From 07dbf7313d0b46bf4452c63aee72f91ea587598c Mon Sep 17 00:00:00 2001
From: James M Snell <jasnell@gmail.com>
Date: Sun, 21 Aug 2016 21:16:40 -0700
Subject: [PATCH] promise: hard deprecation for unhandled promise rejection

PR-URL: https://github.com/nodejs/node/pull/8217
Reviewed-By: Chris Dickinson <christopher.s.dickinson@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
---
 lib/internal/process/promises.js                         | 9 +++++++++
 .../test-promises-warning-on-unhandled-rejection.js      | 5 ++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/lib/internal/process/promises.js b/lib/internal/process/promises.js
index 02c90a928bbc64..e364822fa3a7bf 100644
--- a/lib/internal/process/promises.js
+++ b/lib/internal/process/promises.js
@@ -45,6 +45,7 @@ function setupPromises(scheduleMicrotasks) {
     }
   }
 
+  var deprecationWarned = false;
   function emitPendingUnhandledRejections() {
     let hadListeners = false;
     while (pendingUnhandledRejections.length > 0) {
@@ -59,6 +60,14 @@ function setupPromises(scheduleMicrotasks) {
           warning.name = 'UnhandledPromiseRejectionWarning';
           warning.id = uid;
           process.emitWarning(warning);
+          if (!deprecationWarned) {
+            deprecationWarned = true;
+            process.emitWarning(
+              'Unhandled promise rejections are deprecated. In the future, ' +
+              'promise rejections that are not handled will terminate the ' +
+              'Node.js process with a non-zero exit code.',
+              'DeprecationWarning');
+          }
         } else {
           hadListeners = true;
         }
diff --git a/test/parallel/test-promises-warning-on-unhandled-rejection.js b/test/parallel/test-promises-warning-on-unhandled-rejection.js
index 9b1e7f3266aba0..b50a5cae416942 100644
--- a/test/parallel/test-promises-warning-on-unhandled-rejection.js
+++ b/test/parallel/test-promises-warning-on-unhandled-rejection.js
@@ -16,11 +16,14 @@ process.on('warning', common.mustCall((warning) => {
       assert(/Unhandled promise rejection/.test(warning.message));
       break;
     case 1:
+      assert.strictEqual(warning.name, 'DeprecationWarning');
+      break;
+    case 2:
       assert.strictEqual(warning.name, 'PromiseRejectionHandledWarning');
       assert(/Promise rejection was handled asynchronously/
         .test(warning.message));
   }
-}, 2));
+}, 3));
 
 const p = Promise.reject('This was rejected');
 setImmediate(common.mustCall(() => p.catch(() => {})));