Add stackTrace to AsyncSnapshot (#69507)

packages/flutter/lib/src/widgets/async.dart

@@ -75,10 +75,11 @@ abstract class StreamBuilderBase<T, S> extends StatefulWidget {
   /// is combined with the new data item in the fold computation.
   S afterData(S current, T data);
 
-  /// Returns an updated version of the [current] summary following an error.
+  /// Returns an updated version of the [current] summary following an error
+  /// with a stack trace.
   ///
   /// The default implementation returns [current] as is.
-  S afterError(S current, Object error) => current;
+  S afterError(S current, Object error, StackTrace stackTrace) => current;
 
   /// Returns an updated version of the [current] summary following stream
   /// termination.
@@ -138,9 +139,9 @@ class _StreamBuilderBaseState<T, S> extends State<StreamBuilderBase<T, S>> {
         setState(() {
           _summary = widget.afterData(_summary, data);
         });
-      }, onError: (Object error) {
+      }, onError: (Object error, StackTrace stackTrace) {
         setState(() {
-          _summary = widget.afterError(_summary, error);
+          _summary = widget.afterError(_summary, error, stackTrace);
         });
       }, onDone: () {
         setState(() {
@@ -204,22 +205,31 @@ enum ConnectionState {
 @immutable
 class AsyncSnapshot<T> {
   /// Creates an [AsyncSnapshot] with the specified [connectionState],
-  /// and optionally either [data] or [error] (but not both).
-  const AsyncSnapshot._(this.connectionState, this.data, this.error)
+  /// and optionally either [data] or [error] with an optional [stackTrace]
+  /// (but not both data and error).
+  const AsyncSnapshot._(this.connectionState, this.data, this.error, this.stackTrace)
     : assert(connectionState != null),
-      assert(!(data != null && error != null));
+      assert(!(data != null && error != null)),
+      assert(stackTrace == null || error != null);
 
   /// Creates an [AsyncSnapshot] in [ConnectionState.none] with null data and error.
-  const AsyncSnapshot.nothing() : this._(ConnectionState.none, null, null);
+  const AsyncSnapshot.nothing() : this._(ConnectionState.none, null, null, null);
 
   /// Creates an [AsyncSnapshot] in [ConnectionState.waiting] with null data and error.
-  const AsyncSnapshot.waiting() : this._(ConnectionState.waiting, null, null);
+  const AsyncSnapshot.waiting() : this._(ConnectionState.waiting, null, null, null);
 
   /// Creates an [AsyncSnapshot] in the specified [state] and with the specified [data].
-  const AsyncSnapshot.withData(ConnectionState state, T data): this._(state, data, null);
+  const AsyncSnapshot.withData(ConnectionState state, T data): this._(state, data, null, null);
 
-  /// Creates an [AsyncSnapshot] in the specified [state] and with the specified [error].
-  const AsyncSnapshot.withError(ConnectionState state, Object error) : this._(state, null, error);
+  /// Creates an [AsyncSnapshot] in the specified [state] with the specified [error]
+  /// and a [stackTrace].
+  ///
+  /// If no [stackTrace] is explicitly specified, [StackTrace.empty] will be used instead.
+  const AsyncSnapshot.withError(
+    ConnectionState state,
+    Object error, [
+    StackTrace stackTrace = StackTrace.empty,
+  ]) : this._(state, null, error, stackTrace);
 
   /// Current state of connection to the asynchronous computation.
   final ConnectionState connectionState;
@@ -254,11 +264,20 @@ class AsyncSnapshot<T> {
   /// If [data] is not null, this will be null.
   final Object? error;
 
+  /// The latest stack trace object received by the asynchronous computation.
+  ///
+  /// This will not be null iff [error] is not null. Consequently, [stackTrace]
+  /// will be non-null when [hasError] is true.
+  ///
+  /// However, even when not null, [stackTrace] might be empty. The stack trace
+  /// is empty when there is an error but no stack trace has been provided.
+  final StackTrace? stackTrace;
+
   /// Returns a snapshot like this one, but in the specified [state].
   ///
-  /// The [data] and [error] fields persist unmodified, even if the new state is
-  /// [ConnectionState.none].
-  AsyncSnapshot<T> inState(ConnectionState state) => AsyncSnapshot<T>._(state, data, error);
+  /// The [data], [error], and [stackTrace] fields persist unmodified, even if
+  /// the new state is [ConnectionState.none].
+  AsyncSnapshot<T> inState(ConnectionState state) => AsyncSnapshot<T>._(state, data, error, stackTrace);
 
