chore(aws_common,3.0): Make AWSResult sealed

packages/auth/amplify_auth_cognito_dart/lib/src/model/auth_result.dart

@@ -3,13 +3,12 @@
 
 import 'package:amplify_core/amplify_core.dart';
 
-/// {@template amplify_auth_cognito.model.auth_result}
 /// The result of an Auth operation.
-/// {@endtemplate}
-class AuthResult<T> extends AWSResult<T, AuthException> {
-  /// Creates a failed Auth result.
-  const AuthResult.error(super.exception, [super.stackTrace]) : super.error();
-
-  /// Creates a successful Auth result.
-  const AuthResult.success(super.value) : super.success();
-}
+typedef AuthResult<T extends Object?> = AWSResult<T, AuthException>;
+
+/// A successful result to an Auth operation.
+typedef AuthSuccessResult<T extends Object?>
+    = AWSSuccessResult<T, AuthException>;
+
+/// A failed result to an Auth operation.
+typedef AuthErrorResult<T extends Object?> = AWSErrorResult<T, AuthException>;

packages/authenticator/amplify_authenticator/lib/src/services/amplify_auth_service.dart

@@ -203,22 +203,24 @@ class AmplifyAuthService
   @override
   Future<bool> isValidSession() async {
     return _withUserAgent(() async {
-      final res = await Amplify.Auth.fetchAuthSession() as CognitoAuthSession;
-      try {
+      final session =
+          await Amplify.Auth.fetchAuthSession() as CognitoAuthSession;
+      final CognitoAuthSession(:userPoolTokensResult) = session;
+      return switch (userPoolTokensResult) {
         // If tokens can be retrieved without an exception, return true.
-        res.userPoolTokensResult.value;
-        return true;
-      } on SignedOutException {
-        return false;
-      } on NetworkException {
-        // NetworkException indicates that access and/or id tokens have expired
-        // and cannot be refreshed due to a network error. In this case the user
-        // should be treated as authenticated to allow for offline use cases.
-        return true;
-      } on Exception {
-        // Any other exception should be thrown to be handled appropriately.
-        rethrow;
-      }
+        AuthSuccessResult _ => true,
+        AuthErrorResult(:final exception) => switch (exception) {
+            SignedOutException _ => false,
+
+            // NetworkException indicates that access and/or id tokens have expired
+            // and cannot be refreshed due to a network error. In this case the user
+            // should be treated as authenticated to allow for offline use cases.
+            NetworkException _ => true,
+
+            // Any other exception should be thrown to be handled appropriately.
+            _ => throw exception,
+          },
+      };
     });
   }
 

packages/aws_common/lib/src/result/aws_result.dart

@@ -10,69 +10,141 @@ import 'package:aws_common/aws_common.dart';
 /// throw an exception if an exception occurred. See [exception] for more
 /// details.
 /// {@endtemplate}
-class AWSResult<T, E extends Exception>
-    with AWSEquatable<AWSResult<T, E>>, AWSDebuggable {
+sealed class AWSResult<V extends Object?, E extends Exception>
+    with AWSDebuggable, AWSSerializable<Map<String, Object?>> {
   /// Creates a failed result.
-  const AWSResult.error(E this.exception, [this.stackTrace])
-      : type = AWSResultType.error,
-        _value = null;
+  const factory AWSResult.error(E exception, [StackTrace? stackTrace]) =
+      AWSErrorResult<V, E>;
 
   /// Creates a successful result.
-  const AWSResult.success(T value)
-      : _value = value,
-        type = AWSResultType.success,
-        exception = null,
-        stackTrace = null;
+  const factory AWSResult.success(V value) = AWSSuccessResult<V, E>;
 
-  /// The value of the result, or null.
-  final T? _value;
+  const AWSResult._();
 
   /// The exception that occurred while attempting to retrieve the value.
-  final E? exception;
+  E? get exception;
 
   /// The original stack trace of [exception], if provided.
-  final StackTrace? stackTrace;
+  StackTrace? get stackTrace;
 
   /// Indicates if the result was a success.
-  final AWSResultType type;
+  @Deprecated('Use pattern matching instead')
+  AWSResultType get type;
 
   /// The value of the result, if the result was successful.
   ///
   /// If an exception was thrown while retrieving the value, this will throw.
   /// See [exception] for more details.
-  T get value {
-    switch (type) {
-      case AWSResultType.success:
-        // value will be non-null since it is required in AWSResult.success.
-        return _value!;
-      case AWSResultType.error:
-        if (stackTrace != null) {
-          // TODO(dnys1): Chain, instead, so that the current stack trace can
-          /// provide context to the original
-        }
-        // ignore: only_throw_errors
-        throw exception!;
-    }
-  }
+  V get value;
 
