feat(lint): implement state_base_class_suffix rule

README.md

@@ -13,4 +13,5 @@ The example folder contains a dart project to unit test the rules. (see custom_l
 - [avoid_public_properties_on_bloc_and_cubit](docs/rules/avoid_public_properties_on_bloc_and_cubit.md)
 - [prefer_multi_bloc_listener](docs/rules/prefer_multi_bloc_listener.md)
 - [prefer_multi_bloc_provider](docs/rules/prefer_multi_bloc_provider.md)
-- [prefer_multi_repository_provider](docs/rules/prefer_multi_repository_provider.md)
+- [prefer_multi_repository_provider](docs/rules/prefer_multi_repository_provider.md)
+- [state_base_class_suffix](docs/rules/state_base_class_suffix.md) 

docs/rules/state_base_class_suffix.md

@@ -0,0 +1,28 @@
+state_base_class_suffix
+===
+severity: WARNING
+
+The base state class should always be suffixed by `State`.
+
+## Example:
+
+❌ **BAD**:
+
+```dart
+@immutable
+sealed class HomepageData {}
+
+final class HomepageInitial extends HomepageData {}
+```
+
+✅ **GOOD**:
+
+```dart
+sealed class HomepageState {}
+
+final class HomepageInitial extends HomepageState {}
+```
+
+## Additional Resources
+
+- [Bloc Library Documentation: Naming Conventions / State Conventions](https://bloclibrary.dev/naming-conventions/#state-conventions)

example/lib/lint_rules/state_base_class_suffix_lint_rule_test_bloc.dart

@@ -0,0 +1,23 @@
+import 'package:bloc/bloc.dart';
+import 'package:meta/meta.dart';
+
+class StateBaseClassSuffixLintRuleTestBloc extends Bloc<
+    StateBaseClassSuffixLintRuleTestEvent,
+// expect_lint: state_base_class_suffix
+    StateBaseClassSuffixLintRuleTestError> {
+  StateBaseClassSuffixLintRuleTestBloc()
+      : super(StateBaseClassSuffixLintRuleTestInitial()) {
+    on<StateBaseClassSuffixLintRuleTestEvent>((event, emit) {
+      // TODO: implement event handler
+    });
+  }
+}
+
+@immutable
+sealed class StateBaseClassSuffixLintRuleTestEvent {}
+
+@immutable
+sealed class StateBaseClassSuffixLintRuleTestError {}
+
+final class StateBaseClassSuffixLintRuleTestInitial
+    extends StateBaseClassSuffixLintRuleTestError {}

example/lib/lint_rules/state_base_class_suffix_lint_rule_test_cubit.dart

@@ -0,0 +1,14 @@
+import 'package:bloc/bloc.dart';
+import 'package:meta/meta.dart';
+
+class StateBaseClassSuffixLintRuleTestCubit // expect_lint: state_base_class_suffix
+    extends Cubit<StateBaseClassSuffixLintRuleTest> {
+  StateBaseClassSuffixLintRuleTestCubit()
+      : super(StateBaseClassSuffixLintRuleTestInitial());
+}
+
+@immutable
+sealed class StateBaseClassSuffixLintRuleTest {}
+
+final class StateBaseClassSuffixLintRuleTestInitial
+    extends StateBaseClassSuffixLintRuleTest {}

lib/bloc_lint.dart

@@ -3,6 +3,7 @@ import 'package:bloc_lint/lint_rules/avoid_public_properties_on_bloc_and_cubit_l
 import 'package:bloc_lint/lint_rules/prefer_multi_bloc_listener_lint_rule.dart';
 import 'package:bloc_lint/lint_rules/prefer_multi_bloc_provider_lint_rule.dart';
 import 'package:bloc_lint/lint_rules/prefer_multi_repository_provider_lint_rule.dart';
+import 'package:bloc_lint/lint_rules/state_base_class_suffix.dart';
 import 'package:custom_lint_builder/custom_lint_builder.dart';
 
 PluginBase createPlugin() => _BlocLintPlugin();
@@ -15,5 +16,6 @@ class _BlocLintPlugin extends PluginBase {
         const PreferMultiBlocListenerLintRule(),
         const PreferMultiBlocProviderLintRule(),
         const PreferMultiRepositoryProviderLintRule(),
+        const StateBaseClassSuffix(),
       ];
 }

