From 575cd60c5d1322604430b89681d37989e2f34239 Mon Sep 17 00:00:00 2001
From: LeoTM <1881059+leotm@users.noreply.github.com>
Date: Thu, 24 Oct 2024 01:55:31 +0100
Subject: [PATCH] refactor(ses): document Hermes bugs and fixes for intrinsics

---
 packages/ses/src/intrinsics.js | 4 +++-
 packages/ses/src/permits.js    | 7 ++++++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/packages/ses/src/intrinsics.js b/packages/ses/src/intrinsics.js
index 6f44637b7a..aaf4c7d58d 100644
--- a/packages/ses/src/intrinsics.js
+++ b/packages/ses/src/intrinsics.js
@@ -100,12 +100,14 @@ export const makeIntrinsicsCollector = () => {
       }
       const permitPrototype = permit.prototype;
 
-      // Bypass Hermes bug, fixed in: https://github.com/facebook/hermes/commit/00f18c89c720e1c34592bb85a1a8d311e6e99599
       if (
         typeof intrinsic === 'function' &&
         intrinsic.prototype !== undefined &&
         permitPrototype === 'undefined' // permits.js
       ) {
+        // Set intrinsics that are additional function properties of the global Object proposed by SES to have non-standard prototype properties set to undefined.
+        // Set Hermes additional function intrinsics proposed by SES containing non-standard prototypes to undefined.
+        // This includes arrow functions (lockdown and harden) and object literal methods (%InitialGetStackString%).
         intrinsic.prototype = undefined;
       }
 
diff --git a/packages/ses/src/permits.js b/packages/ses/src/permits.js
index d25c737236..7c3e952848 100644
--- a/packages/ses/src/permits.js
+++ b/packages/ses/src/permits.js
@@ -282,7 +282,12 @@ export const AsyncFunctionInstance = {
 
 // Aliases
 const fn = FunctionInstance;
-const hermesFn = { ...FunctionInstance, prototype: 'undefined' }; // Bypass Hermes bug, fixed in: https://github.com/facebook/hermes/commit/00f18c89c720e1c34592bb85a1a8d311e6e99599
+// Bypass Hermes bugs, fixed in:
+// - https://github.com/facebook/hermes/commit/c42491de94aff479e5e83c073eff96a6261da080
+// - https://github.com/facebook/hermes/commit/00f18c89c720e1c34592bb85a1a8d311e6e99599
+// Expect additional Function Properties of the Global Object proposed by SES to have non-standard prototype properties set to undefined.
+// This includes arrow functions (lockdown and harden) and object literal methods (%InitialGetStackString%).
+const hermesFn = { ...FunctionInstance, prototype: 'undefined' };
 const asyncFn = AsyncFunctionInstance;
 
 const getter = {