From 1d4bd35424d312e864109378f0ee0c8bab4f9ced Mon Sep 17 00:00:00 2001
From: LeoTM <1881059+leotm@users.noreply.github.com>
Date: Mon, 28 Oct 2024 17:53:53 +0000
Subject: [PATCH 1/2] fix(ses): expect fn instance prototype on Hermes in
 permit

---
 packages/ses/src/permits.js | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/packages/ses/src/permits.js b/packages/ses/src/permits.js
index fa62aaa7ea..e842f43f7a 100644
--- a/packages/ses/src/permits.js
+++ b/packages/ses/src/permits.js
@@ -270,6 +270,9 @@ export const FunctionInstance = {
   // Do not specify "prototype" here, since only Function instances that can
   // be used as a constructor have a prototype property. For constructors,
   // since prototype properties are instance-specific, we define it there.
+  // Older versions of Hermes contain a non-standard prototype, noted below in 'hermesFn'.
+  // This is fixed fully in Static Hermes: https://github.com/facebook/hermes/tree/static_h
+  // See: https://speakerdeck.com/tmikov2023/optimizing-with-static-hermes-chain-react-2024
 };
 
 // AsyncFunction Instances
@@ -281,6 +284,14 @@ export const AsyncFunctionInstance = {
 
 // Aliases
 const fn = FunctionInstance;
+// Bypass Hermes bugs, fixed in:
+// - https://github.com/facebook/hermes/commit/c42491de94aff479e5e83c073eff96a6261da080 (hermes: v0.13.0)
+// - https://github.com/facebook/hermes/commit/00f18c89c720e1c34592bb85a1a8d311e6e99599 (sh_stable, static_h)
+// Expect Additional Properties of the Global Object (Annex B) proposed by SES,
+// that are function instances defined as arrow functions ('lockdown' and 'harden')
+// and concise methods ('%InitialGetStackString%'), to have their non-standard
+// prototype properties set to `undefined` in intrinsics.js when completing prototypes.
+const hermesFn = { ...FunctionInstance, prototype: 'undefined' };
 const asyncFn = AsyncFunctionInstance;
 
 const getter = {
@@ -1643,8 +1654,8 @@ export const permitted = {
     '@@toStringTag': 'string',
   },
 
-  lockdown: fn,
-  harden: { ...fn, isFake: 'boolean' },
+  lockdown: hermesFn,
+  harden: { ...hermesFn, isFake: 'boolean' },
 
-  '%InitialGetStackString%': fn,
+  '%InitialGetStackString%': hermesFn,
 };

From 048efd377d6ed0714251d9b6ff81a1c6620b8995 Mon Sep 17 00:00:00 2001
From: LeoTM <1881059+leotm@users.noreply.github.com>
Date: Mon, 28 Oct 2024 17:54:07 +0000
Subject: [PATCH 2/2] fix(ses): set fn instance prototype to undefined on
 Hermes

---
 packages/ses/src/intrinsics.js | 33 ++++++++++++++++++++++++---------
 1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/packages/ses/src/intrinsics.js b/packages/ses/src/intrinsics.js
index 4355d0c6ab..c74697f725 100644
--- a/packages/ses/src/intrinsics.js
+++ b/packages/ses/src/intrinsics.js
@@ -98,25 +98,40 @@ export const makeIntrinsicsCollector = () => {
       if (typeof permit !== 'object') {
         throw TypeError(`Expected permit object at whitelist.${name}`);
       }
-      const namePrototype = permit.prototype;
-      if (!namePrototype) {
+      const permitPrototype = permit.prototype;
+
+      if (
+        typeof intrinsic === 'function' &&
+        intrinsic.prototype !== undefined &&
+        permitPrototype === 'undefined' // permits.js
+      ) {
+        // Set non-standard `.prototype` properties to `undefined` on Hermes.
+        // These include intrinsics that are additional properties of the global object,
+        // proposed by SES defined as function instances
+        // - arrow functions: lockdown, harden
+        // - concise methods: %InitialGetStackString%
+        intrinsic.prototype = undefined;
+      }
+
+      const intrinsicPrototype = intrinsic.prototype;
+
+      if (!permitPrototype) {
         throw TypeError(`${name}.prototype property not whitelisted`);
       }
       if (
-        typeof namePrototype !== 'string' ||
-        !objectHasOwnProperty(permitted, namePrototype)
+        typeof permitPrototype !== 'string' ||
+        !objectHasOwnProperty(permitted, permitPrototype)
       ) {
         throw TypeError(`Unrecognized ${name}.prototype whitelist entry`);
       }
-      const intrinsicPrototype = intrinsic.prototype;
-      if (objectHasOwnProperty(intrinsics, namePrototype)) {
-        if (intrinsics[namePrototype] !== intrinsicPrototype) {
-          throw TypeError(`Conflicting bindings of ${namePrototype}`);
+      if (objectHasOwnProperty(intrinsics, permitPrototype)) {
+        if (intrinsics[permitPrototype] !== intrinsicPrototype) {
+          throw TypeError(`Conflicting bindings of ${permitPrototype}`);
         }
         // eslint-disable-next-line no-continue
         continue;
       }
-      intrinsics[namePrototype] = intrinsicPrototype;
+      intrinsics[permitPrototype] = intrinsicPrototype;
     }
   };
   freeze(completePrototypes);