combinator names alphabetically.
+
+**BAD:**
+```dart
+import 'a.dart' show B, A hide D, C;
+export 'a.dart' show B, A hide D, C;
+```
+
+**GOOD:**
+```dart
+import 'a.dart' show A, B hide C, D;
+export 'a.dart' show A, B hide C, D;
+```
+
+''';
+
+class CombinatorsOrdering extends LintRule {
+  CombinatorsOrdering()
+      : super(
+          name: 'combinators_ordering',
+          description: _desc,
+          details: _details,
+          group: Group.style,
+        );
+
+  @override
+  void registerNodeProcessors(
+    NodeLintRegistry registry,
+    LinterContext context,
+  ) {
+    var visitor = _Visitor(this);
+    registry.addHideCombinator(this, visitor);
+    registry.addShowCombinator(this, visitor);
+  }
+}
+
+class _Visitor extends SimpleAstVisitor<void> {
+  _Visitor(this.rule);
+
+  final LintRule rule;
+
+  @override
+  void visitHideCombinator(HideCombinator node) {
+    if (!node.hiddenNames.map((e) => e.name).isSorted()) {
+      rule.reportLint(node);
+    }
+  }
+
+  @override
+  void visitShowCombinator(ShowCombinator node) {
+    if (!node.shownNames.map((e) => e.name).isSorted()) {
+      rule.reportLint(node);
+    }
+  }
+}

test_data/rules/combinators_ordering.dart

@@ -0,0 +1,17 @@
+// Copyright (c) 2022, 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.
+
+// test w/ `dart test -N combinators_ordering`
+
+import 'dart:math' as m1 show max, min; // OK
+import 'dart:math' as m2 show min, max; // LINT
+
+export 'dart:math' show max, min; // OK
+export 'dart:math' show min, max; // LINT
+
+import 'dart:math' as m3 hide max, min; // OK
+import 'dart:math' as m4 hide min, max; // LINT
+
+export 'dart:math' hide max, min; // OK
+export 'dart:math' hide min, max; // LINT