feat: add static code diagnostic prefer-using-list-view (#1088)

Co-authored-by: Dmitry Zhifarsky <[email protected]>

Author: lsaudon

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## Unreleased
 
 * fix: remove recursive traversal for [`ban-name`](https://dartcodemetrics.dev/docs/rules/common/ban-name) rule.
+* feat: add static code diagnostic [`prefer-using-list-view`](https://dartcodemetrics.dev/docs/rules/flutter/prefer-using-list-view).
 
 ## 5.1.0
 

lib/presets/flutter_all.yaml

@@ -13,3 +13,4 @@ dart_code_metrics:
     - prefer-correct-edge-insets-constructor
     - prefer-extracting-callbacks
     - prefer-single-widget-per-file
+    - prefer-using-list-view

lib/src/analyzers/lint_analyzer/rules/rules_factory.dart

@@ -65,6 +65,7 @@ import 'rules_list/prefer_on_push_cd_strategy/prefer_on_push_cd_strategy_rule.da
 import 'rules_list/prefer_single_widget_per_file/prefer_single_widget_per_file_rule.dart';
 import 'rules_list/prefer_static_class/prefer_static_class_rule.dart';
 import 'rules_list/prefer_trailing_comma/prefer_trailing_comma_rule.dart';
+import 'rules_list/prefer_using_list_view/prefer_using_list_view_rule.dart';
 import 'rules_list/provide_correct_intl_args/provide_correct_intl_args_rule.dart';
 import 'rules_list/tag_name/tag_name_rule.dart';
 
@@ -144,6 +145,7 @@ final _implementedRules = <String, Rule Function(Map<String, Object>)>{
   PreferSingleWidgetPerFileRule.ruleId: PreferSingleWidgetPerFileRule.new,
   PreferStaticClassRule.ruleId: PreferStaticClassRule.new,
   PreferTrailingCommaRule.ruleId: PreferTrailingCommaRule.new,
+  PreferUsingListViewRule.ruleId: PreferUsingListViewRule.new,
   ProvideCorrectIntlArgsRule.ruleId: ProvideCorrectIntlArgsRule.new,
   TagNameRule.ruleId: TagNameRule.new,
 };

lib/src/analyzers/lint_analyzer/rules/rules_list/prefer_using_list_view/prefer_using_list_view_rule.dart

@@ -0,0 +1,49 @@
+// ignore_for_file: public_member_api_docs
+
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/visitor.dart';
+import 'package:collection/collection.dart';
+
+import '../../../../../utils/flutter_types_utils.dart';
+import '../../../../../utils/node_utils.dart';
+import '../../../lint_utils.dart';
+import '../../../models/internal_resolved_unit_result.dart';
+import '../../../models/issue.dart';
+import '../../../models/severity.dart';
+import '../../models/flutter_rule.dart';
+import '../../rule_utils.dart';
+
+part 'visitor.dart';
+
+class PreferUsingListViewRule extends FlutterRule {
+  static const String ruleId = 'prefer-using-list-view';
+
+  static const _warning =
+      'Preferred to use ListView instead of the combo SingleChildScrollView and Column.';
+
+  PreferUsingListViewRule([Map<String, Object> config = const {}])
+      : super(
+          id: ruleId,
+          severity: readSeverity(config, Severity.performance),
+          excludes: readExcludes(config),
+          includes: readIncludes(config),
+        );
+
+  @override
+  Iterable<Issue> check(InternalResolvedUnitResult source) {
+    final visitor = _Visitor();
+
+    source.unit.visitChildren(visitor);
+
+    return visitor.expressions
+        .map((expression) => createIssue(
+              rule: this,
+              location: nodeLocation(
+                node: expression,
+                source: source,
+              ),
+              message: _warning,
+            ))
+        .toList(growable: false);
+  }
+}

lib/src/analyzers/lint_analyzer/rules/rules_list/prefer_using_list_view/visitor.dart

@@ -0,0 +1,38 @@
+part of 'prefer_using_list_view_rule.dart';
+
+class _Visitor extends RecursiveAstVisitor<void> {
+  final _expressions = <Expression>[];
+
+  Iterable<Expression> get expressions => _expressions;
+
+  @override
+  void visitInstanceCreationExpression(InstanceCreationExpression node) {
+    super.visitInstanceCreationExpression(node);
+
+    if (isSingleChildScrollViewWidget(node.staticType) &&
+        _hasColumnChild(node)) {
+      _expressions.add(node);
+    }
+  }
+
+  bool _hasColumnChild(InstanceCreationExpression node) {
+    final child = node.argumentList.arguments.firstWhereOrNull(
+      (arg) => arg is NamedExpression && arg.name.label.name == 'child',
+    );
+
+    if (child != null && child is NamedExpression) {
+      final expression = child.expression;
+
+      if (expression is InstanceCreationExpression &&
+          isColumnWidget(expression.staticType)) {
+        final notChildren = expression.argumentList.arguments.firstWhereOrNull(
+          (arg) => arg is NamedExpression && arg.name.label.name != 'children',
+        );
+
+        return notChildren == null;
+      }
+    }
+
+    return false;
+  }
+}

lib/src/utils/flutter_types_utils.dart

@@ -30,6 +30,9 @@ bool isSubclassOfListenable(DartType? type) =>
 bool isListViewWidget(DartType? type) =>
     type?.getDisplayString(withNullability: false) == 'ListView';
 
