Make casts to int safe in dart2wasm. (#1416)

Co-authored-by: Kevin Moore <kevmoo@google.com>

_test_yaml/pubspec.yaml

@@ -11,7 +11,7 @@ dev_dependencies:
   build_verify: ^3.0.0
   checked_yaml: any
   dart_flutter_team_lints: ^2.0.0
-  json_annotation: ^4.7.0
+  json_annotation: ^4.8.1
   json_serializable: any
   path: ^1.8.2
   test: ^1.6.0

json_annotation/lib/src/json_serializable.dart

@@ -181,7 +181,7 @@ class JsonSerializable {
   ///   T Function(Object json) fromJsonT,
   /// ) {
   ///   return Response<T>()
-  ///     ..status = json['status'] as int
+  ///     ..status = (json['status'] as num).toInt()
   ///     ..value = fromJsonT(json['value']);
   /// }
   ///

json_serializable/CHANGELOG.md

@@ -1,8 +1,11 @@
 ## 6.8.0-wip
 
 - Add type arguments to `Map` literals used for `Record` serialization.
-- Added support for generating `ExampleJsonKeys`, exposing a secured way to access the json keys from the properties.
+- Added support for generating `ExampleJsonKeys`, exposing a secured way to 
+  access the json keys from the properties.
   ([#1164](https://github.com/google/json_serializable.dart/pull/1164))
+- Handle decoding an `int` value from a `double` literal. 
+  This now matches the behavior of `double` values being encoded as `int`.
 
 ## 6.7.1
 

json_serializable/lib/src/lambda_result.dart

@@ -20,9 +20,8 @@ class LambdaResult {
   final String lambda;
   final DartType? asContent;
 
-  String get _asContent => asContent == null ? '' : _asStatement(asContent!);
-
-  String get _fullExpression => '$expression$_asContent';
+  String get _fullExpression =>
+      asContent != null ? _cast(expression, asContent!) : expression;
 
   LambdaResult(this.expression, this.lambda, {this.asContent});
 
@@ -35,29 +34,35 @@ class LambdaResult {
           : '($closureArg) => $subField';
 }
 
-String _asStatement(DartType type) {
-  if (type.isLikeDynamic) {
-    return '';
+String _cast(String expression, DartType targetType) {
+  if (targetType.isLikeDynamic) {
+    return expression;
   }
 
-  final nullableSuffix = type.isNullableType ? '?' : '';
+  final nullableSuffix = targetType.isNullableType ? '?' : '';
 
-  if (coreIterableTypeChecker.isAssignableFromType(type)) {
-    final itemType = coreIterableGenericType(type);
+  if (coreIterableTypeChecker.isAssignableFromType(targetType)) {
+    final itemType = coreIterableGenericType(targetType);
     if (itemType.isLikeDynamic) {
-      return ' as List$nullableSuffix';
+      return '$expression as List$nullableSuffix';
     }
   }
 
-  if (coreMapTypeChecker.isAssignableFromType(type)) {
-    final args = type.typeArgumentsOf(coreMapTypeChecker)!;
+  if (coreMapTypeChecker.isAssignableFromType(targetType)) {
+    final args = targetType.typeArgumentsOf(coreMapTypeChecker)!;
     assert(args.length == 2);
 
     if (args.every((e) => e.isLikeDynamic)) {
-      return ' as Map$nullableSuffix';
+      return '$expression as Map$nullableSuffix';
     }
   }
 
-  final typeCode = typeToCode(type);
-  return ' as $typeCode';
+  final defaultDecodeValue = defaultDecodeLogic(targetType, expression);
+
+  if (defaultDecodeValue != null) {
+    return defaultDecodeValue;
+  }
+
+  final typeCode = typeToCode(targetType);
+  return '$expression as $typeCode';
 }

json_serializable/lib/src/type_helpers/duration_helper.dart

@@ -46,7 +46,7 @@ class DurationHelper extends TypeHelper {
 
     return DefaultContainer(
       expression,
-      'Duration(microseconds: $expression as int)',
+      'Duration(microseconds: ($expression as num).toInt())',
     );
   }
 }

json_serializable/lib/src/type_helpers/value_helper.dart

@@ -3,7 +3,6 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:analyzer/dart/element/type.dart';
-import 'package:source_helper/source_helper.dart';
 
 import '../shared_checkers.dart';
 import '../type_helper.dart';
@@ -35,22 +34,7 @@ class ValueHelper extends TypeHelper {
     String expression,
     TypeHelperContext context,
     bool defaultProvided,
-  ) {
-    if (targetType.isDartCoreObject && !targetType.isNullableType) {
-      final question = defaultProvided ? '?' : '';
-      return '$expression as Object$question';
-    } else if (targetType.isDartCoreObject || targetType is DynamicType) {
-      // just return it as-is. We'll hope it's safe.
-      return expression;
-    } else if (targetType.isDartCoreDouble) {
-      final targetTypeNullable = defaultProvided || targetType.isNullableType;
-      final question = targetTypeNullable ? '?' : '';
-      return '($expression as num$question)$question.toDouble()';
-    } else if (simpleJsonTypeChecker.isAssignableFromType(targetType)) {
-      final typeCode = typeToCode(targetType, forceNullable: defaultProvided);
-      return '$expression as $typeCode';
-    }
-
-    return null;
-  }
+  ) =>
+      defaultDecodeLogic(targetType, expression,
+          defaultProvided: defaultProvided);
 }

json_serializable/lib/src/utils.dart

@@ -9,6 +9,7 @@ import 'package:json_annotation/json_annotation.dart';
 import 'package:source_gen/source_gen.dart';
 import 'package:source_helper/source_helper.dart';
 
+import 'shared_checkers.dart';
 import 'type_helpers/config_types.dart';
 
 const _jsonKeyChecker = TypeChecker.fromRuntime(JsonKey);
@@ -220,6 +221,33 @@ String typeToCode(
   throw UnimplementedError('(${type.runtimeType}) $type');
 }
 
+String? defaultDecodeLogic(
+  DartType targetType,
+  String expression, {
+  bool defaultProvided = false,
+}) {
+  if (targetType.isDartCoreObject && !targetType.isNullableType) {
+    final question = defaultProvided ? '?' : '';
+    return '$expression as Object$question';
+  } else if (targetType.isDartCoreObject || targetType is DynamicType) {
+    // just return it as-is. We'll hope it's safe.
+    return expression;
+  } else if (targetType.isDartCoreDouble) {
+    final targetTypeNullable = defaultProvided || targetType.isNullableType;
+    final question = targetTypeNullable ? '?' : '';
+    return '($expression as num$question)$question.toDouble()';
+  } else if (targetType.isDartCoreInt) {
+    final targetTypeNullable = defaultProvided || targetType.isNullableType;
+    final question = targetTypeNullable ? '?' : '';
+    return '($expression as num$question)$question.toInt()';
+  } else if (simpleJsonTypeChecker.isAssignableFromType(targetType)) {
+    final typeCode = typeToCode(targetType, forceNullable: defaultProvided);
+    return '$expression as $typeCode';
+  }
+
+  return null;
+}
+
 extension ExecutableElementExtension on ExecutableElement {
   /// Returns the name of `this` qualified with the class name if it's a
   /// [MethodElement].