fix: microtasks policy in CreateEnvironment (#29531)

* fix: microtasks policy in CreateEnvironment

Microtasks policy should not be updated for the renderer because
`NodeBindings::CreateEnvironment` might be entered with or without
`UvRunOnce()` on stack. One of the examples of such calls is
`window.open()` which is possible to invoke while `uv_run()` is still
running (e.g. with `setImmediate()`).

All in all, it doesn't matter that much which policy we use since
`v8::MicrotasksScope` has a check for the policy in its destructor and
no commits will be made if the policy is `kExplicit`. It is important,
however, to not change the policy in the middle of `UvRunOnce()` so we
should respect whatever we currently have and move on.

Fix: #29463

* Move test to a better place

* Update spec-main/fixtures/crash-cases/setimmediate-window-open-crash/index.html

Co-authored-by: Jeremy Rose <nornagon@nornagon.net>

* Update spec-main/fixtures/crash-cases/setimmediate-window-open-crash/index.html

Co-authored-by: Jeremy Rose <nornagon@nornagon.net>

* simplify crash-case

* comment

* fix comment

Co-authored-by: Fedor Indutny <79877362+indutny-signal@users.noreply.github.com>
Co-authored-by: Jeremy Rose <nornagon@nornagon.net>
Co-authored-by: Fedor Indutny <indutny@signal.org>
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Fedor Indutny 2021-06-20 22:06:17 -07:00 committed by GitHub
parent cfc846a337
commit d4a1b41129
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3 changed files with 49 additions and 3 deletions

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@ -482,9 +482,13 @@ node::Environment* NodeBindings::CreateEnvironment(
// Node.js requires that microtask checkpoints be explicitly invoked.
is.policy = v8::MicrotasksPolicy::kExplicit;
} else {
// Match Blink's behavior by allowing microtasks invocation to be controlled
// by MicrotasksScope objects.
is.policy = v8::MicrotasksPolicy::kScoped;
// Blink expects the microtasks policy to be kScoped, but Node.js expects it
// to be kExplicit. In the renderer, there can be many contexts within the
// same isolate, so we don't want to change the existing policy here, which
// could be either kExplicit or kScoped depending on whether we're executing
// from within a Node.js or a Blink entrypoint. Instead, the policy is
// toggled to kExplicit when entering Node.js through UvRunOnce.
is.policy = context->GetIsolate()->GetMicrotasksPolicy();
// We do not want to use Node.js' message listener as it interferes with
// Blink's.