lib/lint_rules/state_base_class_suffix.dart

@@ -0,0 +1,58 @@
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/element/type.dart';
+import 'package:analyzer/error/error.dart';
+import 'package:analyzer/error/listener.dart';
+import 'package:bloc_lint/bloc_lint_constants.dart';
+import 'package:custom_lint_builder/custom_lint_builder.dart';
+
+class StateBaseClassSuffix extends DartLintRule {
+  const StateBaseClassSuffix()
+      : super(
+          code: const LintCode(
+            name: 'state_base_class_suffix',
+            problemMessage:
+                '''The base state class should always be suffixed by 'State'.''',
+            errorSeverity: ErrorSeverity.WARNING,
+          ),
+        );
+
+  static const _ignoredType = [
+    'int',
+    'double',
+    'num',
+    'String',
+    'bool',
+    'List',
+    'Set',
+    'Map',
+  ];
+
+  @override
+  void run(
+    CustomLintResolver resolver,
+    ErrorReporter reporter,
+    CustomLintContext context,
+  ) {
+    context.registry.addExtendsClause((node) {
+      final superClass = node.superclass;
+      TypeAnnotation? stateNode;
+
+      if (superClass.element?.name == BlocLintConstants.cubitClass) {
+        stateNode = superClass.typeArguments?.arguments[0];
+      } else if (superClass.element?.name == BlocLintConstants.blocClass) {
+        stateNode = superClass.typeArguments?.arguments[1];
+      }
+      if (stateNode == null) {
+        return;
+      }
+      final stateType = stateNode.type as InterfaceType?;
+      if (stateType == null || _ignoredType.contains(stateType.element.name)) {
+        return;
+      }
+
+      if (stateType.element.name.endsWith('State') == false) {
+        reporter.atNode(stateNode, code);
+      }
+    });
+  }
+}

pubspec.lock

@@ -46,14 +46,6 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.12.0"
-  bloc:
-    dependency: transitive
-    description:
-      name: bloc
-      sha256: "106842ad6569f0b60297619e9e0b1885c2fb9bf84812935490e6c5275777804e"
-      url: "https://pub.dev"
-    source: hosted
-    version: "8.1.4"
   boolean_selector:
     dependency: transitive
     description:
@@ -62,14 +54,6 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.1.2"
-  characters:
-    dependency: transitive
-    description:
-      name: characters
-      sha256: "04a925763edad70e8443c99234dc3328f442e811f1d8fd1a72f1c8ad0f69a605"
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.3.0"
   checked_yaml:
     dependency: transitive
     description:
@@ -182,19 +166,6 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.1.1"
-  flutter:
-    dependency: transitive
-    description: flutter
-    source: sdk
-    version: "0.0.0"
-  flutter_bloc:
-    dependency: "direct dev"
-    description:
-      name: flutter_bloc
-      sha256: b594505eac31a0518bdcb4b5b79573b8d9117b193cc80cc12e17d639b10aa27a
-      url: "https://pub.dev"
-    source: hosted
-    version: "8.1.6"
   freezed_annotation:
     dependency: transitive
     description:
@@ -291,14 +262,6 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.12.16+1"
-  material_color_utilities:
-    dependency: transitive
-    description:
-      name: material_color_utilities
-      sha256: f7142bb1154231d7ea5f96bc7bde4bda2a0945d2806bb11670e30b850d56bdec
-      url: "https://pub.dev"
-    source: hosted
-    version: "0.11.1"
   meta:
     dependency: transitive
     description:
@@ -315,14 +278,6 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.0.0"
-  nested:
-    dependency: transitive
-    description:
-      name: nested
-      sha256: "03bac4c528c64c95c722ec99280375a6f2fc708eec17c7b3f07253b626cd2a20"
-      url: "https://pub.dev"
-    source: hosted
-    version: "1.0.0"
   node_preamble:
     dependency: transitive
     description:
@@ -355,14 +310,6 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.5.1"
-  provider:
-    dependency: transitive
-    description:
-      name: provider
-      sha256: c8a055ee5ce3fd98d6fc872478b03823ffdb448699c6ebdbbc71d59b596fd48c
-      url: "https://pub.dev"
-    source: hosted
-    version: "6.1.2"
   pub_semver:
     dependency: transitive
     description:
@@ -419,11 +366,6 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.0.0"
-  sky_engine:
-    dependency: transitive
-    description: flutter
-    source: sdk
-    version: "0.0.99"
   source_map_stack_trace:
     dependency: transitive
     description:
@@ -536,14 +478,6 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "4.5.1"
-  vector_math:
-    dependency: transitive
-    description:
-      name: vector_math
-      sha256: "80b3257d1492ce4d091729e3a67a60407d227c27241d6927be0130c98e741803"
-      url: "https://pub.dev"
-    source: hosted
-    version: "2.1.4"
   very_good_analysis:
     dependency: "direct dev"
     description:
@@ -610,4 +544,3 @@ packages:
     version: "3.1.2"
 sdks:
   dart: ">=3.5.0 <4.0.0"
-  flutter: ">=1.16.0"