Fixes caolan/async#263 and other dependency issues by detecting dead-locks and throwing an Error.

1 files changed, 11 insertions, 0 deletions

diff --git a/lib/async.js b/lib/async.js
index a13f835..50f7a28 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));