   /// Returns whether this snapshot contains a non-null [data] value.
   ///
@@ -275,7 +294,7 @@ class AsyncSnapshot<T> {
   bool get hasError => error != null;
 
   @override
-  String toString() => '${objectRuntimeType(this, 'AsyncSnapshot')}($connectionState, $data, $error)';
+  String toString() => '${objectRuntimeType(this, 'AsyncSnapshot')}($connectionState, $data, $error, $stackTrace)';
 
   @override
   bool operator ==(Object other) {
@@ -284,7 +303,8 @@ class AsyncSnapshot<T> {
     return other is AsyncSnapshot<T>
         && other.connectionState == connectionState
         && other.data == data
-        && other.error == error;
+        && other.error == error
+        && other.stackTrace == stackTrace;
   }
 
   @override
@@ -318,12 +338,12 @@ typedef AsyncWidgetBuilder<T> = Widget Function(BuildContext context, AsyncSnaps
 /// of the following snapshots that includes the last one (the one with
 /// ConnectionState.done):
 ///
-/// * `new AsyncSnapshot<int>.withData(ConnectionState.waiting, null)`
-/// * `new AsyncSnapshot<int>.withData(ConnectionState.active, 0)`
-/// * `new AsyncSnapshot<int>.withData(ConnectionState.active, 1)`
+/// * `AsyncSnapshot<int>.withData(ConnectionState.waiting, null)`
+/// * `AsyncSnapshot<int>.withData(ConnectionState.active, 0)`
+/// * `AsyncSnapshot<int>.withData(ConnectionState.active, 1)`
 /// * ...
-/// * `new AsyncSnapshot<int>.withData(ConnectionState.active, 9)`
-/// * `new AsyncSnapshot<int>.withData(ConnectionState.done, 9)`
+/// * `AsyncSnapshot<int>.withData(ConnectionState.active, 9)`
+/// * `AsyncSnapshot<int>.withData(ConnectionState.done, 9)`
 ///
 /// The actual sequence of invocations of the [builder] depends on the relative
 /// timing of events produced by the stream and the build rate of the Flutter
@@ -332,15 +352,15 @@ typedef AsyncWidgetBuilder<T> = Widget Function(BuildContext context, AsyncSnaps
 /// Changing the [StreamBuilder] configuration to another stream during event
 /// generation introduces snapshot pairs of the form:
 ///
-/// * `new AsyncSnapshot<int>.withData(ConnectionState.none, 5)`
-/// * `new AsyncSnapshot<int>.withData(ConnectionState.waiting, 5)`
+/// * `AsyncSnapshot<int>.withData(ConnectionState.none, 5)`
+/// * `AsyncSnapshot<int>.withData(ConnectionState.waiting, 5)`
 ///
 /// The latter will be produced only when the new stream is non-null, and the
 /// former only when the old stream is non-null.
 ///
 /// The stream may produce errors, resulting in snapshots of the form:
 ///
-/// * `new AsyncSnapshot<int>.withError(ConnectionState.active, 'some error')`
+/// * `AsyncSnapshot<int>.withError(ConnectionState.active, 'some error', someStackTrace)`
 ///
 /// The data and error fields of snapshots produced are only changed when the
 /// state is `ConnectionState.active`.
@@ -386,7 +406,11 @@ typedef AsyncWidgetBuilder<T> = Widget Function(BuildContext context, AsyncSnaps
 ///               Padding(
 ///                 padding: const EdgeInsets.only(top: 16),
 ///                 child: Text('Error: ${snapshot.error}'),
-///               )
+///               ),
+///               Padding(
+///                 padding: const EdgeInsets.only(top: 8),
+///                 child: Text('Stack trace: ${snapshot.stackTrace}'),
+///               ),
 ///             ];
 ///           } else {
 ///             switch (snapshot.connectionState) {
@@ -511,8 +535,8 @@ class StreamBuilder<T> extends StreamBuilderBase<T, AsyncSnapshot<T>> {
   }
 
