Add avoid_direct_collection_equality_checks lint

packages/leancode_lint/CHANGELOG.md

@@ -1,3 +1,8 @@
+# Unreleased
+
+- Add new custom lints:
+  - [`avoid_direct_collection_equality_checks`](https://github.com/leancodepl/flutter_corelibrary/tree/master/packages/leancode_lint#avoid_direct_collection_equality_checks)
+
 # 24.0.0
 
 - Add new custom lints:
@@ -93,7 +98,7 @@
 - Remove the following lints which have been removed from Dart:
   - [`package_api_docs`](https://dart.dev/tools/linter-rules/package_api_docs)
   - [`unsafe_html`](https://dart.dev/tools/linter-rules/unsafe_html)
-- Disable the [`require_trailing_commas`](https://dart.dev/tools/linter-rules/require_trailing_commas) lint as it conflicts with Dart 3.7 formatter (https://github.com/dart-lang/sdk/issues/60119).
+- Disable the [`require_trailing_commas`](https://dart.dev/tools/linter-rules/require_trailing_commas) lint as it conflicts with Dart 3.7 formatter (<https://github.com/dart-lang/sdk/issues/60119>).
 
 # 15.1.0
 

packages/leancode_lint/README.md

@@ -256,6 +256,60 @@ None.
 
 </details>
 
+<details>
+<summary><code>avoid_direct_collection_equality_checks</code></summary>
+
+### `avoid_direct_collection_equality_checks`
+
+**AVOID** comparing collections directly with `==` or `!=`.
+
+For `List`, `Set`, and `Map`, `==` compares identity (reference equality), not
+contents, so `[1, 2] == [1, 2]` is `false`. Use a content-equality helper
+instead.
+
+The rule offers three quick fixes: one rewriting the comparison to Flutter's
+`listEquals`/`setEquals`/`mapEquals` (from `package:flutter/foundation.dart`),
+one to `package:collection`'s `ListEquality`/`SetEquality`/`MapEquality`, and one
+to `identical` for the cases where an identity comparison is actually intended.
+The `package:collection` fix is only offered when the equality class is reachable
+through a direct dependency — either `package:collection` itself or a package
+that re-exports it — and imports it via that dependency. The content-equality
+fixes add the required import, and all fixes negate the result for `!=`.
+
+**BAD:**
+
+```dart
+bool sameItems(List<int> a, List<int> b) {
+  return a == b;
+}
+```
+
+**GOOD:**
+
+```dart
+import 'package:flutter/foundation.dart';
+
+bool sameItems(List<int> a, List<int> b) {
+  return listEquals(a, b);
+}
+```
+
+**GOOD:**
+
+```dart
+import 'package:collection/collection.dart';
+
+bool sameItems(List<int> a, List<int> b) {
+  return const ListEquality<int>().equals(a, b);
+}
+```
+
+#### Configuration
+
+None.
+
+</details>
+
 <details>
 <summary><code>bloc_related_class_naming</code></summary>
 

packages/leancode_lint/lib/plugin.dart

@@ -7,6 +7,7 @@ import 'package:leancode_lint/src/assists/convert_record_into_nominal_type.dart'
 import 'package:leancode_lint/src/lints/add_cubit_suffix_for_cubits.dart';
 import 'package:leancode_lint/src/lints/avoid_catch_error.dart';
 import 'package:leancode_lint/src/lints/avoid_conditional_hooks.dart';
+import 'package:leancode_lint/src/lints/avoid_direct_collection_equality_checks.dart';
 import 'package:leancode_lint/src/lints/avoid_single_child_in_multi_child_widget.dart';
 import 'package:leancode_lint/src/lints/bloc_related_class_naming.dart';
 import 'package:leancode_lint/src/lints/bloc_subclasses_naming.dart';
@@ -64,6 +65,19 @@ final class LeanCodeLintPlugin extends Plugin {
       )
       ..registerWarningRule(AvoidCatchError())
       ..registerWarningRule(AvoidConditionalHooks())
+      ..registerWarningRule(AvoidDirectCollectionEqualityChecks())
+      ..registerFixForRule(
+        AvoidDirectCollectionEqualityChecks.code,
+        ReplaceWithFlutterFoundationEqualsFix.new,
+      )
+      ..registerFixForRule(
+        AvoidDirectCollectionEqualityChecks.code,
+        ReplaceWithCollectionPackageEqualityFix.new,
+      )
+      ..registerFixForRule(
+        AvoidDirectCollectionEqualityChecks.code,
+        ReplaceWithIdenticalFix.new,
+      )
       ..registerWarningRule(HookWidgetDoesNotUseHooks())
       ..registerFixForRule(
         HookWidgetDoesNotUseHooks.code,