From 02bdacef42bbaeeaea1ef5a6c1588d5f934cbb5c Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Mon, 2 Sep 2019 13:18:39 +0200
Subject: [PATCH] Ensure that `Error`s are handled correctly when using
 `postMessage` with Streams in `MessageHandler`

Having recently worked with this code, it struck me that most of the `postMessage` calls where `Error`s are involved have never been correctly implemented (i.e. missing `wrapReason` calls).
---
 src/shared/message_handler.js     | 10 +++++-----
 test/unit/message_handler_spec.js | 10 ++++++----
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/src/shared/message_handler.js b/src/shared/message_handler.js
index 2a7a64d0b..ee4122649 100644
--- a/src/shared/message_handler.js
+++ b/src/shared/message_handler.js
@@ -231,7 +231,7 @@ MessageHandler.prototype = {
           targetName,
           stream: StreamKind.CANCEL,
           streamId,
-          reason,
+          reason: wrapReason(reason),
         });
         // Return Promise to signal success or failure.
         return cancelCapability.promise;
@@ -296,7 +296,7 @@ MessageHandler.prototype = {
           targetName,
           stream: StreamKind.ERROR,
           streamId,
-          reason,
+          reason: wrapReason(reason),
         });
       },
 
@@ -327,7 +327,7 @@ MessageHandler.prototype = {
         targetName,
         stream: StreamKind.START_COMPLETE,
         streamId,
-        reason,
+        reason: wrapReason(reason),
       });
     });
   },
@@ -397,7 +397,7 @@ MessageHandler.prototype = {
             targetName,
             stream: StreamKind.PULL_COMPLETE,
             streamId,
-            reason,
+            reason: wrapReason(reason),
           });
         });
         break;
@@ -450,7 +450,7 @@ MessageHandler.prototype = {
             targetName,
             stream: StreamKind.CANCEL_COMPLETE,
             streamId,
-            reason,
+            reason: wrapReason(reason),
           });
         });
         this.streamSinks[data.streamId].sinkCapability.
diff --git a/test/unit/message_handler_spec.js b/test/unit/message_handler_spec.js
index f9465791f..908391e10 100644
--- a/test/unit/message_handler_spec.js
+++ b/test/unit/message_handler_spec.js
@@ -142,11 +142,13 @@ describe('message_handler', function () {
         sink.onCancel = function (reason) {
           log += 'c';
         };
+        log += '0';
         sink.ready.then(() => {
+          log += '1';
           sink.enqueue([1, 2, 3, 4], 4);
           return sink.ready;
         }).then(() => {
-          log += 'error';
+          log += 'e';
           sink.error('error');
         });
       });
@@ -161,14 +163,14 @@ describe('message_handler', function () {
       let reader = readable.getReader();
 
       sleep(10).then(() => {
-        expect(log).toEqual('');
+        expect(log).toEqual('01');
         return reader.read();
       }).then((result) => {
         expect(result.value).toEqual([1, 2, 3, 4]);
         expect(result.done).toEqual(false);
         return reader.read();
-      }).then(() => {
-      }, (reason) => {
+      }).catch((reason) => {
+        expect(log).toEqual('01pe');
         expect(reason).toEqual('error');
         done();
       });