augmentation support for always_declare_return_types

Fixes: https://github.com/dart-lang/linter/issues/4951

Change-Id: I451195fd32ffd69f5e88c3587dc5bc0a28815fc3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/363943
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Phil Quitslund <[email protected]>

Author: pq

pkg/linter/lib/src/rules/always_declare_return_types.dart

@@ -7,6 +7,7 @@ import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 
 import '../analyzer.dart';
+import '../extensions.dart';
 
 const _desc = r'Declare method return types.';
 
@@ -88,7 +89,7 @@ class _Visitor extends SimpleAstVisitor<void> {
 
   @override
   void visitFunctionDeclaration(FunctionDeclaration node) {
-    if (!node.isSetter && node.returnType == null) {
+    if (!node.isSetter && node.returnType == null && !node.isAugmentation) {
       rule.reportLintForToken(node.name,
           arguments: [node.name.lexeme], errorCode: functionCode);
     }
@@ -106,7 +107,8 @@ class _Visitor extends SimpleAstVisitor<void> {
   void visitMethodDeclaration(MethodDeclaration node) {
     if (!node.isSetter &&
         node.returnType == null &&
-        node.name.type != TokenType.INDEX_EQ) {
+        node.name.type != TokenType.INDEX_EQ &&
+        !node.isAugmentation) {
       rule.reportLintForToken(node.name,
           arguments: [node.name.lexeme], errorCode: methodCode);
     }

pkg/linter/test/rules/all.dart

@@ -4,6 +4,7 @@
 
 // ignore_for_file: library_prefixes
 
+import 'always_declare_return_types_test.dart' as always_declare_return_types;
 import 'always_specify_types_test.dart' as always_specify_types;
 import 'always_use_package_imports_test.dart' as always_use_package_imports;
 import 'annotate_overrides_test.dart' as annotate_overrides;
@@ -267,6 +268,7 @@ import 'valid_regexps_test.dart' as valid_regexps;
 import 'void_checks_test.dart' as void_checks;
 
 void main() {
+  always_declare_return_types.main();
   always_specify_types.main();
   always_use_package_imports.main();
   annotate_overrides.main();

pkg/linter/test/rules/always_declare_return_types_test.dart

@@ -0,0 +1,135 @@
+// Copyright (c) 2024, 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(AlwaysDeclareReturnTypesTest);
+  });
+}
+
+@reflectiveTest
+class AlwaysDeclareReturnTypesTest extends LintRuleTest {
+  @override
+  String get lintRule => 'always_declare_return_types';
+
+  test_augmentationClass() async {
+    var a = newFile('$testPackageLibPath/a.dart', r'''
+import augment 'b.dart';
+
+class A { }
+''');
+
+    var b = newFile('$testPackageLibPath/b.dart', r'''
+augment library 'a.dart';
+
+augment class A {
+  f() { }
+}
+''');
+
+    result = await resolveFile(a.path);
+    await assertNoDiagnosticsIn(errors);
+
+    result = await resolveFile(b.path);
+    await assertDiagnosticsIn(errors, [
+      lint(47, 1),
+    ]);
+  }
+
+  test_augmentationTopLevelFunction() async {
+    var a = newFile('$testPackageLibPath/a.dart', r'''
+import augment 'b.dart';
+''');
+
+    var b = newFile('$testPackageLibPath/b.dart', r'''
+augment library 'a.dart';
+
+f() { }
+''');
+
+    result = await resolveFile(a.path);
+    await assertNoDiagnosticsIn(errors);
+
+    result = await resolveFile(b.path);
+    await assertDiagnosticsIn(errors, [
+      lint(27, 1),
+    ]);
+  }
+
+  /// Augmentation target chain variations tested in `augmentedTopLevelFunction{*}`.
+  test_augmentedMethod() async {
+    var a = newFile('$testPackageLibPath/a.dart', r'''
+import augment 'b.dart';
+
+class A {
+  f() { }
+}
+''');
+
+    var b = newFile('$testPackageLibPath/b.dart', r'''
+augment library 'a.dart';
+
+augment class A {
+  augment f() { }
+}
+''');
+
+    result = await resolveFile(a.path);
+    await assertDiagnosticsIn(errors, [
+      lint(38, 1),
+    ]);
+
+    result = await resolveFile(b.path);
+    await assertNoDiagnosticsIn(errors);
+  }
+
+  test_augmentedTopLevelFunction() async {
+    var a = newFile('$testPackageLibPath/a.dart', r'''
+import augment 'b.dart';
+
+f() { }
+''');
+
+    var b = newFile('$testPackageLibPath/b.dart', r'''
+augment library 'a.dart';
+
+augment f() { }
+''');
+
+    result = await resolveFile(a.path);
+    await assertDiagnosticsIn(errors, [
+      lint(26, 1),
+    ]);
+
+    result = await resolveFile(b.path);
+    await assertNoDiagnosticsIn(errors);
+  }
+
+  test_augmentedTopLevelFunction_chain() async {
+    var a = newFile('$testPackageLibPath/a.dart', r'''
+import augment 'b.dart';
+
+f() { }
+''');
+
+    var b = newFile('$testPackageLibPath/b.dart', r'''
+augment library 'a.dart';
+
+augment dynamic f() { }
+augment f() { }
+''');
+
+    result = await resolveFile(a.path);
+    await assertDiagnosticsIn(errors, [
+      lint(26, 1),
+    ]);
+
+    result = await resolveFile(b.path);
+    await assertNoDiagnosticsIn(errors);
+  }
+}