From 99d8a14df682b2a93a26216b0fab7d7c4bef1100 Mon Sep 17 00:00:00 2001
From: Simon Knott <info@simonknott.de>
Date: Tue, 5 Dec 2023 09:08:09 +0100
Subject: [PATCH 1/2] fix: only emit prototype pollution error when there's
 metadata emitted

---
 src/index.test.ts |  7 ++++++-
 src/plainer.ts    | 22 ++++++++++++----------
 2 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/src/index.test.ts b/src/index.test.ts
index e314728..7fa8ebf 100644
--- a/src/index.test.ts
+++ b/src/index.test.ts
@@ -1059,7 +1059,7 @@ test.each(['__proto__', 'prototype', 'constructor'])(
   forbidden => {
     expect(() => {
       SuperJSON.serialize({
-        [forbidden]: 1,
+        [forbidden]: NaN,
       });
     }).toThrowError(/This is a prototype pollution risk/);
   }
@@ -1229,3 +1229,8 @@ test('dedupe=true on a large complicated schema', () => {
   expect(nondedupedOut).toEqual(deserialized);
   expect(dedupedOut).toEqual(deserialized);
 });
+
+test("prototype pollution detector doesn't trigger when there's no meta", () => {
+  const { meta } = SuperJSON.serialize({ constructor: { name: 'hello' } });
+  expect(meta).toBeUndefined();
+});
diff --git a/src/plainer.ts b/src/plainer.ts
index 114d76a..3c3c2ae 100644
--- a/src/plainer.ts
+++ b/src/plainer.ts
@@ -216,16 +216,6 @@ export const walker = (
   const innerAnnotations: Record<string, Tree<TypeAnnotation>> = {};
 
   forEach(transformed, (value, index) => {
-    if (
-      index === '__proto__' ||
-      index === 'constructor' ||
-      index === 'prototype'
-    ) {
-      throw new Error(
-        `Detected property ${index}. This is a prototype pollution risk, please remove it from your object.`
-      );
-    }
-
     const recursiveResult = walker(
       value,
       identities,
@@ -236,6 +226,18 @@ export const walker = (
       seenObjects
     );
 
+    const emitsMeta = recursiveResult.annotations !== undefined;
+    if (
+      emitsMeta &&
+      (index === '__proto__' ||
+        index === 'constructor' ||
+        index === 'prototype')
+    ) {
+      throw new Error(
+        `Detected property ${index}. This is a prototype pollution risk, please remove it from your object.`
+      );
+    }
+
     transformedValue[index] = recursiveResult.transformedValue;
 
     if (isArray(recursiveResult.annotations)) {

From 5fa55b76a742540f1b00dc1951418a4880608171 Mon Sep 17 00:00:00 2001
From: Simon Knott <info@simonknott.de>
Date: Wed, 6 Dec 2023 12:08:06 +0100
Subject: [PATCH 2/2] fix: add repro for
 https://github.com/blitz-js/superjson/issues/279#issuecomment-1842647002

---
 src/index.test.ts | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/index.test.ts b/src/index.test.ts
index 7fa8ebf..af7f484 100644
--- a/src/index.test.ts
+++ b/src/index.test.ts
@@ -686,6 +686,21 @@ describe('stringify & parse', () => {
         },
       },
     },
+    'repro #281': {
+      input: {
+        schema: { constructor: { type: 'string' } },
+        createdAt: new Date('2023-12-06T10:49:28.911Z'),
+      },
+      output: {
+        schema: { constructor: { type: 'string' } },
+        createdAt: '2023-12-06T10:49:28.911Z',
+      },
+      outputAnnotations: {
+        values: {
+          createdAt: ['Date'],
+        },
+      },
+    },
   };
 
   function deepFreeze(object: any, alreadySeenObjects = new Set()) {