From 7cf6f9e964aa00772965391c23acda6d71972a9a Mon Sep 17 00:00:00 2001
From: cjihrig <cjihrig@gmail.com>
Date: Thu, 4 Jul 2019 16:20:20 -0400
Subject: [PATCH] process: refactor unhandledRejection logic

This commit prevents a deprecation warning from being emitted
if the unhandledRejection event was actually handled.

PR-URL: https://github.com/nodejs/node/pull/28540
Fixes: https://github.com/nodejs/node/issues/28539
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Masashi Hirano <shisama07@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
---
 lib/internal/process/promises.js                       | 10 ++++++----
 .../test-promise-handled-rejection-no-warning.js       |  8 ++++++++
 2 files changed, 14 insertions(+), 4 deletions(-)
 create mode 100644 test/parallel/test-promise-handled-rejection-no-warning.js

diff --git a/lib/internal/process/promises.js b/lib/internal/process/promises.js
index ee54594ba3c66b..ab833776070449 100644
--- a/lib/internal/process/promises.js
+++ b/lib/internal/process/promises.js
@@ -199,10 +199,12 @@ function processPromiseRejections() {
       }
       case kDefaultUnhandledRejections: {
         const handled = process.emit('unhandledRejection', reason, promise);
-        if (!handled) emitUnhandledRejectionWarning(uid, reason);
-        if (!deprecationWarned) {
-          emitDeprecationWarning();
-          deprecationWarned = true;
+        if (!handled) {
+          emitUnhandledRejectionWarning(uid, reason);
+          if (!deprecationWarned) {
+            emitDeprecationWarning();
+            deprecationWarned = true;
+          }
         }
         break;
       }
diff --git a/test/parallel/test-promise-handled-rejection-no-warning.js b/test/parallel/test-promise-handled-rejection-no-warning.js
new file mode 100644
index 00000000000000..14b06affb73825
--- /dev/null
+++ b/test/parallel/test-promise-handled-rejection-no-warning.js
@@ -0,0 +1,8 @@
+'use strict';
+const common = require('../common');
+
+// This test verifies that DEP0018 does not occur when rejections are handled.
+common.disableCrashOnUnhandledRejection();
+process.on('warning', common.mustNotCall());
+process.on('unhandledRejection', common.mustCall());
+Promise.reject(new Error());