fix(#2): Denying the definition of hooks within a class.

Author: nikaera

packages/flutter_hooks_lint/lib/flutter_hooks_lint.dart

@@ -5,6 +5,7 @@ library;
 
 import 'package:custom_lint_builder/custom_lint_builder.dart';
 import 'package:flutter_hooks_lint/src/rules/hooks_avoid_nesting_rule.dart';
+import 'package:flutter_hooks_lint/src/rules/hooks_avoid_within_class_rule.dart';
 import 'package:flutter_hooks_lint/src/rules/hooks_callback_consideration_rule.dart';
 import 'package:flutter_hooks_lint/src/rules/hooks_extends_rule.dart';
 import 'package:flutter_hooks_lint/src/rules/hooks_memoized_consideration_rule.dart';
@@ -20,6 +21,7 @@ class _FlutterHooksLinter extends PluginBase {
       const HooksExtendsRule(),
       const HooksUnuseWidgetRule(),
       const HooksAvoidNestingRule(),
+      const HooksAvoidWithinClassRule(),
       const HooksNameConventionRule(),
       const HooksMemoizedConsiderationRule(),
       const HooksCallbackConsiderationRule(),

packages/flutter_hooks_lint/lib/src/rules/hooks_avoid_within_class_rule.dart

@@ -0,0 +1,51 @@
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/visitor.dart';
+import 'package:analyzer/error/error.dart';
+import 'package:analyzer/error/listener.dart';
+import 'package:custom_lint_builder/custom_lint_builder.dart';
+import 'package:flutter_hooks_lint/src/visitors/hooks_method_visitor.dart';
+
+class HooksAvoidWithinClassRule extends DartLintRule {
+  const HooksAvoidWithinClassRule() : super(code: _code);
+
+  static const _code = LintCode(
+    name: 'hooks_avoid_within_class',
+    problemMessage: 'Hooks must not be defined within the class',
+    errorSeverity: ErrorSeverity.WARNING,
+  );
+
+  @override
+  void run(
+    CustomLintResolver resolver,
+    ErrorReporter reporter,
+    CustomLintContext context,
+  ) {
+    context.registry.addClassDeclaration((declaration) {
+      final collector = _MethodCollector();
+      declaration.visitChildren(collector);
+
+      for (final methodDeclaration in collector.methods) {
+        // TODO(nikaera): should only detect when the build function name is inherited from the Widget class.
+        if ('build' == methodDeclaration.name.lexeme) continue;
+
+        methodDeclaration.visitChildren(
+          HooksMethodVisitor(
+            onVisitMethodInvocation: (node) {
+              reporter.reportErrorForNode(code, methodDeclaration);
+            },
+          ),
+        );
+      }
+    });
+  }
+}
+
+class _MethodCollector extends GeneralizingAstVisitor<void> {
+  final List<MethodDeclaration> methods = [];
+
+  @override
+  void visitMethodDeclaration(MethodDeclaration node) {
+    methods.add(node);
+    super.visitMethodDeclaration(node);
+  }
+}

packages/flutter_hooks_lint/lib/src/rules/hooks_name_convention_rule.dart

@@ -1,8 +1,12 @@
+import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/error/listener.dart';
 import 'package:custom_lint_builder/custom_lint_builder.dart';
+import 'package:flutter_hooks_lint/src/helpers/hooks_helper.dart';
 import 'package:flutter_hooks_lint/src/visitors/hooks_method_visitor.dart';
 
+final _regexp = RegExp('^use[A-Z]{1}');
+
 class HooksNameConventionRule extends DartLintRule {
   const HooksNameConventionRule() : super(code: _code);
 
