Re-introduce nonexistent dependency check

1 files changed, 5 insertions, 0 deletions

diff --git a/lib/auto.js b/lib/auto.js
index 925db77..c36bb8f 100644
--- a/lib/auto.js
+++ b/lib/auto.js
@@ -134,6 +134,11 @@ export default function (tasks, concurrency, callback) {
         uncheckedDependencies[key] = remainingDependencies;
 
         arrayEach(dependencies, function (dependencyName) {
+            if (!tasks[dependencyName]) {
+                throw new Error('async.auto task `' + key +
+                    '` has a non-existent dependency in ' +
+                    dependencies.join(', '));
+            }
             addListener(dependencyName, function () {
                 remainingDependencies--;
                 if (remainingDependencies === 0) {