per-realm.js - mozsearch

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// Copyright (C) 2026 Igalia, S.L. All rights reserved.

// This code is governed by the BSD license found in the LICENSE file.

/*---

esid: intl-object

description: "%Intl%.[[FallbackSymbol]] is per-realm"

info: |

  The Intl object:

  - has a [[FallbackSymbol]] internal slot, which is a new %Symbol% in the

    current realm with the [[Description]] *"IntlLegacyConstructedSymbol"*.

features: [intl-normative-optional]

---*/

const fallbackDTF = Intl.DateTimeFormat.call(Object.create(Intl.DateTimeFormat.prototype));

const symbolProps = Object.getOwnPropertySymbols(fallbackDTF);

const fallbackSymbol = symbolProps.find((sym) => sym.description === "IntlLegacyConstructedSymbol");

assert.notSameValue(fallbackSymbol, undefined, "%Intl%.[[FallbackSymbol]] should exist in original realm");

const other = $262.createRealm();

const otherFallbackSymbol = other.evalScript(`

  const fallbackDTF = Intl.DateTimeFormat.call(Object.create(Intl.DateTimeFormat.prototype));

  const symbolProps = Object.getOwnPropertySymbols(fallbackDTF);

  symbolProps.find((sym) => sym.description === "IntlLegacyConstructedSymbol");

`);

assert.notSameValue(otherFallbackSymbol, undefined, "%Intl%.[[FallbackSymbol]] should exist in new realm");

assert.notSameValue(fallbackSymbol, otherFallbackSymbol, "%Intl%.[[FallbackSymbol]] should be different per-realm");

reportCompare(0, 0);