From 8f39dbc699a3a20f9be47823e9012854cb144b12 Mon Sep 17 00:00:00 2001
From: Petka Antonov <petka_antonov@hotmail.com>
Date: Sun, 26 May 2019 11:36:48 +0300
Subject: [PATCH] Fixes #1326

---
 .jshintrc        |  2 ++
 src/constants.js |  5 ++++-
 src/promise.js   | 10 +++++++++-
 src/reduce.js    |  7 +++++++
 4 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/.jshintrc b/.jshintrc
index 601adc6ff..bc1449713 100644
--- a/.jshintrc
+++ b/.jshintrc
@@ -88,7 +88,9 @@
         "CALLBACK_PROMISE_OFFSET": false,
         "CALLBACK_RECEIVER_OFFSET": false,
         "CALLBACK_SIZE": false,
+        "ASYNC_GUARANTEE_SHIFT": false,
         "NO_STATE": false,
+        "NO_ASYNC_GUARANTEE": false,
         "RETURNED_NON_UNDEFINED": false,
         "IS_ASYNC_GUARANTEED": false,
         "IS_FOLLOWING": false,
diff --git a/src/constants.js b/src/constants.js
index 63ad1b3d6..a011036cf 100644
--- a/src/constants.js
+++ b/src/constants.js
@@ -28,10 +28,11 @@ CONSTANT(CALLBACK_PROMISE_OFFSET, 2);
 CONSTANT(CALLBACK_RECEIVER_OFFSET, 3);
 CONSTANT(CALLBACK_SIZE, 4);
 //Layout for ._bitField
-//[RR]RO GWFN CTBH IUDE LLLL LLLL LLLL LLLL
+//[RR]XO GWFN CTBH IUDE LLLL LLLL LLLL LLLL
 //[RR] = [Reserved] (Both bits are either on or off to represent
 //                    1 bit due to 31-bit integers in 32-bit v8)
 //R = [Reserved]
+//X = noAsyncGuarantee
 //O = returnedNonUndefined
 //G = isAsyncGuaranteed
 //W = isFollowing (The promise that is being followed is not stored explicitly)
@@ -46,7 +47,9 @@ CONSTANT(CALLBACK_SIZE, 4);
 //D = isDisposable
 //E = isCancelled
 //L = Length, 16 bit unsigned
+CONSTANT(ASYNC_GUARANTEE_SHIFT, 2)
 CONSTANT(NO_STATE, 0x0|0);
+CONSTANT(NO_ASYNC_GUARANTEE, 0x20000000|0);
 CONSTANT(RETURNED_NON_UNDEFINED, 0x10000000|0);
 CONSTANT(IS_ASYNC_GUARANTEED, 0x8000000|0);
 CONSTANT(IS_FOLLOWING, 0x4000000|0);
diff --git a/src/promise.js b/src/promise.js
index c1f5d251d..f511f4856 100644
--- a/src/promise.js
+++ b/src/promise.js
@@ -360,7 +360,15 @@ Promise.prototype._setWillBeCancelled = function() {
 
 Promise.prototype._setAsyncGuaranteed = function() {
     if (async.hasCustomScheduler()) return;
-    this._bitField = this._bitField | IS_ASYNC_GUARANTEED;
+    var bitField = this._bitField;
+    this._bitField = bitField |
+        (((bitField & NO_ASYNC_GUARANTEE) >> ASYNC_GUARANTEE_SHIFT) ^
+        IS_ASYNC_GUARANTEED);
+};
+
+Promise.prototype._setNoAsyncGuarantee = function() {
+    this._bitField = (this._bitField | NO_ASYNC_GUARANTEE) &
+        (~IS_ASYNC_GUARANTEED);
 };
 
 Promise.prototype._receiverAt = function (index) {
diff --git a/src/reduce.js b/src/reduce.js
index 57da37c26..51f86aab9 100644
--- a/src/reduce.js
+++ b/src/reduce.js
@@ -110,7 +110,14 @@ ReductionPromiseArray.prototype._iterate = function (values) {
                 length: length,
                 array: this
             };
+
             value = value._then(gotAccum, undefined, undefined, ctx, undefined);
+
+            // Too many promises chained with asyncGuaranteed will result in
+            // stack overflow. Break up long chains to reset stack.
+            if ((i & 127) === 0) {
+                value._setNoAsyncGuarantee();
+            }
         }
     }