From a07959033ea9fce98a1d907108d448a841987421 Mon Sep 17 00:00:00 2001
From: Anna Henningsen <anna@addaleax.net>
Date: Sat, 11 Jul 2020 14:19:38 +0200
Subject: [PATCH 1/2] worker: fix nested uncaught exception handling
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We are using `ObjectPrototypeToString()` as a cross-context brand check
for built-in errors, but weren’t making sure to set that when
deserializing errors back into JS objects.

Fix that by setting `[Symbol.toStringTag]` manually, to make sure that
multiple serialize-and-deserialize cycles keep giving the same result.

Fixes: https://github.com/nodejs/node/issues/34309
---
 lib/internal/error_serdes.js                 |  4 ++++
 test/parallel/test-error-serdes.js           |  9 +++++++--
 test/parallel/test-worker-nested-uncaught.js | 14 ++++++++++++++
 3 files changed, 25 insertions(+), 2 deletions(-)
 create mode 100644 test/parallel/test-worker-nested-uncaught.js

diff --git a/lib/internal/error_serdes.js b/lib/internal/error_serdes.js
index 72e8c12e9a7358..d0128cb80892c4 100644
--- a/lib/internal/error_serdes.js
+++ b/lib/internal/error_serdes.js
@@ -116,6 +116,10 @@ function deserializeError(error) {
     case kSerializedError:
       const { constructor, properties } = deserialize(error.subarray(1));
       const ctor = errors[constructor];
+      ObjectDefineProperty(properties, Symbol.toStringTag, {
+        value: { value: 'Error', configurable: true },
+        enumerable: true
+      });
       return ObjectCreate(ctor.prototype, properties);
     case kSerializedObject:
       return deserialize(error.subarray(1));
diff --git a/test/parallel/test-error-serdes.js b/test/parallel/test-error-serdes.js
index 262afc9f389358..f01dc0d6a8a81d 100644
--- a/test/parallel/test-error-serdes.js
+++ b/test/parallel/test-error-serdes.js
@@ -16,12 +16,17 @@ assert.strictEqual(cycle(null), null);
 assert.strictEqual(cycle(undefined), undefined);
 assert.strictEqual(cycle('foo'), 'foo');
 
-{
-  const err = cycle(new Error('foo'));
+let err = new Error('foo');
+for (let i = 0; i < 10; i++) {
   assert(err instanceof Error);
+  assert(Object.prototype.toString.call(err), '[object Error]');
   assert.strictEqual(err.name, 'Error');
   assert.strictEqual(err.message, 'foo');
   assert(/^Error: foo\n/.test(err.stack));
+
+  const prev = err;
+  err = cycle(err);
+  assert.deepStrictEqual(err, prev);
 }
 
 assert.strictEqual(cycle(new RangeError('foo')).name, 'RangeError');
diff --git a/test/parallel/test-worker-nested-uncaught.js b/test/parallel/test-worker-nested-uncaught.js
new file mode 100644
index 00000000000000..2559b85ee1e6aa
--- /dev/null
+++ b/test/parallel/test-worker-nested-uncaught.js
@@ -0,0 +1,14 @@
+'use strict';
+const common = require('../common');
+const { Worker } = require('worker_threads');
+
+// Regression test for https://github.com/nodejs/node/issues/34309
+
+const w = new Worker(
+  `const { Worker } = require('worker_threads');
+  new Worker("throw new Error('uncaught')", { eval:true })`,
+  { eval: true });
+w.on('error', common.expectsError({
+    name: 'Error',
+    message: 'uncaught'
+  }));

From ee7775abbf3500a7c519db588e59432e8e750091 Mon Sep 17 00:00:00 2001
From: Anna Henningsen <anna@addaleax.net>
Date: Sat, 11 Jul 2020 14:27:15 +0200
Subject: [PATCH 2/2] fixup! worker: fix nested uncaught exception handling

---
 lib/internal/error_serdes.js                 | 3 ++-
 test/parallel/test-worker-nested-uncaught.js | 6 +++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/lib/internal/error_serdes.js b/lib/internal/error_serdes.js
index d0128cb80892c4..5e18448da7046c 100644
--- a/lib/internal/error_serdes.js
+++ b/lib/internal/error_serdes.js
@@ -14,6 +14,7 @@ const {
   ObjectKeys,
   ObjectPrototypeToString,
   SafeSet,
+  SymbolToStringTag,
 } = primordials;
 
 const kSerializedError = 0;
@@ -116,7 +117,7 @@ function deserializeError(error) {
     case kSerializedError:
       const { constructor, properties } = deserialize(error.subarray(1));
       const ctor = errors[constructor];
-      ObjectDefineProperty(properties, Symbol.toStringTag, {
+      ObjectDefineProperty(properties, SymbolToStringTag, {
         value: { value: 'Error', configurable: true },
         enumerable: true
       });
diff --git a/test/parallel/test-worker-nested-uncaught.js b/test/parallel/test-worker-nested-uncaught.js
index 2559b85ee1e6aa..00bb6832203442 100644
--- a/test/parallel/test-worker-nested-uncaught.js
+++ b/test/parallel/test-worker-nested-uncaught.js
@@ -9,6 +9,6 @@ const w = new Worker(
   new Worker("throw new Error('uncaught')", { eval:true })`,
   { eval: true });
 w.on('error', common.expectsError({
-    name: 'Error',
-    message: 'uncaught'
-  }));
+  name: 'Error',
+  message: 'uncaught'
+}));