Adds notifier_build lint (#2839)

packages/riverpod_lint/CHANGELOG.md

@@ -1,3 +1,7 @@
+## Unreleased minor
+
+- Added `notifier_build`, a lint to catch when a Notifier has no `build` method (thansk to @LeonardoRosaa)
+
 ## 2.0.4 - 2023-09-04
 
 - `riverpod` upgraded to `2.4.0`

packages/riverpod_lint/README.md

@@ -50,6 +50,7 @@ Riverpod_lint adds various warnings with quick fixes and refactoring options, su
   - [functional\_ref (riverpod\_generator only)](#functional_ref-riverpod_generator-only)
   - [notifier\_extends (riverpod\_generator only)](#notifier_extends-riverpod_generator-only)
   - [avoid\_ref\_inside\_state\_dispose](#avoid_ref_inside_state_dispose)
+  - [missed\_build\_method (riverpod\_generator only)](#notifier_build-riverpod_generator-only)
 - [All assists](#all-assists)
   - [Wrap widgets with a `Consumer`](#wrap-widgets-with-a-consumer)
   - [Wrap widgets with a `ProviderScope`](#wrap-widgets-with-a-providerscope)
@@ -551,6 +552,29 @@ class _MyWidgetState extends ConsumerState<MyWidget> {
 }
 ```
 
+### notifier_build (riverpod_generator only)
+
+Classes annotated by `@riverpod` must have the `build` method.
+
+**Good**:
+
+```dart
+@riverpod
+class Example extends _$Example {
+  
+  @overried
+  int build() => 0;
+}
+```
+
+**Bad**:
+
+```dart
+// No "build" method found
+@riverpod
+class Example extends _$Example {}
+```
+
 ## All assists
 
 ### Wrap widgets with a `Consumer`

packages/riverpod_lint/lib/riverpod_lint.dart

@@ -12,6 +12,7 @@ import 'src/lints/avoid_public_notifier_properties.dart';
 import 'src/lints/avoid_ref_inside_state_dispose.dart';
 import 'src/lints/functional_ref.dart';
 import 'src/lints/missing_provider_scope.dart';
+import 'src/lints/notifier_build.dart';
 import 'src/lints/notifier_extends.dart';
 import 'src/lints/provider_dependencies.dart';
 import 'src/lints/provider_parameters.dart';
@@ -33,6 +34,7 @@ class _RiverpodPlugin extends PluginBase {
         const ScopedProvidersShouldSpecifyDependencies(),
         const UnsupportedProviderValue(),
         const AvoidRefInsideStateDispose(),
+        const NotifierBuild(),
 //         const AvoidDynamicProviders(),
 // //  "Avoid passing providers as parameter to objects"
 //         const AvoidExposingProviderRef(),

packages/riverpod_lint/lib/src/lints/notifier_build.dart

@@ -0,0 +1,90 @@
+import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/error/error.dart';
+import 'package:analyzer/error/listener.dart';
+import 'package:custom_lint_builder/custom_lint_builder.dart';
+import 'package:riverpod_analyzer_utils/riverpod_analyzer_utils.dart';
+
+import '../riverpod_custom_lint.dart';
+
+const _buildMethodName = 'build';
+
+class NotifierBuild extends RiverpodLintRule {
+  const NotifierBuild() : super(code: _code);
+
+  static const _code = LintCode(
+    name: 'notifier_build',
+    problemMessage:
+        'Classes annotated by `@riverpod` must have the `build` method',
+  );
+
+  @override
+  void run(
+    CustomLintResolver resolver,
+    ErrorReporter reporter,
+    CustomLintContext context,
+  ) {
+    context.registry.addClassDeclaration((node) {
+      final hasRiverpodAnnotation = node.metadata.where(
+        (element) {
+          final annotationElement = element.element;
+
+          if (annotationElement == null ||
+              annotationElement is! ExecutableElement) return false;
+
+          return riverpodType.isExactlyType(annotationElement.returnType);
+        },
+      ).isNotEmpty;
+
+      if (!hasRiverpodAnnotation) return;
+
+      final hasBuildMethod = node.members
+          .where((e) => e.declaredElement?.displayName == _buildMethodName)
+          .isNotEmpty;
+
+      if (hasBuildMethod) return;
+
+      reporter.reportErrorForToken(_code, node.name);
+    });
+  }
+
+  @override
+  List<RiverpodFix> getFixes() => [
+        AddBuildMethodFix(),
+      ];
+}
+
+class AddBuildMethodFix extends RiverpodFix {
+  @override
+  void run(
+    CustomLintResolver resolver,
+    ChangeReporter reporter,
+    CustomLintContext context,
+    AnalysisError analysisError,
+    List<AnalysisError> others,
+  ) {
+    context.registry.addClassDeclaration((node) {
+      if (!node.sourceRange.intersects(analysisError.sourceRange)) return;
+
+      final changeBuilder = reporter.createChangeBuilder(
+        message: 'Add build method',
+        priority: 80,
+      );
+
+      changeBuilder.addDartFileEdit((builder) {
+        final offset = node.leftBracket.offset + 1;
+
+        builder.addSimpleInsertion(
+          offset,
+          '''
+
+  @override
+  dynamic build() {
+    // TODO: implement build
+    throw UnimplementedError();
+  }
+''',
+        );
+      });
+    });
+  }
+}

packages/riverpod_lint_flutter_test/test/goldens/fixes/notifier_build.dart

@@ -0,0 +1,8 @@
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+
+/// Fake Provider
+typedef _$ExampleProvider1 = Object;
+
+@riverpod
+// expect_lint: notifier_build
+class ExampleProvider1 extends _$ExampleProvider1 {}

packages/riverpod_lint_flutter_test/test/goldens/fixes/notifier_build.json

@@ -0,0 +1 @@
+[]

packages/riverpod_lint_flutter_test/test/goldens/fixes/notifier_build_test.dart

@@ -0,0 +1,33 @@
+import 'dart:io';
+
+import 'package:collection/collection.dart';
+import 'package:riverpod_lint/src/lints/notifier_build.dart';
+import 'package:analyzer/dart/analysis/results.dart';
+import 'package:analyzer/dart/analysis/utilities.dart';
+
+import '../../golden.dart';
+
+void main() {
+  testGolden(
+    'Verify that @riverpod classes has the build method',
+    'goldens/fixes/notifier_build.json',
+    () async {
+      const lint = NotifierBuild();
+      final fix = lint.getFixes().single;
+      final file = File(
+        'test/goldens/fixes/notifier_build.dart',
+      ).absolute;
+
+      final result = await resolveFile2(path: file.path);
+      result as ResolvedUnitResult;
+
+      final errors = await lint.testRun(result);
+
+      final changes = await Future.wait([
+        for (final error in errors) fix.testRun(result, error, errors),
+      ]);
+
+      return changes.flattened;
+    },
+  );
+}

packages/riverpod_lint_flutter_test/test/goldens/lints/notifier_build.dart

@@ -0,0 +1,17 @@
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+
+/// Fake Provider
+typedef _$ExampleProvider1 = Object;
+
+/// Fake Provider
+typedef _$ExampleProvider = AutoDisposeNotifier<int>;
+
+@riverpod
+// expect_lint: notifier_build
+class ExampleProvider1 extends _$ExampleProvider1 {}
+
+@riverpod
+class ExampleProvider extends _$ExampleProvider {
+  @override
+  int build() => 0;
+}