From f36e8593dd46295237da94b28714dc11ec3c603b Mon Sep 17 00:00:00 2001
From: Anna Henningsen <anna@addaleax.net>
Date: Tue, 29 Oct 2019 21:24:23 +0100
Subject: [PATCH 1/2] v8: inspect unserializable objects

This would otherwise sometimes just print relatively useless
information about the value in question, such as `[object Object]`.
---
 lib/v8.js                       | 4 +++-
 test/parallel/test-v8-serdes.js | 6 ++++--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/lib/v8.js b/lib/v8.js
index 1a8c70c6d75d3f..5be59cb935cfcf 100644
--- a/lib/v8.js
+++ b/lib/v8.js
@@ -24,6 +24,7 @@ const {
 } = internalBinding('serdes');
 const assert = require('internal/assert');
 const { copy } = internalBinding('buffer');
+const { inspect } = require('internal/util/inspect');
 const { FastBuffer } = require('internal/buffer');
 const { getValidatedPath } = require('internal/fs/utils');
 const { toNamespacedPath } = require('path');
@@ -242,7 +243,8 @@ class DefaultSerializer extends Serializer {
       i = arrayBufferViewTypeToIndex.get(tag);
 
       if (i === undefined) {
-        throw new this._getDataCloneError(`Unknown host object type: ${tag}`);
+        throw new this._getDataCloneError(
+          `Unserializable host object: ${inspect(abView)}`);
       }
     }
     this.writeUint32(i);
diff --git a/test/parallel/test-v8-serdes.js b/test/parallel/test-v8-serdes.js
index 58b919066ea990..8be5aed22df6bc 100644
--- a/test/parallel/test-v8-serdes.js
+++ b/test/parallel/test-v8-serdes.js
@@ -156,8 +156,10 @@ const deserializerTypeError =
 }
 
 {
-  assert.throws(() => v8.serialize(hostObject),
-                /^Error: Unknown host object type: \[object .*\]$/);
+  assert.throws(() => v8.serialize(hostObject), {
+                  constructor: Error,
+                  message: 'Unserializable host object: JSStream {}'
+                });
 }
 
 {

From 001ae3459572e79a18787707911136dfe9f5a031 Mon Sep 17 00:00:00 2001
From: Anna Henningsen <anna@addaleax.net>
Date: Fri, 1 Nov 2019 20:16:47 +0100
Subject: [PATCH 2/2] fixup! v8: inspect unserializable objects

---
 test/parallel/test-v8-serdes.js | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/test/parallel/test-v8-serdes.js b/test/parallel/test-v8-serdes.js
index 8be5aed22df6bc..a992ba42ce46bf 100644
--- a/test/parallel/test-v8-serdes.js
+++ b/test/parallel/test-v8-serdes.js
@@ -157,9 +157,9 @@ const deserializerTypeError =
 
 {
   assert.throws(() => v8.serialize(hostObject), {
-                  constructor: Error,
-                  message: 'Unserializable host object: JSStream {}'
-                });
+    constructor: Error,
+    message: 'Unserializable host object: JSStream {}'
+  });
 }
 
 {