From 391aeb1996330886c671f0946377a03365e87af7 Mon Sep 17 00:00:00 2001
From: Antoine du Hamel <duhamelantoine1995@gmail.com>
Date: Fri, 19 Jan 2024 09:42:07 +0100
Subject: [PATCH] module: fix crash when built-in module export a `default` key

PR-URL: https://github.com/nodejs/node/pull/51481
Fixes: https://github.com/nodejs/node/issues/51480
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Guy Bedford <guybedford@gmail.com>
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
---
 lib/internal/bootstrap/realm.js       | 4 +++-
 test/parallel/test-process-default.js | 8 ++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 test/parallel/test-process-default.js

diff --git a/lib/internal/bootstrap/realm.js b/lib/internal/bootstrap/realm.js
index 57ab47178d033d..f030f537a084d7 100644
--- a/lib/internal/bootstrap/realm.js
+++ b/lib/internal/bootstrap/realm.js
@@ -350,7 +350,9 @@ class BuiltinModule {
     const url = `node:${this.id}`;
     const builtin = this;
     const exportsKeys = ArrayPrototypeSlice(this.exportKeys);
-    ArrayPrototypePush(exportsKeys, 'default');
+    if (!ArrayPrototypeIncludes(exportsKeys, 'default')) {
+      ArrayPrototypePush(exportsKeys, 'default');
+    }
     this.module = new ModuleWrap(
       url, undefined, exportsKeys,
       function() {
diff --git a/test/parallel/test-process-default.js b/test/parallel/test-process-default.js
new file mode 100644
index 00000000000000..a6ceda2af3ee25
--- /dev/null
+++ b/test/parallel/test-process-default.js
@@ -0,0 +1,8 @@
+'use strict';
+const common = require('../common');
+const assert = require('node:assert');
+
+process.default = 1;
+import('node:process').then(common.mustCall((processModule) => {
+  assert.strictEqual(processModule.default.default, 1);
+}));