From f2fe5583c434e9864a1171209908c3a24b9d54bb Mon Sep 17 00:00:00 2001
From: Nikolai Vavilov <vvnicholas@gmail.com>
Date: Thu, 18 Aug 2016 22:03:56 +0300
Subject: [PATCH] buffer: runtime deprecation of calling Buffer without new
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

PR-URL: https://github.com/nodejs/node/pull/8169
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Stephen Belanger <admin@stephenbelanger.com>
Reviewed-By: Сковорода Никита Андреевич <chalkerx@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
---
 lib/buffer.js                           | 10 ++++++++++
 test/parallel/test-buffer-deprecated.js | 17 +++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 test/parallel/test-buffer-deprecated.js

diff --git a/lib/buffer.js b/lib/buffer.js
index c5e5a4e58fe296..e41e3662662609 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -64,7 +64,17 @@ function alignPool() {
  * much breakage at this time. It's not likely that the Buffer constructors
  * would ever actually be removed.
  **/
+var newBufferWarned = false;
 function Buffer(arg, encodingOrOffset, length) {
+  if (!new.target && !newBufferWarned) {
+    newBufferWarned = true;
+    process.emitWarning(
+      'Using Buffer without `new` will soon stop working. ' +
+      'Use `new Buffer()`, or preferably ' +
+      '`Buffer.from()`, `Buffer.allocUnsafe()` or `Buffer.alloc()` instead.',
+      'DeprecationWarning'
+    );
+  }
   // Common case.
   if (typeof arg === 'number') {
     if (typeof encodingOrOffset === 'string') {
diff --git a/test/parallel/test-buffer-deprecated.js b/test/parallel/test-buffer-deprecated.js
new file mode 100644
index 00000000000000..21a9ce9ed6dcd6
--- /dev/null
+++ b/test/parallel/test-buffer-deprecated.js
@@ -0,0 +1,17 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+
+const expected =
+  'Using Buffer without `new` will soon stop working. ' +
+  'Use `new Buffer()`, or preferably ' +
+  '`Buffer.from()`, `Buffer.allocUnsafe()` or `Buffer.alloc()` instead.';
+
+process.on('warning', common.mustCall((warning) => {
+  assert.strictEqual(warning.name, 'DeprecationWarning');
+  assert.strictEqual(warning.message, expected,
+                     `unexpected error message: "${warning.message}"`);
+}, 1));
+
+Buffer(1);
+Buffer(1);