Issue 190. Implement use nearest context rule

CHANGELOG.md

@@ -14,6 +14,7 @@
   - Update min Dart SDK constraint to 3.5.0
   - Update `analyzer` dependency to 7.1.0
   - Update `custom_lint_builder` dependency to 0.7.1
+- Added `use_nearest_context` rule
 
 ## 0.2.3
 

lib/solid_lints.dart

@@ -28,6 +28,7 @@ import 'package:solid_lints/src/lints/prefer_first/prefer_first_rule.dart';
 import 'package:solid_lints/src/lints/prefer_last/prefer_last_rule.dart';
 import 'package:solid_lints/src/lints/prefer_match_file_name/prefer_match_file_name_rule.dart';
 import 'package:solid_lints/src/lints/proper_super_calls/proper_super_calls_rule.dart';
+import 'package:solid_lints/src/lints/use_nearest_context/use_nearest_context_rule.dart';
 import 'package:solid_lints/src/models/solid_lint_rule.dart';
 
 /// Creates a plugin for our custom linter
@@ -65,6 +66,7 @@ class _SolidLints extends PluginBase {
       AvoidDebugPrintInReleaseRule.createRule(configs),
       PreferEarlyReturnRule.createRule(configs),
       AvoidFinalWithGetterRule.createRule(configs),
+      UseNearestContextRule.createRule(configs),
     ];
 
     // Return only enabled rules

lib/src/lints/use_nearest_context/fixes/use_nearest_context_fix.dart

@@ -0,0 +1,65 @@
+part of '../use_nearest_context_rule.dart';
+
+/// A Quick fix for `use_nearest_context` rule
+/// Suggests to renaming the nearest BuildContext variable
+/// to the one that is being used
+class _UseNearestContextFix extends DartFix {
+  static const _replaceComment = "Rename the BuildContext variable";
+
+  @override
+  void run(
+    CustomLintResolver resolver,
+    ChangeReporter reporter,
+    CustomLintContext context,
+    AnalysisError analysisError,
+    List<AnalysisError> others,
+  ) {
+    context.registry.addFunctionDeclaration((node) {
+      final statementInfo = analysisError.data as StatementInfo?;
+      if (statementInfo == null) return;
+      final parameterName = statementInfo.parameter.name;
+      if (parameterName == null) return;
+      if (node.sourceRange.intersects(parameterName.sourceRange)) {
+        _addReplacement(
+          reporter,
+          parameterName,
+          statementInfo.name,
+        );
+      }
+    });
+  }
+
+  void _addReplacement(
+    ChangeReporter reporter,
+    Token? token,
+    String correction,
+  ) {
+    if (token == null) return;
+    final changeBuilder = reporter.createChangeBuilder(
+      message: _replaceComment,
+      priority: 1,
+    );
+
+    changeBuilder.addDartFileEdit((builder) {
+      builder.addSimpleReplacement(
+        token.sourceRange,
+        correction,
+      );
+    });
+  }
+}
+
+/// Data class contains info required for fix
+class StatementInfo {
+  /// Creates instance of an [StatementInfo]
+  const StatementInfo({
+    required this.name,
+    required this.parameter,
+  });
+
+  /// Variable name
+  final String name;
+
+  /// BuildContext parament
+  final SimpleFormalParameter parameter;
+}