   @override
-  AsyncSnapshot<T> afterError(AsyncSnapshot<T> current, Object error) {
-    return AsyncSnapshot<T>.withError(ConnectionState.active, error);
+  AsyncSnapshot<T> afterError(AsyncSnapshot<T> current, Object error, StackTrace stackTrace) {
+    return AsyncSnapshot<T>.withError(ConnectionState.active, error, stackTrace);
   }
 
   @override
@@ -559,14 +583,14 @@ class StreamBuilder<T> extends StreamBuilderBase<T, AsyncSnapshot<T>> {
 /// is null, the [builder] will be called with either both or only the latter of
 /// the following snapshots:
 ///
-/// * `new AsyncSnapshot<String>.withData(ConnectionState.waiting, null)`
-/// * `new AsyncSnapshot<String>.withData(ConnectionState.done, 'some data')`
+/// * `AsyncSnapshot<String>.withData(ConnectionState.waiting, null)`
+/// * `AsyncSnapshot<String>.withData(ConnectionState.done, 'some data')`
 ///
 /// If that same future instead completed with an error, the [builder] would be
 /// called with either both or only the latter of:
 ///
-/// * `new AsyncSnapshot<String>.withData(ConnectionState.waiting, null)`
-/// * `new AsyncSnapshot<String>.withError(ConnectionState.done, 'some error')`
+/// * `AsyncSnapshot<String>.withData(ConnectionState.waiting, null)`
+/// * `AsyncSnapshot<String>.withError(ConnectionState.done, 'some error', someStackTrace)`
 ///
 /// The initial snapshot data can be controlled by specifying [initialData]. You
 /// would use this facility to ensure that if the [builder] is invoked before
@@ -579,8 +603,8 @@ class StreamBuilder<T> extends StreamBuilderBase<T, AsyncSnapshot<T>> {
 /// old future has already completed successfully with data as above, changing
 /// configuration to a new future results in snapshot pairs of the form:
 ///
-/// * `new AsyncSnapshot<String>.withData(ConnectionState.none, 'data of first future')`
-/// * `new AsyncSnapshot<String>.withData(ConnectionState.waiting, 'data of second future')`
+/// * `AsyncSnapshot<String>.withData(ConnectionState.none, 'data of first future')`
+/// * `AsyncSnapshot<String>.withData(ConnectionState.waiting, 'data of second future')`
 ///
 /// In general, the latter will be produced only when the new future is
 /// non-null, and the former only when the old future is non-null.
@@ -768,10 +792,10 @@ class _FutureBuilderState<T> extends State<FutureBuilder<T>> {
             _snapshot = AsyncSnapshot<T>.withData(ConnectionState.done, data);
           });
         }
-      }, onError: (Object error) {
+      }, onError: (Object error, StackTrace stackTrace) {
         if (_activeCallbackIdentity == callbackIdentity) {
           setState(() {
-            _snapshot = AsyncSnapshot<T>.withError(ConnectionState.done, error);
+            _snapshot = AsyncSnapshot<T>.withError(ConnectionState.done, error, stackTrace);
           });
         }
       });

