repl: fix some repl context issues

This partially fixes contexts like `{} instanceof Object === false`
in the REPL. This does not fix all cases, since it's something
fundamental from the REPL's design that things like these can happen.

Refs: https://github.com/nodejs/node/issues/27859

PR-URL: https://github.com/nodejs/node/pull/28561
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/lib/repl.js b/lib/repl.js
index 85692d718f..d1b9a91df6 100644
--- a/lib/repl.js
+++ b/lib/repl.js
@@ -875,8 +875,11 @@ REPLServer.prototype.createContext = function() {
       context = vm.createContext();
     });
     for (const name of Object.getOwnPropertyNames(global)) {
-      Object.defineProperty(context, name,
-                            Object.getOwnPropertyDescriptor(global, name));
+      // Only set properties on the context that do not exist as primordial.
+      if (!(name in primordials)) {
+        Object.defineProperty(context, name,
+                              Object.getOwnPropertyDescriptor(global, name));
+      }
     }
     context.global = context;
     const _console = new Console(this.outputStream);