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fix: tolerate empty func.prototype #1221
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if (obj.prototype === undefined) { | ||
// eslint-disable-next-line @endo/no-polymorphic-call | ||
console.warn(`Tolerating undeletable ${subPath} === undefined`); |
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Will this not always warn?
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Hmm. Unless the prototype: 'undefined'
property is explicitly defined in the whitelist?
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In any case, for present purposes, I prefer that it always warn.
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Oh, I see the context.
|
||
test('tolerate empty prototype', t => { | ||
t.assert('prototype' in Array.prototype.push); | ||
t.is(Array.prototype.push.prototype, undefined); |
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Array.prototype.push.prototype
here is not set to undefined
, so it's an object, no?
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Ah, clear.
See zloirock/core-js#1092
If a primordial method is whitelisted as
fn
, then it is not supposed to haveprototype
property. However, as explained by zloirock/core-js#1092 , there is some desire to runcore-js
as a vetted shim, i.e., a shim run beforelockdown
that does not break any of the invariants that SES depends on. However, the core-js shim also targets ES5, and there's no good option in ES5 for making a replacement primordial function that does not have an undeletableprototype
property.With this PR, our whitelisting, on encountering such a function, instead sets its
prototype
toundefined
and then checks that it has done so. If so, then it issues a warning but allows the whitelisting to continue.