From 786aed49ddd646d87a08cd24477efa791e93f538 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Sun, 6 Mar 2016 02:15:56 -0800
Subject: [PATCH] throw if async callback is executed twice.

---
 lib/bcoin/utils.js | 42 +++++++++++++++++++++++++++++++++---------
 1 file changed, 33 insertions(+), 9 deletions(-)

diff --git a/lib/bcoin/utils.js b/lib/bcoin/utils.js
index 81ebc8e8..03d2ebe9 100644
--- a/lib/bcoin/utils.js
+++ b/lib/bcoin/utils.js
@@ -1426,8 +1426,8 @@ utils.ccmp = function(a, b) {
   var res = 0;
   var i;
 
-  assert(Buffer.isBuffer(a));
-  assert(Buffer.isBuffer(b));
+  utils.assert(Buffer.isBuffer(a));
+  utils.assert(Buffer.isBuffer(b));
 
   if (a.length !== b.length)
     return false;
@@ -1448,6 +1448,7 @@ utils.forRange = function forRange(from, to, iter, callback) {
     return callback();
 
   function next(err) {
+    utils.assert(pending > 0);
     if (err)
       error = err;
     if (!--pending)
@@ -1468,6 +1469,7 @@ utils.forEach = function forEach(arr, iter, callback) {
     return callback();
 
   function next(err) {
+    utils.assert(pending > 0);
     if (err)
       error = err;
     if (!--pending)
@@ -1480,13 +1482,20 @@ utils.forEach = function forEach(arr, iter, callback) {
 };
 
 utils.forRangeSerial = function forRangeSerial(from, to, iter, callback) {
+  var called = false;
+
   callback = utils.asyncify(callback);
 
   (function next(err) {
-    if (err)
+    utils.assert(!called);
+    if (err) {
+      called = true;
       return callback(err);
-    if (from >= to)
+    }
+    if (from >= to) {
+      called = true;
       return callback();
+    }
     from++;
     utils.nextTick(function() {
       iter(from - 1, next, from - 1);
@@ -1496,15 +1505,21 @@ utils.forRangeSerial = function forRangeSerial(from, to, iter, callback) {
 
 utils.forEachSerial = function forEachSerial(arr, iter, callback) {
   var i = 0;
+  var called = false;
 
   callback = utils.asyncify(callback);
 
   (function next(err) {
     var item;
-    if (err)
+    utils.assert(!called);
+    if (err) {
+      called = true;
       return callback(err);
-    if (i >= arr.length)
+    }
+    if (i >= arr.length) {
+      called = true;
       return callback();
+    }
     item = arr[i];
     i++;
     utils.nextTick(function() {
@@ -1524,6 +1539,7 @@ utils.every = function every(arr, iter, callback) {
     return callback(null, result);
 
   function next(err, res) {
+    utils.assert(pending > 0);
     if (err)
       error = err;
     if (!res)
@@ -1542,17 +1558,25 @@ utils.every = function every(arr, iter, callback) {
 
 utils.everySerial = function everySerial(arr, iter, callback) {
   var i = 0;
+  var called = false;
 
   callback = utils.asyncify(callback);
 
   (function next(err, res) {
     var item;
-    if (err)
+    utils.assert(!called);
+    if (err) {
+      called = true;
       return callback(err);
-    if (!result)
+    }
+    if (!result) {
+      called = true;
       return callback(null, false);
-    if (i >= arr.length)
+    }
+    if (i >= arr.length) {
+      called = true;
       return callback(null, true);
+    }
     item = arr[i];
     i++;
     utils.nextTick(function() {