add lint use_string_in_part_of_directives (dart-lang/linter#3567)

* add lint use_string_in_part_of_directives

* migrate test to reflective_test_loader style

example/all.yaml

@@ -203,6 +203,7 @@ linter:
     - use_rethrow_when_possible
     - use_setters_to_change_properties
     - use_string_buffers
+    - use_string_in_part_of_directives
     - use_super_parameters
     - use_test_throws_matchers
     - use_to_and_as_if_applicable

lib/src/rules.dart

@@ -208,6 +208,7 @@ import 'rules/use_raw_strings.dart';
 import 'rules/use_rethrow_when_possible.dart';
 import 'rules/use_setters_to_change_properties.dart';
 import 'rules/use_string_buffers.dart';
+import 'rules/use_string_in_part_of_directives.dart';
 import 'rules/use_super_parameters.dart';
 import 'rules/use_test_throws_matchers.dart';
 import 'rules/use_to_and_as_if_applicable.dart';
@@ -424,6 +425,7 @@ void registerLintRules({bool inTestMode = false}) {
     ..register(UseRawStrings())
     ..register(UseSettersToChangeAProperty())
     ..register(UseStringBuffers())
+    ..register(UseStringInPartOfDirectives())
     ..register(UseSuperParameters())
     ..register(UseTestThrowsMatchers())
     ..register(UseToAndAsIfApplicable())

lib/src/rules/use_string_in_part_of_directives.dart

@@ -0,0 +1,62 @@
+// 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 '../analyzer.dart';
+
+const _desc = r'Use string in part of directives.';
+
+const _details = r'''
+
+From [effective dart](https://dart.dev/guides/language/effective-dart/usage#do-use-strings-in-part-of-directives):
+
+**DO** use strings in `part of` directives.
+
+**BAD:**
+
+```dart
+part of my_library;
+```
+
+**GOOD:**
+
+```dart
+part of '../../my_library.dart';
+```
+
+''';
+
+class UseStringInPartOfDirectives extends LintRule {
+  UseStringInPartOfDirectives()
+      : super(
+          name: 'use_string_in_part_of_directives',
+          description: _desc,
+          details: _details,
+          group: Group.style,
+        );
+
+  @override
+  void registerNodeProcessors(
+    NodeLintRegistry registry,
+    LinterContext context,
+  ) {
+    var visitor = _Visitor(this);
+    registry.addPartOfDirective(this, visitor);
+  }
+}
+
+class _Visitor extends SimpleAstVisitor<void> {
+  _Visitor(this.rule);
+
+  final LintRule rule;
+
+  @override
+  void visitPartOfDirective(PartOfDirective node) {
+    if (node.libraryName != null) {
+      rule.reportLint(node);
+    }
+  }
+}

test/rule_test_support.dart

@@ -237,8 +237,10 @@ class PubPackageResolutionTest extends _ContextResolutionTest {
   /// The path that is not in [workspaceRootPath], contains external packages.
   String get packagesRootPath => '/packages';
 
+  String get testFileName => 'test.dart';
+
   @override
-  String get testFilePath => '$testPackageLibPath/test.dart';
+  String get testFilePath => '$testPackageLibPath/$testFileName';
 
   String? get testPackageLanguageVersion => null;
 

test/rules/use_string_in_part_of_directives.dart

@@ -0,0 +1,46 @@
+// Copyright (c) 2021, 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:test_reflective_loader/test_reflective_loader.dart';
+
+import '../rule_test_support.dart';
+
+main() {
+  defineReflectiveSuite(() {
+    defineReflectiveTests(UseStringInPartOfDirectivesTest);
+  });
+}
+
+@reflectiveTest
+class UseStringInPartOfDirectivesTest extends LintRuleTest {
+  @override
+  bool get addMetaPackageDep => true;
+
+  @override
+  String get lintRule => 'use_string_in_part_of_directives';
+
+  test_part_of_with_string() async {
+    newFile2('$testPackageRootPath/lib/lib.dart', '''
+part '$testFileName';
+''');
+    await assertNoDiagnostics(r'''
+part of 'lib.dart';
+''');
+  }
+
+  test_part_of_with_library_name() async {
+    newFile2('$testPackageRootPath/lib/lib.dart', '''
+library lib;
+part '$testFileName';
+''');
+    await assertDiagnostics(
+      r'''
+part of lib;
+''',
+      [
+        lint('use_string_in_part_of_directives', 0, 12),
+      ],
+    );
+  }
+}