| // Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| import 'package:analyzer/dart/analysis/features.dart'; |
| import 'package:analyzer/dart/ast/ast.dart'; |
| import 'package:analyzer/dart/ast/token.dart'; |
| import 'package:analyzer/dart/ast/visitor.dart'; |
| |
| import '../analyzer.dart'; |
| import '../util/dart_type_utilities.dart'; |
| |
| const _desc = r'Specify `@required` on named parameters without defaults.'; |
| |
| const _details = r''' |
| |
| **DO** specify `@required` on named parameters without a default value on which |
| an `assert(param != null)` is done. |
| |
| **GOOD:** |
| ```dart |
| m1({@required a}) { |
| assert(a != null); |
| } |
| |
| m2({a: 1}) { |
| assert(a != null); |
| } |
| ``` |
| |
| **BAD:** |
| ```dart |
| m1({a}) { |
| assert(a != null); |
| } |
| ``` |
| |
| NOTE: Only asserts at the start of the bodies will be taken into account. |
| |
| '''; |
| |
| class AlwaysRequireNonNullNamedParameters extends LintRule |
| implements NodeLintRule { |
| AlwaysRequireNonNullNamedParameters() |
| : super( |
| name: 'always_require_non_null_named_parameters', |
| description: _desc, |
| details: _details, |
| group: Group.style); |
| |
| @override |
| void registerNodeProcessors( |
| NodeLintRegistry registry, LinterContext context) { |
| // In a Null Safety library, this lint is covered by other formal static |
| // analysis. |
| if (!context.isEnabled(Feature.non_nullable)) { |
| var visitor = _Visitor(this); |
| registry.addFormalParameterList(this, visitor); |
| } |
| } |
| } |
| |
| class _Visitor extends SimpleAstVisitor<void> { |
| final LintRule rule; |
| |
| _Visitor(this.rule); |
| |
| @override |
| void visitFormalParameterList(FormalParameterList node) { |
| List<DefaultFormalParameter> getParams() { |
| var params = <DefaultFormalParameter>[]; |
| for (var p in node.parameters) { |
| // Only named parameters |
| if (p.isNamed) { |
| var parameter = p as DefaultFormalParameter; |
| // Without a default value or marked required |
| if (parameter.defaultValue == null) { |
| var declaredElement = parameter.declaredElement; |
| if (declaredElement != null && !declaredElement.hasRequired) { |
| params.add(parameter); |
| } |
| } |
| } |
| } |
| return params; |
| } |
| |
| var parent = node.parent; |
| if (parent is FunctionExpression) { |
| _checkParams(getParams(), parent.body); |
| } else if (parent is ConstructorDeclaration) { |
| _checkInitializerList(getParams(), parent.initializers); |
| _checkParams(getParams(), parent.body); |
| } else if (parent is MethodDeclaration) { |
| _checkParams(getParams(), parent.body); |
| } |
| } |
| |
| void _checkAssert( |
| Expression assertExpression, List<DefaultFormalParameter> params) { |
| for (var param in params) { |
| var identifier = param.identifier; |
| if (identifier != null && |
| _hasAssertNotNull(assertExpression, identifier.name)) { |
| rule.reportLintForToken(identifier.beginToken); |
| params.remove(param); |
| return; |
| } |
| } |
| } |
| |
| void _checkInitializerList(List<DefaultFormalParameter> params, |
| NodeList<ConstructorInitializer> initializers) { |
| for (var initializer in initializers) { |
| if (initializer is AssertInitializer) { |
| _checkAssert(initializer.condition, params); |
| } |
| } |
| } |
| |
| void _checkParams(List<DefaultFormalParameter> params, FunctionBody? body) { |
| if (body is BlockFunctionBody) { |
| for (var statement in body.block.statements) { |
| if (statement is AssertStatement) { |
| _checkAssert(statement.condition, params); |
| } else { |
| // Bail on first non-assert. |
| return; |
| } |
| } |
| } |
| } |
| |
| bool _hasAssertNotNull(Expression node, String name) { |
| bool _hasSameName(Expression rawExpression) { |
| var expression = rawExpression.unParenthesized; |
| return expression is SimpleIdentifier && expression.name == name; |
| } |
| |
| var expression = node.unParenthesized; |
| if (expression is BinaryExpression) { |
| if (expression.operator.type == TokenType.AMPERSAND_AMPERSAND) { |
| return _hasAssertNotNull(expression.leftOperand, name) || |
| _hasAssertNotNull(expression.rightOperand, name); |
| } |
| if (expression.operator.type == TokenType.BANG_EQ) { |
| var operands = [expression.leftOperand, expression.rightOperand]; |
| return operands.any(DartTypeUtilities.isNullLiteral) && |
| operands.any(_hasSameName); |
| } |
| } |
| return false; |
| } |
| } |