Be more explicit about JSON error handling. R=rnystrom@google.com Review URL: https://codereview.chromium.org//1658833002 .

diff --git a/pkgs/stream_channel/CHANGELOG.md b/pkgs/stream_channel/CHANGELOG.md
index c85bbe3..d101ea0 100644
--- a/pkgs/stream_channel/CHANGELOG.md
+++ b/pkgs/stream_channel/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.0.2
+
+* Be more explicit about `JsonDocumentTransformer`'s error-handling behavior.
+
 ## 1.0.1
 
 * Fix `MultiChannel`'s constructor to take a `StreamChannel`. This is

diff --git a/pkgs/stream_channel/lib/src/json_document_transformer.dart b/pkgs/stream_channel/lib/src/json_document_transformer.dart
index 8d8dcce..19b2e08 100644
--- a/pkgs/stream_channel/lib/src/json_document_transformer.dart
+++ b/pkgs/stream_channel/lib/src/json_document_transformer.dart

@@ -17,6 +17,10 @@
 ///
 /// This decodes JSON that's emitted by the transformed channel's stream, and
 /// encodes objects so that JSON is passed to the transformed channel's sink.
+///
+/// If the transformed channel emits invalid JSON, this emits a
+/// [FormatException]. If an unencodable object is added to the sink, it
+/// synchronously throws a [JsonUnsupportedObjectError].
 class JsonDocumentTransformer
     implements StreamChannelTransformer<String, Object> {
   /// The underlying codec that implements the encoding and decoding logic.

diff --git a/pkgs/stream_channel/pubspec.yaml b/pkgs/stream_channel/pubspec.yaml
index 09df4a7..54e9198 100644
--- a/pkgs/stream_channel/pubspec.yaml
+++ b/pkgs/stream_channel/pubspec.yaml

@@ -1,5 +1,5 @@
 name: stream_channel
-version: 1.0.1
+version: 1.0.2
 description: An abstraction for two-way communication channels.
 author: Dart Team <misc@dartlang.org>
 homepage: https://github.com/dart-lang/stream_channel

diff --git a/pkgs/stream_channel/test/json_document_transformer_test.dart b/pkgs/stream_channel/test/json_document_transformer_test.dart
index fec3d2a..65a3497 100644
--- a/pkgs/stream_channel/test/json_document_transformer_test.dart
+++ b/pkgs/stream_channel/test/json_document_transformer_test.dart

@@ -47,4 +47,16 @@
     transformed.sink.add(new Object());
     expect(sinkController.stream.first, completion(equals('"encoded"')));
   });
+
+  test("emits a stream error when incoming JSON is malformed", () {
+    var transformed = channel.transform(jsonDocument);
+    streamController.add("{invalid");
+    expect(transformed.stream.first, throwsFormatException);
+  });
+
+  test("synchronously throws if an unencodable object is added", () {
+    var transformed = channel.transform(jsonDocument);
+    expect(() => transformed.sink.add(new Object()),
+        throwsA(new isInstanceOf<JsonUnsupportedObjectError>()));
+  });
 }