(riverpod_lint) Add new lint avoid_passing_build_context_to_providers (…

…#2928)

packages/riverpod_lint/README.md

@@ -44,6 +44,7 @@ Riverpod_lint adds various warnings with quick fixes and refactoring options, su
   - [provider\_dependencies (riverpod\_generator only)](#provider_dependencies-riverpod_generator-only)
   - [scoped\_providers\_should\_specify\_dependencies (generator only)](#scoped_providers_should_specify_dependencies-generator-only)
   - [avoid\_manual\_providers\_as\_generated\_provider\_dependency](#avoid_manual_providers_as_generated_provider_dependency)
+  - [avoid\_build\_context\_in\_providers (riverpod\_generator only)](#avoid_build_context_in_providers-riverpod_generator-only)
   - [provider\_parameters](#provider_parameters)
   - [avoid\_public\_notifier\_properties](#avoid_public_notifier_properties)
   - [unsupported\_provider\_value (riverpod\_generator only)](#unsupported_provider_value-riverpod_generator-only)
@@ -346,6 +347,39 @@ int example(ExampleRef ref) {
 }
 ```
 
+### avoid_build_context_in_providers (riverpod_generator only)
+
+Providers should not interact with `BuildContext`.
+
+**Good**:
+
+```dart
+@riverpod
+int fn(FnRef ref) => 0;
+
+@riverpod
+class MyNotifier extends _$MyNotifier {
+  int build() => 0;
+
+  void event() {}
+}
+```
+
+**Bad**:
+
+```dart
+// Providers should not receive a BuildContext as a parameter.
+int fn(FnRef ref, BuildContext context) => 0;
+
+@riverpod
+class MyNotifier extends _$MyNotifier {
+  int build() => 0;
+
+  // Notifiers should not have methods that receive a BuildContext as a parameter.
+  void event(BuildContext context) {}
+}
+```
+
 ### provider_parameters
 
 Providers' parameters should have a consistent ==. Meaning either the values should be cached, or the parameters should override ==.

packages/riverpod_lint/lib/riverpod_lint.dart

@@ -7,6 +7,7 @@ import 'src/assists/convert_to_widget_utils.dart';
 import 'src/assists/functional_to_class_based_provider.dart';
 import 'src/assists/wrap_with_consumer.dart';
 import 'src/assists/wrap_with_provider_scope.dart';
+import 'src/lints/avoid_build_context_in_providers.dart';
 import 'src/lints/avoid_manual_providers_as_generated_provider_dependency.dart';
 import 'src/lints/avoid_public_notifier_properties.dart';
 import 'src/lints/avoid_ref_inside_state_dispose.dart';
@@ -24,6 +25,7 @@ PluginBase createPlugin() => _RiverpodPlugin();
 class _RiverpodPlugin extends PluginBase {
   @override
   List<LintRule> getLintRules(CustomLintConfigs configs) => [
+        const AvoidBuildContextInProviders(),
         const AvoidPublicNotifierProperties(),
         const FunctionalRef(),
         const MissingProviderScope(),

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

@@ -0,0 +1,58 @@
+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 '../riverpod_custom_lint.dart';
+
+const TypeChecker buildContextType = TypeChecker.fromName(
+  'BuildContext',
+  packageName: 'flutter',
+);
+
+class AvoidBuildContextInProviders extends RiverpodLintRule {
+  const AvoidBuildContextInProviders() : super(code: _code);
+
+  static const _code = LintCode(
+    name: 'avoid_build_context_in_providers',
+    problemMessage:
+        'Passing BuildContext to providers indicates mixing UI with the business logic.',
+    errorSeverity: ErrorSeverity.WARNING,
+  );
+
+  @override
+  void run(
+    CustomLintResolver resolver,
+    ErrorReporter reporter,
+    CustomLintContext context,
+  ) {
+    riverpodRegistry(context).addFunctionalProviderDeclaration((declaration) {
+      final parameters = declaration.node.functionExpression.parameters!;
+      _emitWarningsForBuildContext(reporter, parameters);
+    });
+
+    riverpodRegistry(context).addClassBasedProviderDeclaration((declaration) {
+      final methods = declaration.node.members.whereType<MethodDeclaration>();
+
+      for (final method in methods) {
+        final parameters = method.parameters!;
+        _emitWarningsForBuildContext(reporter, parameters);
+      }
+    });
+  }
+
+  void _emitWarningsForBuildContext(
+    ErrorReporter reporter,
+    FormalParameterList parameters,
+  ) {
+    final buildContextParameters = parameters.parameters.where(
+      (e) =>
+          e.declaredElement?.type != null &&
+          buildContextType.isExactlyType(e.declaredElement!.type),
+    );
+
+    for (final contextParameter in buildContextParameters) {
+      reporter.reportErrorForNode(_code, contextParameter);
+    }
+  }
+}

packages/riverpod_lint_flutter_test/test/lints/avoid_build_context_in_providers.dart

@@ -0,0 +1,32 @@
+import 'package:flutter/widgets.dart';
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+
+part 'avoid_build_context_in_providers.g.dart';
+
+@riverpod
+int fn(
+  FnRef ref,
+  // expect_lint: avoid_build_context_in_providers
+  BuildContext context1, {
+  // expect_lint: avoid_build_context_in_providers
+  required BuildContext context2,
+}) =>
+    0;
+
+@riverpod
+class MyNotifier extends _$MyNotifier {
+  int build(
+    // expect_lint: avoid_build_context_in_providers
+    BuildContext context1, {
+    // expect_lint: avoid_build_context_in_providers
+    required BuildContext context2,
+  }) =>
+      0;
+
+  void event(
+    // expect_lint: avoid_build_context_in_providers
+    BuildContext context3, {
+    // expect_lint: avoid_build_context_in_providers
+    required BuildContext context4,
+  }) {}
+}