From 2410077e26d5429ac45533438f008706dcb989f7 Mon Sep 17 00:00:00 2001
From: Mickael van der Beek <mickael@sagacify.com>
Date: Tue, 18 Nov 2014 21:20:56 +0100
Subject: [PATCH 1/2] Fixes caolan/async#263 and other dependency issues by
 detecting dead-locks and throwing an Error.

---
 lib/async.js       | 11 +++++++++++
 test/test-async.js | 27 +++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/lib/async.js b/lib/async.js
index a13f83520..50f7a2806 100755
--- a/lib/async.js
+++ b/lib/async.js
@@ -478,6 +478,17 @@
                 }
             };
             var requires = task.slice(0, Math.abs(task.length - 1)) || [];
+            // prevent dead-locks
+            var len = requires.length;
+            var dep;
+            while (len--) {
+                if (!(dep = tasks[requires[len]])) {
+                    throw new Error('Has inexistant dependency');
+                }
+                if (_isArray(dep) && !!~dep.indexOf(k)) {
+                    throw new Error('Has cyclic dependencies');
+                }
+            }
             var ready = function () {
                 return _reduce(requires, function (a, x) {
                     return (a && results.hasOwnProperty(x));
diff --git a/test/test-async.js b/test/test-async.js
index 6a3560694..8ee2bd903 100755
--- a/test/test-async.js
+++ b/test/test-async.js
@@ -580,6 +580,33 @@ exports['auto modifying results causes final callback to run early'] = function(
     });
 };
 
+// Issue 263 on github: https://github.com/caolan/async/issues/263
+exports['auto prevent dead-locks due to inexistant dependencies'] = function(test) {
+    test.throws(function () {
+        async.auto({
+            task1: ['noexist', function(callback, results){
+                callback(null, 'task1');
+            }]
+        });
+    }, Error);
+    test.done();
+};
+
+// Issue 263 on github: https://github.com/caolan/async/issues/263
+exports['auto prevent dead-locks due to cyclic dependencies'] = function(test) {
+    test.throws(function () {
+        async.auto({
+            task3: ['task4', function(callback, results){
+                callback(null, 'task3');
+            }],
+            task4: ['task3', function(callback, results){
+                callback(null, 'task4');
+            }]
+        });
+    }, Error);
+    test.done();
+};
+
 // Issue 306 on github: https://github.com/caolan/async/issues/306
 exports['retry when attempt succeeds'] = function(test) {
     var failed = 3

From 74819d24051d1457c73ab301d697ec8b467115f8 Mon Sep 17 00:00:00 2001
From: Mickael van der Beek <mickael@sagacify.com>
Date: Tue, 18 Nov 2014 21:24:02 +0100
Subject: [PATCH 2/2] Corrected task name typo for consistency with other
 tests.

---
 test/test-async.js | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/test/test-async.js b/test/test-async.js
index 8ee2bd903..a84cb4907 100755
--- a/test/test-async.js
+++ b/test/test-async.js
@@ -596,11 +596,11 @@ exports['auto prevent dead-locks due to inexistant dependencies'] = function(tes
 exports['auto prevent dead-locks due to cyclic dependencies'] = function(test) {
     test.throws(function () {
         async.auto({
-            task3: ['task4', function(callback, results){
-                callback(null, 'task3');
+            task1: ['task2', function(callback, results){
+                callback(null, 'task1');
             }],
-            task4: ['task3', function(callback, results){
-                callback(null, 'task4');
+            task2: ['task1', function(callback, results){
+                callback(null, 'task2');
             }]
         });
     }, Error);