From 3ec652ad3817a9d995b29321f90c101793af71d1 Mon Sep 17 00:00:00 2001
From: Anatoli Papirovski <anatoli.papirovski@postmates.com>
Date: Sun, 17 Mar 2019 11:26:01 -0700
Subject: [PATCH] timers: fix refresh inside callback

When `timers.refresh()` is called inside a callback, the timer would
incorrectly end up unrefed and thus not keep the event loop alive.

PR-URL: https://github.com/nodejs/node/pull/26721
Fixes: https://github.com/nodejs/node/issues/26642
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Weijia Wang <starkwang@126.com>
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
---
 lib/internal/timers.js                           |  2 +-
 test/parallel/test-timers-refresh-in-callback.js | 14 ++++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)
 create mode 100644 test/parallel/test-timers-refresh-in-callback.js

diff --git a/lib/internal/timers.js b/lib/internal/timers.js
index eaacc01c205080..ce3519ac8e1db2 100644
--- a/lib/internal/timers.js
+++ b/lib/internal/timers.js
@@ -469,7 +469,7 @@ function getTimerCallbacks(runNextTicks) {
           if (start === undefined)
             start = getLibuvNow();
           insert(timer, timer[kRefed], start);
-        } else {
+        } else if (!timer._idleNext && !timer._idlePrev) {
           if (timer[kRefed])
             refCount--;
           timer[kRefed] = null;
diff --git a/test/parallel/test-timers-refresh-in-callback.js b/test/parallel/test-timers-refresh-in-callback.js
new file mode 100644
index 00000000000000..df62512acd60b1
--- /dev/null
+++ b/test/parallel/test-timers-refresh-in-callback.js
@@ -0,0 +1,14 @@
+'use strict';
+
+const common = require('../common');
+
+// This test checks whether a refresh called inside the callback will keep
+// the event loop alive to run the timer again.
+
+let didCall = false;
+const timer = setTimeout(common.mustCall(() => {
+  if (!didCall) {
+    didCall = true;
+    timer.refresh();
+  }
+}, 2), 1);