packages/flutter/test/widgets/async_test.dart

@@ -34,9 +34,20 @@ void main() {
       expect(const AsyncSnapshot<int>.nothing().connectionState, ConnectionState.none);
       expect(const AsyncSnapshot<int>.nothing().data, isNull);
       expect(const AsyncSnapshot<int>.nothing().error, isNull);
+      expect(const AsyncSnapshot<int>.nothing().stackTrace, isNull);
       expect(const AsyncSnapshot<int>.waiting().connectionState, ConnectionState.waiting);
       expect(const AsyncSnapshot<int>.waiting().data, isNull);
       expect(const AsyncSnapshot<int>.waiting().error, isNull);
+      expect(const AsyncSnapshot<int>.waiting().stackTrace, isNull);
+    });
+    test('withError uses empty stack trace if no stack trace is specified', () {
+      // We need to store the error as a local variable in order for the
+      // equality check on the error to be true.
+      final Error error = Error();
+      expect(
+          AsyncSnapshot<int>.withError(ConnectionState.done, error),
+          AsyncSnapshot<int>.withError(
+              ConnectionState.done, error, StackTrace.empty));
     });
   });
   group('Async smoke tests', () {
@@ -67,12 +78,12 @@ void main() {
       await tester.pumpWidget(FutureBuilder<String>(
         key: key, future: null, builder: snapshotText,
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, null, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, null, null, null)'), findsOneWidget);
       final Completer<String> completer = Completer<String>();
       await tester.pumpWidget(FutureBuilder<String>(
         key: key, future: completer.future, builder: snapshotText,
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null, null)'), findsOneWidget);
     });
     testWidgets('gracefully handles transition to null future', (WidgetTester tester) async {
       final GlobalKey key = GlobalKey();
@@ -80,14 +91,14 @@ void main() {
       await tester.pumpWidget(FutureBuilder<String>(
         key: key, future: completer.future, builder: snapshotText,
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null, null)'), findsOneWidget);
       await tester.pumpWidget(FutureBuilder<String>(
         key: key, future: null, builder: snapshotText,
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, null, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, null, null, null)'), findsOneWidget);
       completer.complete('hello');
       await eventFiring(tester);
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, null, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, null, null, null)'), findsOneWidget);
     });
     testWidgets('gracefully handles transition to other future', (WidgetTester tester) async {
       final GlobalKey key = GlobalKey();
@@ -96,35 +107,35 @@ void main() {
       await tester.pumpWidget(FutureBuilder<String>(
         key: key, future: completerA.future, builder: snapshotText,
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null, null)'), findsOneWidget);
       await tester.pumpWidget(FutureBuilder<String>(
         key: key, future: completerB.future, builder: snapshotText,
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null, null)'), findsOneWidget);
       completerB.complete('B');
       completerA.complete('A');
       await eventFiring(tester);
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.done, B, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.done, B, null, null)'), findsOneWidget);
     });
     testWidgets('tracks life-cycle of Future to success', (WidgetTester tester) async {
       final Completer<String> completer = Completer<String>();
       await tester.pumpWidget(FutureBuilder<String>(
         future: completer.future, builder: snapshotText,
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null, null)'), findsOneWidget);
       completer.complete('hello');
       await eventFiring(tester);
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.done, hello, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.done, hello, null, null)'), findsOneWidget);
     });
     testWidgets('tracks life-cycle of Future to error', (WidgetTester tester) async {
       final Completer<String> completer = Completer<String>();
       await tester.pumpWidget(FutureBuilder<String>(
         future: completer.future, builder: snapshotText,
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null)'), findsOneWidget);
-      completer.completeError('bad');
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null, null)'), findsOneWidget);
+      completer.completeError('bad', StackTrace.fromString('trace'));
       await eventFiring(tester);
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.done, null, bad)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.done, null, bad, trace)'), findsOneWidget);
     });
     testWidgets('runs the builder using given initial data', (WidgetTester tester) async {
       final GlobalKey key = GlobalKey();
@@ -134,7 +145,7 @@ void main() {
         builder: snapshotText,
         initialData: 'I',
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, I, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, I, null, null)'), findsOneWidget);
     });
     testWidgets('ignores initialData when reconfiguring', (WidgetTester tester) async {
       final GlobalKey key = GlobalKey();
@@ -144,7 +155,7 @@ void main() {
