From 331681a3f526742874a88fc63d2fc6f2b64964fb Mon Sep 17 00:00:00 2001
From: Trevor Norris <trev.norris@gmail.com>
Date: Wed, 14 Dec 2016 17:17:10 -0700
Subject: [PATCH] src: return early if nextTickQueue is empty

This brings the node::MakeCallback and node::AsyncWrap::MakeCallback
implementations into alignment in that they return early if the
nextTickQueue is empty after processing the MicrotaskQueue.

Include test to make sure early return happens. Test has text explaining
the conditions for the test to pass, since it relies on internal
mechanisms that aren't guaranteed in the future.

PR-URL: https://github.com/nodejs/node/pull/10274
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
---
 src/node.cc                                 |  1 +
 test/parallel/test-no-enter-tickcallback.js | 32 +++++++++++++++++++++
 2 files changed, 33 insertions(+)
 create mode 100644 test/parallel/test-no-enter-tickcallback.js

diff --git a/src/node.cc b/src/node.cc
index 6ca8ee95e2..0b972d0a97 100644
--- a/src/node.cc
+++ b/src/node.cc
@@ -1317,6 +1317,7 @@ Local<Value> MakeCallback(Environment* env,
 
   if (tick_info->length() == 0) {
     tick_info->set_index(0);
+    return ret;
   }
 
   if (env->tick_callback_function()->Call(process, 0, nullptr).IsEmpty()) {
diff --git a/test/parallel/test-no-enter-tickcallback.js b/test/parallel/test-no-enter-tickcallback.js
new file mode 100644
index 0000000000..aab22c5f3e
--- /dev/null
+++ b/test/parallel/test-no-enter-tickcallback.js
@@ -0,0 +1,32 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+let allsGood = false;
+let cntr = 0;
+
+process.on('exit', () => {
+  assert.ok(cntr > 0, '_tickDomainCallback was never called');
+});
+
+/**
+ * This test relies upon the following internals to work as specified:
+ *  - require('domain') causes node::Environment::set_tick_callback_function()
+ *    to use process._tickDomainCallback() to process the nextTickQueue;
+ *    replacing process._tickCallback().
+ *  - setImmediate() uses node::MakeCallback() instead of
+ *    node::AsyncWrap::MakeCallback(). Otherwise the test will always pass.
+ *    Have not found a way to verify that node::MakeCallback() is used.
+ */
+process._tickDomainCallback = function _tickDomainCallback() {
+  assert.ok(allsGood, '_tickDomainCallback should not have been called');
+  cntr++;
+};
+
+setImmediate(common.mustCall(() => {
+  require('domain');
+  setImmediate(common.mustCall(() => setImmediate(common.mustCall(() => {
+    allsGood = true;
+    process.nextTick(() => {});
+  }))));
+}));