lib/src/lints/use_nearest_context/use_nearest_context_rule.dart

@@ -0,0 +1,124 @@
+// ignore_for_file: avoid_print, lines_longer_than_80_chars
+
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/token.dart';
+import 'package:analyzer/error/error.dart';
+import 'package:analyzer/error/listener.dart';
+import 'package:custom_lint_builder/custom_lint_builder.dart';
+import 'package:solid_lints/src/models/rule_config.dart';
+import 'package:solid_lints/src/models/solid_lint_rule.dart';
+import 'package:solid_lints/src/utils/types_utils.dart';
+
+part 'fixes/use_nearest_context_fix.dart';
+
+/// A rule which checks that we use BuildContext from the nearest available
+/// scope.
+///
+/// ### Example:
+/// #### BAD:
+/// ```dart
+/// class SomeWidget extends StatefulWidget {
+/// ...
+/// }
+///
+/// class _SomeWidgetState extends State<SomeWidget> {
+///   ...
+///   void _showDialog() {
+///     showModalBottomSheet(
+///       context: context,
+///       builder: (BuildContext _) {
+///         final someProvider = context.watch<SomeProvider>(); // LINT, BuildContext is used not from the nearest available scope
+///
+///         return const SizedBox.shrink();
+///       },
+///     );
+///   }
+/// }
+/// ```
+/// #### GOOD:
+/// ```dart
+/// class SomeWidget extends StatefulWidget {
+/// ...
+/// }
+///
+/// class _SomeWidgetState extends State<SomeWidget> {
+///   ...
+///   void _showDialog() {
+///     showModalBottomSheet(
+///       context: context,
+///       builder: (BuildContext context)
+///         final someProvider = context.watch<SomeProvider>(); // OK
+///
+///         return const SizedBox.shrink();
+///       },
+///     );
+///   }
+/// }
+/// ```
+///
+class UseNearestContextRule extends SolidLintRule {
+  /// This lint rule represents the error if BuildContext is used not from the
+  /// nearest available scope
+  static const lintName = 'use_nearest_context';
+
+  UseNearestContextRule._(super.rule);
+
+  /// Creates a new instance of [UseNearestContextRule]
+  /// based on the lint configuration.
+  factory UseNearestContextRule.createRule(CustomLintConfigs configs) {
+    final rule = RuleConfig(
+      configs: configs,
+      name: lintName,
+      problemMessage: (value) =>
+          'BuildContext is used not from the nearest available scope. '
+          'Consider renaming the nearest BuildContext parameter.',
+    );
+
+    return UseNearestContextRule._(rule);
+  }
+
+  @override
+  void run(
+    CustomLintResolver resolver,
+    ErrorReporter reporter,
+    CustomLintContext context,
+  ) {
+    context.registry.addSimpleIdentifier((node) {
+      if (!isBuildContext(node.staticType)) return;
+
+      final closestBuildContext = _findClosestBuildContext(node);
+      if (closestBuildContext == null) return;
+      if (closestBuildContext.name?.lexeme != node.name) {
+        reporter.atNode(
+          node,
+          code,
+          data: StatementInfo(
+            name: node.name,
+            parameter: closestBuildContext,
+          ),
+        );
+      }
+    });
+  }
+
+  SimpleFormalParameter? _findClosestBuildContext(SimpleIdentifier node) {
+    AstNode? current = node.parent;
+
+    while (current != null) {
+      if (current is FunctionExpression) {
+        final functionParams = current.parameters?.parameters ?? [];
+        for (final param in functionParams) {
+          if (param is SimpleFormalParameter &&
+              isBuildContext(param.declaredElement?.type)) {
+            return param;
+          }
+        }
+      }
+      current = current.parent;
+    }
+    return null;
+  }
+
+  @override
+  List<Fix> getFixes() => [_UseNearestContextFix()];
+}

lint_test/analysis_options.yaml

@@ -81,3 +81,4 @@ custom_lint:
     - prefer_match_file_name
     - proper_super_calls
     - avoid_final_with_getter
+    - use_nearest_context

lint_test/use_nearest_context_test.dart

@@ -0,0 +1,60 @@
+// ignore_for_file: avoid_unused_parameters, unused_local_variable
+import 'package:flutter/material.dart';
+
+/// Check the `use_nearest_context` rule
+void showDialog(BuildContext context) {
+  final outerContext = context;
+
+  showModalBottomSheet(
+    context: context,
+    builder: (BuildContext _) {
+      /// expect_lint: use_nearest_context
+      return SizedBox.fromSize(size: outerContext.size);
+    },
+  );
+
+  showModalBottomSheet(
+    context: context,
+    builder: (BuildContext _) {
+      /// expect_lint: use_nearest_context
+      return SizedBox.fromSize(size: context.size);
+    },
+  );
+
+  final fun = ({required BuildContext context}) {
+    /// expect_lint: use_nearest_context
+    outerContext.mounted;
+  };
+
+  showModalBottomSheet(
+    context: context,
+    builder: (_) {
+      /// expect_lint: use_nearest_context
+      return SizedBox.fromSize(size: context.size);
+    },
+  );
+
+  showModalBottomSheet(
+    context: context,
+    builder: (BuildContext innerContext) {
+      /// expect_lint: use_nearest_context
+      return SizedBox.fromSize(size: context.size);
+    },
+  );
+
+  showModalBottomSheet(
+      context: context,
+      builder: (BuildContext innerContext) {
+        ///Allowed
+        return SizedBox.fromSize(size: innerContext.size);
+      });
+
+  showModalBottomSheet(
+    ///Allowed
+    context: context,
+    builder: (BuildContext context) {
+      ///Allowed
+      return SizedBox.fromSize(size: context.size);
+    },
+  );
+}