   /// The value of the result, or null if there was an error retrieving it.
-  T? get valueOrNull {
-    switch (type) {
-      case AWSResultType.success:
-        // value will be non-null since it is required in AWSResult.success.
-        return _value!;
-      case AWSResultType.error:
-        return null;
+  V? get valueOrNull;
+}
+
+/// {@template aws_common.aws_success_result}
+/// A successful [AWSResult].
+///
+/// For successful results, [value] is guaranteed to not throw.
+/// {@endtemplate}
+final class AWSSuccessResult<V extends Object?, E extends Exception>
+    extends AWSResult<V, E> with AWSEquatable<AWSSuccessResult<V, E>> {
+  /// {@macro aws_common.aws_success_result}
+  const AWSSuccessResult(this.value) : super._();
+
+  @override
+  final V value;
+
+  @override
+  V get valueOrNull => value;
+
+  @override
+  AWSResultType get type => AWSResultType.success;
+
+  @override
+  E? get exception => null;
+
+  @override
+  StackTrace? get stackTrace => null;
+
+  @override
+  List<Object?> get props => [value];
+
+  @override
+  String get runtimeTypeName {
+    final typeName = StringBuffer('AWSSuccessResult<')
+      ..write(
+        switch (value) {
+          AWSDebuggable(:final runtimeTypeName) => runtimeTypeName,
+          _ => V,
+        },
+      )
+      ..write(', $E>');
+    return typeName.toString();
+  }
+
+  @override
+  Map<String, Object?> toJson() => {
+        'value': switch (value) {
+          final AWSSerializable serializable => serializable.toJson(),
+          _ => value.toString(),
+        },
+      };
+}
+
+/// {@template aws_common.aws_error_result}
+/// A failed [AWSResult].
+///
+/// For failed results, [value] will always throw and [exception] is guaranteed
+/// to not be `null`.
+/// {@endtemplate}
+final class AWSErrorResult<V extends Object?, E extends Exception>
+    extends AWSResult<V, E> with AWSEquatable<AWSErrorResult<V, E>> {
+  /// {@macro aws_common.aws_error_result}
+  const AWSErrorResult(this.exception, [this.stackTrace]) : super._();
+
+  @override
+  final E exception;
+
+  @override
+  final StackTrace? stackTrace;
+
+  @override
+  V get value {
+    if (stackTrace != null) {
+      // TODO(dnys1): Chain, instead, so that the current stack trace can
+      /// provide context to the original
     }
+    throw exception;
   }
 
   @override
-  List<Object?> get props => [
-        _value,
-        exception,
-        type,
-      ];
+  V? get valueOrNull => null;
+
+  @override
+  AWSResultType get type => AWSResultType.error;
+
+  @override
+  List<Object?> get props => [exception, stackTrace];
+
+  @override
+  String get runtimeTypeName {
+    final typeName = StringBuffer('AWSErrorResult<$V, ')
+      ..write(
+        switch (exception) {
+          AWSDebuggable(:final runtimeTypeName) => runtimeTypeName,
+          _ => E,
+        },
+      )
+      ..write('>');
+    return typeName.toString();
+  }
 
   @override
-  String get runtimeTypeName => 'AWSResult';
+  Map<String, Object?> toJson() => {
+        'exception': switch (exception) {
+          final AWSSerializable serializable => serializable.toJson(),
+          _ => exception.toString(),
+        },
+        'stackTrace': stackTrace?.toString(),
+      };
 }

packages/aws_common/lib/src/util/debuggable.dart

@@ -16,13 +16,10 @@ mixin AWSDebuggable on Object {
   String get runtimeTypeName;
 
   @override
-  String toString() {
-    if (this is AWSSerializable) {
-      return '$runtimeTypeName ${prettyPrintJson((this as AWSSerializable).toJson())}';
-    }
-    if (this is AWSEquatable) {
-      return '$runtimeTypeName ${(this as AWSEquatable).props}';
-    }
-    return 'Instance of $runtimeTypeName';
-  }
+  String toString() => switch (this) {
+        AWSSerializable(:final toJson) =>
+          '$runtimeTypeName ${prettyPrintJson(toJson())}',
+        AWSEquatable(:final props) => '$runtimeTypeName $props',
+        _ => 'Instance of $runtimeTypeName',
+      };
 }