issue-93. added new consider_making_a_member_privat rule

Author: shaark

example/analysis_options.yaml

@@ -20,6 +20,7 @@ custom_lint:
     - double_literal_format
     - avoid_unnecessary_type_assertions
     - avoid_debug_print_in_release
+    - consider_making_a_member_private
     - avoid_using_api:
       severity: info
       entries:

lib/analysis_options.yaml

@@ -52,6 +52,7 @@ custom_lint:
     - avoid_unused_parameters
     - avoid_debug_print_in_release
     - avoid_final_with_getter
+    - consider_making_a_member_private
 
     - cyclomatic_complexity:
       max_complexity: 10

lib/solid_lints.dart

@@ -13,6 +13,7 @@ import 'package:solid_lints/src/lints/avoid_unnecessary_type_casts/avoid_unneces
 import 'package:solid_lints/src/lints/avoid_unrelated_type_assertions/avoid_unrelated_type_assertions_rule.dart';
 import 'package:solid_lints/src/lints/avoid_unused_parameters/avoid_unused_parameters_rule.dart';
 import 'package:solid_lints/src/lints/avoid_using_api/avoid_using_api_rule.dart';
+import 'package:solid_lints/src/lints/consider_making_a_member_private/consider_making_a_member_private_rule.dart';
 import 'package:solid_lints/src/lints/cyclomatic_complexity/cyclomatic_complexity_rule.dart';
 import 'package:solid_lints/src/lints/double_literal_format/double_literal_format_rule.dart';
 import 'package:solid_lints/src/lints/function_lines_of_code/function_lines_of_code_rule.dart';
@@ -65,6 +66,7 @@ class _SolidLints extends PluginBase {
       AvoidDebugPrintInReleaseRule.createRule(configs),
       PreferEarlyReturnRule.createRule(configs),
       AvoidFinalWithGetterRule.createRule(configs),
+      ConsiderMakingAMemberPrivateRule.createRule(configs),
     ];
 
     // Return only enabled rules

lib/src/lints/consider_making_a_member_private/consider_making_a_member_private_rule.dart

@@ -0,0 +1,78 @@
+import 'package:analyzer/error/listener.dart';
+import 'package:custom_lint_builder/custom_lint_builder.dart';
+import 'package:solid_lints/src/lints/consider_making_a_member_private/visitor/consider_making_a_member_private_visitor.dart';
+import 'package:solid_lints/src/models/rule_config.dart';
+import 'package:solid_lints/src/models/solid_lint_rule.dart';
+
+/// Warns about public method, field if its not used outside.
+///
+/// ### Example:
+/// #### BAD:
+/// class X {
+/// only used internally
+///  void x() {
+///    ...
+///  }
+///}
+/// #### Good:
+/// class X {
+/// only used internally
+///  void _x() {
+///    ...
+///  }
+///}
+/// #### Good:
+/// class X {
+///
+///  void x() {
+///    ...
+///  }
+///}
+///
+/// class Y {
+///
+/// final x = X();
+///
+/// void y(){
+/// x.x();
+/// }
+/// }
+class ConsiderMakingAMemberPrivateRule extends SolidLintRule {
+  /// This lint rule represents
+  /// the error whether we use public method, field if its not used outside.
+  static const String lintName = 'consider_making_a_member_private';
+
+  ConsiderMakingAMemberPrivateRule._(super.config);
+
+  /// Creates a new instance of [ConsiderMakingAMemberPrivateRule]
+  /// based on the lint configuration.
+  factory ConsiderMakingAMemberPrivateRule.createRule(
+    CustomLintConfigs configs,
+  ) {
+    final rule = RuleConfig(
+      configs: configs,
+      name: lintName,
+      problemMessage: (_) => 'Consider making a member privat',
+    );
+
+    return ConsiderMakingAMemberPrivateRule._(rule);
+  }
+
+  @override
+  void run(
+    CustomLintResolver resolver,
+    ErrorReporter reporter,
+    CustomLintContext context,
+  ) {
+    context.registry.addCompilationUnit((node) {
+      final visitor = ConsiderMakingAMemberPrivateVisitor(node);
+      node.visitChildren(visitor);
+
+      final unusedMembers = visitor.unusedPublicMembers;
+
+      for (final member in unusedMembers) {
+        reporter.atNode(member, code);
+      }
+    });
+  }
+}

lib/src/lints/consider_making_a_member_private/visitor/consider_making_a_member_private_visitor.dart