@@ -19,13 +23,24 @@ class HooksNameConventionRule extends DartLintRule {
     ErrorReporter reporter,
     CustomLintContext context,
   ) {
-    context.registry.addMethodDeclaration((classNode) {
-      final regexp = RegExp('^use[A-Z]{1}');
+    context.registry.addMethodDeclaration((node) {
+      final classDeclaration = node.thisOrAncestorOfType<ClassDeclaration>();
+      final extendsClause = classDeclaration?.extendsClause;
+      if (extendsClause == null) {
+        return;
+      }
+      final extendsElement = extendsClause.superclass.element;
+      if (extendsElement == null) {
+        return;
+      }
+      if (!HooksHelper.isHooksElement(extendsElement)) {
+        return;
+      }
 
-      classNode.visitChildren(
+      node.visitChildren(
         HooksMethodVisitor(
           onVisitMethodInvocation: (node) {
-            if (!regexp.hasMatch(node.methodName.name)) {
+            if (!_regexp.hasMatch(node.methodName.name)) {
               reporter.reportErrorForNode(code, node);
             }
           },

packages/flutter_hooks_lint/lib/src/visitors/hooks_method_visitor.dart

@@ -2,56 +2,69 @@ import 'package:analyzer/dart/analysis/analysis_context_collection.dart';
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
-import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/file_system/physical_file_system.dart';
 import 'package:flutter_hooks_lint/src/helpers/hooks_helper.dart';
 
+final _regexp = RegExp('^use[A-Z]{1}');
+
 class HooksMethodVisitor extends RecursiveAstVisitor<void> {
   const HooksMethodVisitor({
     required this.onVisitMethodInvocation,
+    this.caller,
   });
+
   final void Function(MethodInvocation node) onVisitMethodInvocation;
+  final MethodInvocation? caller;
 
+  /*
+    TODO(nikaera): I would like to recursively verify whether a function accurately utilizes
+the hooks package using getResolvedUnit. However, the execution time becomes
+excessively long. Hence, I am simplifying the process by examining if the
+function, which I aim to explore using getParsedUnit, employs the hooks
+package from the AST of a single file where the function is defined.
+  */
   @override
   void visitMethodInvocation(MethodInvocation node) {
     final element = node.methodName.staticElement;
     if (element == null) {
-      return;
+      if (caller != null && _regexp.hasMatch(node.methodName.name)) {
+        onVisitMethodInvocation(caller!);
+      }
+      return super.visitMethodInvocation(node);
     }
 
     final methodName = node.methodName.name;
+
     final isDartCoreMethod = element.library?.isDartCore ?? false;
     final isInSdkMethod = element.library?.isInSdk ?? false;
 
     if (HooksHelper.isHooksElement(element)) {
       onVisitMethodInvocation(node);
     } else if (!isDartCoreMethod && !isInSdkMethod) {
-      try {
-        final filePath = element.librarySource?.fullName;
-        if (filePath != null) {
-          final collection = AnalysisContextCollection(
-            includedPaths: [filePath],
-            resourceProvider: PhysicalResourceProvider.INSTANCE,
-          );
+      final filePath = element.librarySource?.fullName;
+      if (filePath != null) {
+        final collection = AnalysisContextCollection(
+          includedPaths: [filePath],
+          resourceProvider: PhysicalResourceProvider.INSTANCE,
+        );
 
-          final context = collection.contextFor(filePath);
-          final result = context.currentSession.getParsedUnit(filePath);
+        final context = collection.contextFor(filePath);
+        final result = context.currentSession.getParsedUnit(filePath);
+        result as ParsedUnitResult;
 
-          if (result is ParsedUnitResult) {
-            final AstNode rootNode = result.unit;
-            rootNode.visitChildren(
-              _SpecificFunctionDeclarationVisitor(
-                functionName: methodName,
-                onVisitFunctionDeclaration: (node) {
-                  node.visitChildren(this);
-                },
-              ),
-            );
-          }
-          onVisitMethodInvocation(node);
-        }
-      } catch (e) {
-        print('$methodName: $e');
+        result.unit.visitChildren(
+          _SpecificFunctionDeclarationVisitor(
+            functionName: methodName,
+            onVisitFunctionDeclaration: (childNode) {
+              childNode.visitChildren(
+                HooksMethodVisitor(
+                  caller: caller ?? node,
+                  onVisitMethodInvocation: onVisitMethodInvocation,
+                ),
+              );
+            },
+          ),
+        );
       }
     }
 

packages/flutter_hooks_lint_flutter_test/test/golden.dart

@@ -9,7 +9,7 @@ import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/dart/analysis/utilities.dart';
 
