From b54edaf8d3f81a26d1e935751d96222fc0f611f9 Mon Sep 17 00:00:00 2001
From: Charles Kerr <ckerr@github.com>
Date: Fri, 17 Apr 2020 05:11:57 -0500
Subject: [PATCH] fix: use Node's microtasks policy in node_main.cc

Fixes #21515.
---
 shell/app/node_main.cc                     |  4 ++++
 spec-main/node-spec.ts                     | 13 ++++++++++++
 spec/fixtures/module/node-promise-timer.js | 23 ++++++++++++++++++++++
 3 files changed, 40 insertions(+)
 create mode 100644 spec/fixtures/module/node-promise-timer.js

diff --git a/shell/app/node_main.cc b/shell/app/node_main.cc
index 5e8c1c2aaaa1c..c9dcd64cdb68e 100644
--- a/shell/app/node_main.cc
+++ b/shell/app/node_main.cc
@@ -146,6 +146,10 @@ int NodeMain(int argc, char* argv[]) {
     JavascriptEnvironment gin_env(loop);
 
     v8::Isolate* isolate = gin_env.isolate();
+    // TODO(ckerr) and/or TODO(codebytere) use node::SetIsolateMiscHandlers()
+    node::IsolateSettings is;
+    isolate->SetMicrotasksPolicy(is.policy);
+
     v8::Isolate::Scope isolate_scope(isolate);
     v8::Locker locker(isolate);
     node::Environment* env = nullptr;
diff --git a/spec-main/node-spec.ts b/spec-main/node-spec.ts
index d6030e76f7b7a..50811de6eeb59 100644
--- a/spec-main/node-spec.ts
+++ b/spec-main/node-spec.ts
@@ -307,4 +307,17 @@ describe('node feature', () => {
     const result = childProcess.spawnSync(process.execPath, [path.resolve(fixtures, 'api', 'electron-main-module', 'app.asar')]);
     expect(result.status).to.equal(0);
   });
+
+  it('handles Promise timeouts correctly', (done) => {
+    const scriptPath = path.join(fixtures, 'module', 'node-promise-timer.js');
+    const child = childProcess.spawn(process.execPath, [scriptPath], {
+      env: { ELECTRON_RUN_AS_NODE: 'true' }
+    });
+    emittedOnce(child, 'exit').then(([code, signal]) => {
+      expect(code).to.equal(0);
+      expect(signal).to.equal(null);
+      child.kill();
+      done();
+    });
+  });
 });
diff --git a/spec/fixtures/module/node-promise-timer.js b/spec/fixtures/module/node-promise-timer.js
new file mode 100644
index 0000000000000..b21c24f5dfc36
--- /dev/null
+++ b/spec/fixtures/module/node-promise-timer.js
@@ -0,0 +1,23 @@
+const waitMs = (msec) => new Promise((resolve) => setTimeout(resolve, msec));
+
+const intervalMsec = 100;
+const numIterations = 2;
+let curIteration = 0;
+let promise;
+
+for (let i = 0; i < numIterations; i++) {
+  promise = (promise || waitMs(intervalMsec)).then(() => {
+    ++curIteration;
+    return waitMs(intervalMsec);
+  });
+}
+
+// https://github.com/electron/electron/issues/21515 was about electron
+// exiting before promises finished. This test sets the pending exitCode
+// to failure, then resets it to success only if all promises finish.
+process.exitCode = 1;
+promise.then(() => {
+  if (curIteration === numIterations) {
+    process.exitCode = 0;
+  }
+});