Excluded methods named 'copyWith' from `number_of_parameter…

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 - Added `avoid_using_debug_print` rule
 - Fixed an issue with no_magic_number lint
+- Excluded methods/functions named 'copyWith' from `number_of_parameters` lint
 
 ## 0.1.4
 

lib/src/lints/number_of_parameters/number_of_parameters_metric.dart

@@ -7,7 +7,7 @@ import 'package:solid_lints/src/models/solid_lint_rule.dart';
 
 /// A number of parameters metric which checks whether we didn't exceed
 /// the maximum allowed number of parameters for a function, method or
-/// constructor.
+/// constructor. Methods named 'copyWith' are excluded.
 ///
 /// ### Example:
 ///
@@ -35,6 +35,27 @@ import 'package:solid_lints/src/models/solid_lint_rule.dart';
 ///   void method(a, b) {} // OK
 /// }
 /// ```
+///
+/// ### Allowed
+/// ```dart
+/// UserDto copyWith({
+///   String? email,
+///   String? firstName,
+///   String? id,
+///   String? imageUrl,
+///   String? lastName,
+///   String? phone,
+/// }) {
+///   return UserDto(
+///     email: email ?? this.email,
+///     firstName: firstName ?? this.firstName,
+///     id: id ?? this.id,
+///     imageUrl: imageUrl ?? this.imageUrl,
+///     lastName: lastName ?? this.lastName,
+///     phone: phone ?? this.phone,
+///   );
+/// }
+/// ```
 class NumberOfParametersMetric
     extends SolidLintRule<NumberOfParametersParameters> {
   /// The [LintCode] of this lint rule that represents the error if number of
@@ -58,13 +79,20 @@ class NumberOfParametersMetric
     return NumberOfParametersMetric._(rule);
   }
 
+  bool _hasAllowedName(String name) {
+    return name == 'copyWith';
+  }
+
   @override
   void run(
     CustomLintResolver resolver,
     ErrorReporter reporter,
     CustomLintContext context,
   ) {
     context.registry.addDeclaration((node) {
+      if (node is! MethodDeclaration && node is! FunctionDeclaration) {
+        return;
+      }
       final parameters = switch (node) {
         (final MethodDeclaration node) =>
           node.parameters?.parameters.length ?? 0,
@@ -73,11 +101,21 @@ class NumberOfParametersMetric
         _ => 0,
       };
 
-      if (parameters > config.parameters.maxParameters) {
-        reporter.reportErrorForOffset(
+      final isMethod = node is MethodDeclaration;
+
+      final declaredElement = node.declaredElement;
+      if (declaredElement == null) {
+        return;
+      }
+      final shouldInclude = switch (isMethod) {
+        true => !_hasAllowedName(node.declaredElement?.name ?? ''),
+        false => true,
+      };
+
+      if (parameters > config.parameters.maxParameters && shouldInclude) {
+        reporter.reportErrorForElement(
           code,
-          node.firstTokenAfterCommentAndMetadata.offset,
-          node.end,
+          declaredElement,
         );
       }
     });

lint_test/number_of_parameters_test.dart

@@ -1,7 +1,70 @@
+// ignore_for_file: public_member_api_docs, sort_constructors_first
+// ignore_for_file: prefer_match_file_name
 /// Check number of parameters fail
 ///
 /// `number_of_parameters: max_parameters`
-/// expect_lint: number_of_parameters
+
+// expect_lint: number_of_parameters
 String numberOfParameters(String a, String b, String c) {
   return a + b + c;
 }
+
+// expect_lint: number_of_parameters
+String copyWith(String a, String b, String c) {
+  return a + b + c;
+}
+
+class UserDto {
+  final String email;
+  final String firstName;
+  final String id;
+  final String imageUrl;
+  final String lastName;
+
+  final String phone;
+  const UserDto({
+    required this.id,
+    required this.firstName,
+    required this.lastName,
+    required this.imageUrl,
+    required this.email,
+    required this.phone,
+  });
+
+  UserDto copyWith({
+    String? email,
+    String? firstName,
+    String? id,
+    String? imageUrl,
+    String? lastName,
+    String? phone,
+  }) {
+    return UserDto(
+      email: email ?? this.email,
+      firstName: firstName ?? this.firstName,
+      id: id ?? this.id,
+      imageUrl: imageUrl ?? this.imageUrl,
+      lastName: lastName ?? this.lastName,
+      phone: phone ?? this.phone,
+    );
+  }
+
+// expect_lint: number_of_parameters
+  UserDto test({
+    String? email,
+    String? firstName,
+    String? id,
+    String? imageUrl,
+    String? lastName,
+    String? phone,
+  }) {
+    return UserDto(
+      email: email ?? this.email,
+      firstName: firstName ?? this.firstName,
+      id: id ?? this.id,
+      imageUrl: imageUrl ?? this.imageUrl,
+      lastName: lastName ?? this.lastName,
+      phone: phone ?? this.phone,
+    );
+  }
+}