Function prototype set to undefined inconsistently too late

[leotm]

Describe the bug

On Hermes we never reach (in whitelistIntrinsics)

endo/packages/ses/src/permits-intrinsics.js

Lines 303 to 304 in b3a31b1

	if (typeof obj === 'function' && prop === 'prototype') {
	obj.prototype = undefined;

but reach here first instead

endo/packages/ses/src/intrinsics.js

Lines 87 to 103 in b3a31b1

	const completePrototypes = () => {
	for (const [name, intrinsic] of entries(intrinsics)) {
	if (!isObject(intrinsic)) {
	// eslint-disable-next-line no-continue
	continue;
	}
	if (!objectHasOwnProperty(intrinsic, 'prototype')) {
	// eslint-disable-next-line no-continue
	continue;
	}
	const permit = permitted[name];
	if (typeof permit !== 'object') {
	throw TypeError(`Expected permit object at whitelist.${name}`);
	}
	const namePrototype = permit.prototype;
	if (!namePrototype) {
	throw TypeError(`${name}.prototype property not whitelisted`);

order of events and conditions

• intrinsics.js > completePrototypes
  • isObject(intrinsic)
  • objectHasOwnProperty(intrinsic, 'prototype')
  • typeof permit === 'object'
  • !permit.prototype
    • throw TypeError(`${name}.prototype property not whitelisted`);
• permit-intrinsics.js > whitelistIntrinsics
  • prop in obj
  • typeof obj === 'function' && prop === 'prototype'
    • obj.prototype = undefined (not reached)
    • fix: tolerate empty func.prototype #1221

Steps to reproduce

• feat(ses): Shim compatible with Hermes compiler #2334
  • yarn build:hermes && yarn test:hermes

Expected behavior

The prototype to be set to undefined earlier
so we continue which skips throwing the TypeError

Platform environment

• macOS Sequoia 15.0.1
• Node v20.12.2
• Hermes v0.12.0 (lockdown), v0.13.0 (harden)
• @endo/base64@1.0.8-10-gb3a31b155

Additional context

• fix(ses): completePrototypes on Hermes #2563 (comment)

Note: on Static Hermes this is a non-issue, since both prototype bugs are fixed

Screenshots