+bool isSingleChildScrollViewWidget(DartType? type) =>
+    type?.getDisplayString(withNullability: false) == 'SingleChildScrollView';
+
 bool isColumnWidget(DartType? type) =>
     type?.getDisplayString(withNullability: false) == 'Column';
 

test/src/analyzers/lint_analyzer/rules/rules_factory_test.dart

@@ -48,6 +48,7 @@ void main() {
         'format-comment': <String, Object>{},
         'prefer-immediate-return': <String, Object>{},
         'tag-name': <String, Object>{},
+        'prefer-using-list-view': <String, Object>{},
       }).map((rule) => rule.id),
       equals([
         'always-remove-listener',
@@ -89,6 +90,7 @@ void main() {
         'prefer-on-push-cd-strategy',
         'prefer-single-widget-per-file',
         'prefer-trailing-comma',
+        'prefer-using-list-view',
         'provide-correct-intl-args',
         'tag-name',
       ]),

test/src/analyzers/lint_analyzer/rules/rules_list/prefer_using_list_view/examples/example.dart

@@ -0,0 +1,67 @@
+import 'package:flutter/material.dart';
+
+void main() {
+  runApp(MyApp());
+}
+
+class MyApp extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    // LINT
+    return SingleChildScrollView(
+      child: Column(
+        children: [
+          Text('Wow lint rule'),
+          Text('Wow another lint rule'),
+        ],
+      ),
+    );
+  }
+}
+
+class MyApp extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return SingleChildScrollView(
+      child: Column(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          Text('Wow lint rule'),
+          Text('Wow another lint rule'),
+        ],
+      ),
+    );
+  }
+}
+
+class MyApp extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return SingleChildScrollView(
+      child: Column(
+        mainAxisAlignment: MainAxisAlignment.start,
+        children: [
+          Text('Wow lint rule'),
+          Text('Wow another lint rule'),
+        ],
+      ),
+    );
+  }
+}
+
+class MyApp extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      home: Scaffold(
+        body: SingleChildScrollView(
+          child: Text(),
+        ),
+      ),
+    );
+  }
+}
+
+class SingleChildScrollView {}
+
+class Column {}

test/src/analyzers/lint_analyzer/rules/rules_list/prefer_using_list_view/prefer_using_list_view_rule_test.dart

@@ -0,0 +1,39 @@
+import 'package:dart_code_metrics/src/analyzers/lint_analyzer/models/severity.dart';
+import 'package:dart_code_metrics/src/analyzers/lint_analyzer/rules/rules_list/prefer_using_list_view/prefer_using_list_view_rule.dart';
+import 'package:test/test.dart';
+
+import '../../../../../helpers/rule_test_helper.dart';
+
+const _examplePath = 'prefer_using_list_view/examples/example.dart';
+
+void main() {
+  group(
+    'PreferUsingListViewRule',
+    () {
+      test('initialization', () async {
+        final unit = await RuleTestHelper.resolveFromFile(_examplePath);
+        final issues = PreferUsingListViewRule().check(unit);
+
+        RuleTestHelper.verifyInitialization(
+          issues: issues,
+          ruleId: 'prefer-using-list-view',
+          severity: Severity.performance,
+        );
+      });
+
+      test('reports about found issues', () async {
+        final unit = await RuleTestHelper.resolveFromFile(_examplePath);
+        final issues = PreferUsingListViewRule().check(unit);
+
+        RuleTestHelper.verifyIssues(
+          issues: issues,
+          startLines: [11],
+          startColumns: [12],
+          messages: [
+            'Preferred to use ListView instead of the combo SingleChildScrollView and Column.',
+          ],
+        );
+      });
+    },
+  );
+}

website/docs/rules/flutter/prefer-using-list-view.mdx

@@ -0,0 +1,35 @@
+import RuleDetails from '@site/src/components/RuleDetails';
+
+<RuleDetails version="5.2.0" severity="performance" />
+
+Warns when a `Column` widget with only `children` parameter is wrapped in a `SingleChildScrollView` widget.
+
+Additional resources:
+
+- <https://stackoverflow.com/a/62147092>
+
+### Example {#example}
+
+**❌ Bad:**
+
+```dart
+SingleChildScrollView(
+  child: Column(
+    children: [
+      Text('Wow lint rule'),
+      Text('Wow another lint rule'),
+    ],
+  ),
+),
+```
+
+**✅ Good:**
+
+```dart
+ListView(
+  children: [
+    Text('Wow lint rule'),
+    Text('Wow another lint rule'),
+  ],
+),
+```

website/docs/rules/index.mdx

@@ -648,6 +648,15 @@ Rules are grouped by category to help you understand their purpose. Each rule ha
   Warns when a file contains more than a single widget.
 </RuleEntry>
 
+<RuleEntry
+  name="prefer-using-list-view"
+  type="flutter"
+  severity="performance"
+  version="5.2.0"
+>
+  Warns when a <code>Column</code> widget with only <code>children</code> parameter is wrapped in a <code>SingleChildScrollView</code> widget.
+</RuleEntry>
+
 ## Intl specific {#intl-specific}
 
 <RuleEntry