From 90e8f79f652b02a8fdf6f72e273cc81429a9376a Mon Sep 17 00:00:00 2001
From: Bryan English <bryan@bryanenglish.com>
Date: Wed, 4 Apr 2018 14:47:08 -0700
Subject: [PATCH] constants: freeze the constants object

Constants ought to be constant. The primary goal of this commit is to
make constants exposed in require('constants') immutable, as they were
prior to node@7.0.0, and as the constants exposed on fs.constants,
crypto.constants, etc. are.

Since this is implemented by using Object.freeze, it also has the side
effect of making the entire exports of require('constants') immutable,
so no new constants can be defined on the object in userland.

PR-URL: https://github.com/nodejs/node/pull/19813
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Ali Ijaz Sheikh <ofrobots@google.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
---
 lib/constants.js                | 1 +
 test/parallel/test-constants.js | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/lib/constants.js b/lib/constants.js
index 3336fd8d7fc..dee46126447 100644
--- a/lib/constants.js
+++ b/lib/constants.js
@@ -32,3 +32,4 @@ Object.assign(exports,
               constants.os.signals,
               constants.fs,
               constants.crypto);
+Object.freeze(exports);
diff --git a/test/parallel/test-constants.js b/test/parallel/test-constants.js
index c11935783f8..945443d8866 100644
--- a/test/parallel/test-constants.js
+++ b/test/parallel/test-constants.js
@@ -24,3 +24,5 @@ assert.ok(binding.crypto);
     }
   });
 });
+
+assert.ok(Object.isFrozen(constants));