v8/test/mjsunit/harmony/weakrefs/weakref-deref-keeps-alive.js
Marja Hölttä fef6f8eddc [js weak refs] Migrate the WeakRef parts into the new API
New API is here: https://github.com/tc39/proposal-weakrefs/issues/55

The WeakCell parts stay in the old API, resulting in temporary code duplication
in some parts. Those parts will go away once the WeakCell-related parts are
migrated to the new API (but the spec needs some work first).

BUG=v8:8179

Change-Id: I81ca824a14d830e3c5fa515d5ad7e5f78c10e19d
Reviewed-on: https://chromium-review.googlesource.com/c/1378171
Commit-Queue: Marja Hölttä <marja@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58264}
2018-12-17 08:58:56 +00:00

46 lines
1.0 KiB
JavaScript

// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Flags: --harmony-weak-refs --expose-gc --noincremental-marking --allow-natives-syntax
let wr;
let wr_control; // control WeakRef for testing what happens without deref
(function() {
let o1 = {};
wr = new WeakRef(o1);
let o2 = {};
wr_control = new WeakRef(o2);
})();
let strong = {a: wr.deref(), b: wr_control.deref()};
gc();
%PerformMicrotaskCheckpoint();
// Next turn.
// Call deref inside a closure, trying to avoid accidentally storing a strong
// reference into the object in the stack frame.
(function() {
wr.deref();
})();
strong = null;
// This GC will clear wr_control.
gc();
(function() {
assertNotEquals(undefined, wr.deref());
// Now the control WeakRef got cleared, since nothing was keeping it alive.
assertEquals(undefined, wr_control.deref());
})();
%PerformMicrotaskCheckpoint();
// Next turn.
gc();
assertEquals(undefined, wr.deref());