From 576c970e2f71554a1f748b9208ff7a3f0596e822 Mon Sep 17 00:00:00 2001
From: Matteo Collina <matteo.collina@gmail.com>
Date: Sun, 29 Jul 2018 09:48:16 -0700
Subject: [PATCH] Do not cast to string Error#stack. (#464)

---
 pino.js            |  4 +++-
 test/error.test.js | 16 ++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/pino.js b/pino.js
index ff34c3b30..43b68b6a5 100644
--- a/pino.js
+++ b/pino.js
@@ -147,7 +147,9 @@ function asJson (obj, msg, num, time) {
     var notHasOwnProperty = obj.hasOwnProperty === undefined
     if (objError) {
       data += ',"type":"Error"'
-      data += obj.stack ? ',"stack":' + this.stringify(obj.stack) : ''
+      if (obj.stack !== undefined) {
+        data += ',"stack":' + this.stringify(obj.stack)
+      }
     }
     // if global serializer is set, call it first
     if (this.serializers[Symbol.for('pino.*')]) {
diff --git a/test/error.test.js b/test/error.test.js
index dbdf1bc84..5bdb73d5a 100644
--- a/test/error.test.js
+++ b/test/error.test.js
@@ -143,3 +143,19 @@ test('stack is omitted if it is not set on err', t => {
   instance.level = name
   instance[name](err)
 })
+
+test('stack is rendered as any other property if it\'s not a string', t => {
+  t.plan(3)
+  var err = new Error('myerror')
+  err.stack = null
+  var instance = pino(sink(function (chunk, enc, cb) {
+    t.ok(new Date(chunk.time) <= new Date(), 'time is greater than Date.now()')
+    delete chunk.time
+    t.equal(chunk.hasOwnProperty('stack'), true)
+    t.equal(chunk.stack, null)
+    cb()
+  }))
+
+  instance.level = name
+  instance[name](err)
+})