From b7ecb0a390894736937343e7b08808e3b5ff2bd9 Mon Sep 17 00:00:00 2001
From: Khafra <maitken033380023@gmail.com>
Date: Fri, 27 Oct 2023 17:37:32 -0400
Subject: [PATCH] src: readiterable entries may be empty
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

fixup

PR-URL: https://github.com/nodejs/node/pull/50398
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Vinícius Lourenço Claro Cardoso <contact@viniciusl.com.br>
Reviewed-By: Debadree Chatterjee <debadree333@gmail.com>
---
 src/node_messaging.cc                        |  7 +++++--
 test/parallel/test-messagechannel.js         | 12 ++++++++++++
 test/parallel/test-structuredClone-global.js | 11 +++++++++++
 3 files changed, 28 insertions(+), 2 deletions(-)
 create mode 100644 test/parallel/test-messagechannel.js

diff --git a/src/node_messaging.cc b/src/node_messaging.cc
index 1a5ca8efd0beb3..04b998bb28ce4b 100644
--- a/src/node_messaging.cc
+++ b/src/node_messaging.cc
@@ -994,8 +994,11 @@ static Maybe<bool> ReadIterable(Environment* env,
     entries.push_back(val);
   }
 
-  transfer_list.AllocateSufficientStorage(entries.size());
-  std::copy(entries.begin(), entries.end(), &transfer_list[0]);
+  if (!entries.empty()) {
+    transfer_list.AllocateSufficientStorage(entries.size());
+    std::copy(entries.begin(), entries.end(), &transfer_list[0]);
+  }
+
   return Just(true);
 }
 
diff --git a/test/parallel/test-messagechannel.js b/test/parallel/test-messagechannel.js
new file mode 100644
index 00000000000000..4f92924daa5048
--- /dev/null
+++ b/test/parallel/test-messagechannel.js
@@ -0,0 +1,12 @@
+'use strict';
+
+const common = require('../common');
+
+// See: https://github.com/nodejs/node/issues/49940
+(async () => {
+  new MessageChannel().port1.postMessage({}, {
+    transfer: {
+      *[Symbol.iterator]() {}
+    }
+  });
+})().then(common.mustCall());
diff --git a/test/parallel/test-structuredClone-global.js b/test/parallel/test-structuredClone-global.js
index 2b49a7a2e70696..7a4d85b6c177f0 100644
--- a/test/parallel/test-structuredClone-global.js
+++ b/test/parallel/test-structuredClone-global.js
@@ -15,3 +15,14 @@ assert.strictEqual(structuredClone(undefined, null), undefined);
 // Transfer can be null or undefined.
 assert.strictEqual(structuredClone(undefined, { transfer: null }), undefined);
 assert.strictEqual(structuredClone(undefined, { }), undefined);
+
+{
+  // See: https://github.com/nodejs/node/issues/49940
+  const cloned = structuredClone({}, {
+    transfer: {
+      *[Symbol.iterator]() {}
+    }
+  });
+
+  assert.deepStrictEqual(cloned, {});
+}