 @Deprecated('Do not commit')
-var goldenWrite = false;
+final goldenWrite = false;
 
 File writeToTemporaryFile(String content) {
   final tempDir = Directory.systemTemp.createTempSync();
@@ -31,7 +31,6 @@ void testGolden(
 }) {
   test(description, () async {
     final file = File(sourcePath).absolute;
-
     final result = await resolveFile2(path: file.path);
     result as ResolvedUnitResult;
 

packages/flutter_hooks_lint_flutter_test/test/hooks_unuse_widget/custom_hooks.dart renamed to packages/flutter_hooks_lint_flutter_test/test/hooks_avoid_within_class/hooks_avoid_within_class.dart

@@ -0,0 +1,15 @@
+import 'dart:io';
+
+import 'package:flutter_hooks_lint/src/rules/hooks_avoid_within_class_rule.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test('Check nested using of flutter_hooks methods', () async {
+    final file =
+        File('test/hooks_avoid_within_class/hooks_avoid_within_class.dart')
+            .absolute;
+    final errors = await HooksAvoidWithinClassRule().testAnalyzeAndRun(file);
+
+    expect(errors, hasLength(1));
+  }, retry: 0);
+}

packages/flutter_hooks_lint_flutter_test/test/hooks_avoid_within_class/hooks_avoid_within_class_test.dart

@@ -17,3 +17,13 @@ class RequiresConsumerHookWidget extends ConsumerWidget {
     return Text(state.value.toString());
   }
 }
+
+final _textProvider = Provider((ref) => "");
+
+class RiverpodWidget extends ConsumerWidget {
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final text = ref.watch(_textProvider);
+    return Text(text);
+  }
+}

packages/flutter_hooks_lint_flutter_test/test/hooks_extends/hooks_extends.dart

@@ -1,7 +1,7 @@
 import "package:flutter/material.dart";
 import "package:flutter_hooks/flutter_hooks.dart";
 
-import "custom_hooks.dart";
+import "src/custom_hooks.dart";
 
 class CorrectMethodWidget extends HookWidget {
   @override

packages/flutter_hooks_lint_flutter_test/test/hooks_name_convention/hooks_name_convention.dart

@@ -1,7 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_hooks/flutter_hooks.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
-import 'custom_hooks.dart';
+import 'src/custom_hooks.dart';
 
 class UnuseHookWidget extends HookWidget {
   @override

packages/flutter_hooks_lint_flutter_test/test/hooks_name_convention/custom_hooks.dart renamed to packages/flutter_hooks_lint_flutter_test/test/hooks_name_convention/src/custom_hooks.dart

@@ -2,7 +2,7 @@ Message: `Convert to StatelessWidget`
 Priority: 30
 Diff for file `test/hooks_unuse_widget/hooks_unuse_widget.dart:6`:
 ```
-import 'custom_hooks.dart';
+import 'src/custom_hooks.dart';
 
 - class UnuseHookWidget extends HookWidget {
 + class UnuseHookWidget extends StatelessWidget {

packages/flutter_hooks_lint_flutter_test/test/hooks_unuse_widget/hooks_unuse_widget.dart

@@ -0,0 +1,13 @@
+import 'package:flutter_hooks/flutter_hooks.dart';
+
+void useEffectOnce(Dispose? Function() effect) {
+  useEffect(effect, const []);
+}
+
+class TestHelper {
+  const TestHelper._();
+
+  static void useEffectOnce(Dispose? Function() effect) {
+    useEffect(effect, const []);
+  }
+}