         builder: snapshotText,
         initialData: 'I',
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, I, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, I, null, null)'), findsOneWidget);
       final Completer<String> completer = Completer<String>();
       await tester.pumpWidget(FutureBuilder<String>(
         key: key,
@@ -152,7 +163,7 @@ void main() {
         builder: snapshotText,
         initialData: 'Ignored',
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, I, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, I, null, null)'), findsOneWidget);
     });
   });
   group('StreamBuilder', () {
@@ -161,12 +172,12 @@ void main() {
       await tester.pumpWidget(StreamBuilder<String>(
         key: key, stream: null, builder: snapshotText,
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, null, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, null, null, null)'), findsOneWidget);
       final StreamController<String> controller = StreamController<String>();
       await tester.pumpWidget(StreamBuilder<String>(
         key: key, stream: controller.stream, builder: snapshotText,
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null, null)'), findsOneWidget);
     });
     testWidgets('gracefully handles transition to null stream', (WidgetTester tester) async {
       final GlobalKey key = GlobalKey();
@@ -174,11 +185,11 @@ void main() {
       await tester.pumpWidget(StreamBuilder<String>(
         key: key, stream: controller.stream, builder: snapshotText,
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null, null)'), findsOneWidget);
       await tester.pumpWidget(StreamBuilder<String>(
         key: key, stream: null, builder: snapshotText,
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, null, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, null, null, null)'), findsOneWidget);
     });
     testWidgets('gracefully handles transition to other stream', (WidgetTester tester) async {
       final GlobalKey key = GlobalKey();
@@ -187,14 +198,14 @@ void main() {
       await tester.pumpWidget(StreamBuilder<String>(
         key: key, stream: controllerA.stream, builder: snapshotText,
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null, null)'), findsOneWidget);
       await tester.pumpWidget(StreamBuilder<String>(
         key: key, stream: controllerB.stream, builder: snapshotText,
       ));
       controllerB.add('B');
       controllerA.add('A');
       await eventFiring(tester);
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.active, B, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.active, B, null, null)'), findsOneWidget);
     });
     testWidgets('tracks events and errors of stream until completion', (WidgetTester tester) async {
       final GlobalKey key = GlobalKey();
@@ -202,19 +213,19 @@ void main() {
       await tester.pumpWidget(StreamBuilder<String>(
         key: key, stream: controller.stream, builder: snapshotText,
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null, null)'), findsOneWidget);
       controller.add('1');
       controller.add('2');
       await eventFiring(tester);
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.active, 2, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.active, 2, null, null)'), findsOneWidget);
       controller.add('3');
-      controller.addError('bad');
+      controller.addError('bad', StackTrace.fromString('trace'));
       await eventFiring(tester);
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.active, null, bad)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.active, null, bad, trace)'), findsOneWidget);
       controller.add('4');
       controller.close();
       await eventFiring(tester);
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.done, 4, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.done, 4, null, null)'), findsOneWidget);
     });
     testWidgets('runs the builder using given initial data', (WidgetTester tester) async {
       final StreamController<String> controller = StreamController<String>();
@@ -223,7 +234,7 @@ void main() {
         builder: snapshotText,
         initialData: 'I',
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, I, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, I, null, null)'), findsOneWidget);
     });
     testWidgets('ignores initialData when reconfiguring', (WidgetTester tester) async {
       final GlobalKey key = GlobalKey();
@@ -233,7 +244,7 @@ void main() {
         builder: snapshotText,
         initialData: 'I',
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, I, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, I, null, null)'), findsOneWidget);
       final StreamController<String> controller = StreamController<String>();
       await tester.pumpWidget(StreamBuilder<String>(
         key: key,
@@ -241,7 +252,7 @@ void main() {
         builder: snapshotText,
         initialData: 'Ignored',
       ));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, I, null)'), findsOneWidget);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, I, null, null)'), findsOneWidget);
     });
   });
   group('FutureBuilder and StreamBuilder behave identically on Stream from Future', () {
@@ -251,35 +262,46 @@ void main() {
         FutureBuilder<String>(future: completer.future, builder: snapshotText),