@@ -0,0 +1,109 @@
+// MIT License
+//
+// Copyright (c) 2020-2021 Dart Code Checker team
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/visitor.dart';
+
+/// The AST visitor that will find lines with code.
+class ConsiderMakingAMemberPrivateVisitor extends RecursiveAstVisitor<void> {
+  final CompilationUnit _node;
+
+  final _unusedPublicMembers = <ClassMember>{};
+
+  /// Returns public members that are not used as representatives of the class.
+  Iterable<ClassMember> get unusedPublicMembers => _unusedPublicMembers;
+
+  /// Creates a new instance of [ConsiderMakingAMemberPrivateVisitor].
+  ConsiderMakingAMemberPrivateVisitor(this._node);
+
+  @override
+  void visitClassDeclaration(ClassDeclaration node) {
+    final classMembers = node.members.where((member) {
+      if (member is MethodDeclaration || member is FieldDeclaration) {
+        final name = _getMemberName(member);
+        return name != null && !_isPrivate(name);
+      }
+      return false;
+    }).toList();
+
+    for (final member in classMembers) {
+      final memberName = _getMemberName(member)!;
+      if (!_isUsedOutsideClass(memberName, node)) {
+        _unusedPublicMembers.add(member);
+      }
+    }
+
+    super.visitClassDeclaration(node);
+  }
+
+  bool _isPrivate(String name) => name.startsWith('_');
+
+  String? _getMemberName(ClassMember member) {
+    if (member is MethodDeclaration) return member.declaredElement?.name;
+    if (member is FieldDeclaration) {
+      final fields = member.fields.variables;
+      return fields.isNotEmpty ? fields.first.declaredElement?.name : null;
+    }
+    return null;
+  }
+
+  bool _isUsedOutsideClass(String memberName, ClassDeclaration classNode) {
+    bool isUsedOutside = false;
+
+    _node.visitChildren(
+      _PublicMemberUsageVisitor(
+        memberName: memberName,
+        classNode: classNode,
+        onUsageFound: () {
+          isUsedOutside = true;
+        },
+      ),
+    );
+
+    return isUsedOutside;
+  }
+}
+
+class _PublicMemberUsageVisitor extends RecursiveAstVisitor<void> {
+  final String memberName;
+  final ClassDeclaration classNode;
+  final Function() onUsageFound;
+
+  _PublicMemberUsageVisitor({
+    required this.memberName,
+    required this.classNode,
+    required this.onUsageFound,
+  });
+
+  @override
+  void visitSimpleIdentifier(SimpleIdentifier identifier) {
+    if (identifier.name == memberName) {
+      final parentClass = identifier.thisOrAncestorOfType<ClassDeclaration>();
+      if (parentClass != classNode) {
+        onUsageFound();
+      }
+    }
+
+    super.visitSimpleIdentifier(identifier);
+  }
+}

lint_test/alphabetize_by_type_test/alphabetize_by_type_test.dart

@@ -1,4 +1,4 @@
-// ignore_for_file: unused_field
+// ignore_for_file: unused_field, consider_making_a_member_private
 // ignore_for_file: unused_element
 // ignore_for_file: prefer_match_file_name
 

lint_test/analysis_options.yaml

@@ -58,3 +58,4 @@ custom_lint:
     - prefer_match_file_name
     - proper_super_calls
     - avoid_final_with_getter
+    - consider_making_a_member_private

lint_test/avoid_final_with_getter_test.dart

@@ -1,4 +1,4 @@
-// ignore_for_file: type_annotate_public_apis, prefer_match_file_name, unused_local_variable
+// ignore_for_file: type_annotate_public_apis, prefer_match_file_name, unused_local_variable, consider_making_a_member_private
 
 /// Check final private field with getter fail
 /// `avoid_final_with_getter`

lint_test/avoid_global_state_test.dart

@@ -1,4 +1,4 @@
-// ignore_for_file: type_annotate_public_apis, prefer_match_file_name, unused_local_variable
+// ignore_for_file: type_annotate_public_apis, prefer_match_file_name, unused_local_variable, consider_making_a_member_private
 
 /// Check global mutable variable fail
 /// `avoid_global_state`

lint_test/avoid_late_keyword/allow_initialized/avoid_late_keyword_allow_initialized_test.dart

@@ -1,4 +1,4 @@
-// ignore_for_file: prefer_const_declarations, unused_local_variable, prefer_match_file_name
+// ignore_for_file: prefer_const_declarations, unused_local_variable, prefer_match_file_name, consider_making_a_member_private
 // ignore_for_file: avoid_global_state
 
 abstract class Animation {}