         StreamBuilder<String>(stream: completer.future.asStream(), builder: snapshotText),
       ]));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null)'), findsNWidgets(2));
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null, null)'), findsNWidgets(2));
       completer.complete('hello');
       await eventFiring(tester);
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.done, hello, null)'), findsNWidgets(2));
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.done, hello, null, null)'), findsNWidgets(2));
+    });
+    testWidgets('when completing with error and with empty stack trace', (WidgetTester tester) async {
+      final Completer<String> completer = Completer<String>();
+      await tester.pumpWidget(Column(children: <Widget>[
+        FutureBuilder<String>(future: completer.future, builder: snapshotText),
+        StreamBuilder<String>(stream: completer.future.asStream(), builder: snapshotText),
+      ]));
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null, null)'), findsNWidgets(2));
+      completer.completeError('bad', StackTrace.empty);
+      await eventFiring(tester);
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.done, null, bad, )'), findsNWidgets(2));
     });
-    testWidgets('when completing with error', (WidgetTester tester) async {
+    testWidgets('when completing with error and with stack trace', (WidgetTester tester) async {
       final Completer<String> completer = Completer<String>();
       await tester.pumpWidget(Column(children: <Widget>[
         FutureBuilder<String>(future: completer.future, builder: snapshotText),
         StreamBuilder<String>(stream: completer.future.asStream(), builder: snapshotText),
       ]));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null)'), findsNWidgets(2));
-      completer.completeError('bad');
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, null, null, null)'), findsNWidgets(2));
+      completer.completeError('bad', StackTrace.fromString('trace'));
       await eventFiring(tester);
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.done, null, bad)'), findsNWidgets(2));
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.done, null, bad, trace)'), findsNWidgets(2));
     });
     testWidgets('when Future is null', (WidgetTester tester) async {
       await tester.pumpWidget(Column(children: <Widget>[
         FutureBuilder<String>(future: null, builder: snapshotText),
         StreamBuilder<String>(stream: null, builder: snapshotText),
       ]));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, null, null)'), findsNWidgets(2));
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, null, null, null)'), findsNWidgets(2));
     });
     testWidgets('when initialData is used with null Future and Stream', (WidgetTester tester) async {
       await tester.pumpWidget(Column(children: <Widget>[
         FutureBuilder<String>(future: null, builder: snapshotText, initialData: 'I'),
         StreamBuilder<String>(stream: null, builder: snapshotText, initialData: 'I'),
       ]));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, I, null)'), findsNWidgets(2));
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.none, I, null, null)'), findsNWidgets(2));
     });
     testWidgets('when using initialData and completing with data', (WidgetTester tester) async {
       final Completer<String> completer = Completer<String>();
@@ -287,10 +309,10 @@ void main() {
         FutureBuilder<String>(future: completer.future, builder: snapshotText, initialData: 'I'),
         StreamBuilder<String>(stream: completer.future.asStream(), builder: snapshotText, initialData: 'I'),
       ]));
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, I, null)'), findsNWidgets(2));
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.waiting, I, null, null)'), findsNWidgets(2));
       completer.complete('hello');
       await eventFiring(tester);
-      expect(find.text('AsyncSnapshot<String>(ConnectionState.done, hello, null)'), findsNWidgets(2));
+      expect(find.text('AsyncSnapshot<String>(ConnectionState.done, hello, null, null)'), findsNWidgets(2));
     });
   });
   group('StreamBuilderBase', () {
@@ -326,11 +348,11 @@ void main() {
       final StreamController<String> controller = StreamController<String>();
       await tester.pumpWidget(StringCollector(key: key, stream: controller.stream));
       controller.add('1');
-      controller.addError('bad');
+      controller.addError('bad', StackTrace.fromString('trace'));
       controller.add('2');
       controller.close();
       await eventFiring(tester);
-      expect(find.text('conn, data:1, error:bad, data:2, done'), findsOneWidget);
+      expect(find.text('conn, data:1, error:bad stackTrace:trace, data:2, done'), findsOneWidget);
     });
   });
 }
@@ -352,7 +374,7 @@ class StringCollector extends StreamBuilderBase<String, List<String>> {
   List<String> afterData(List<String> current, String data) => current..add('data:$data');
 
   @override
-  List<String> afterError(List<String> current, dynamic error) => current..add('error:$error');
+  List<String> afterError(List<String> current, dynamic error, StackTrace stackTrace) => current..add('error:$error stackTrace:$stackTrace');
 
   @override
   List<String> afterDone(List<String> current) => current..add('done');