diff --git a/lib/cache/index.js b/lib/cache/index.js
index c772bed..5270222 100644
--- a/lib/cache/index.js
+++ b/lib/cache/index.js
@@ -114,11 +114,7 @@ function getStream (byDigest, cache, key, opts) {
   opts = opts || {}
   var stream
   if (!cache || !key) {
-    stream = through()
-    var err = new Error('no cache or key')
-    err.code = 'ENOENT'
-    setImmediate(function () { stream.emit('error', err) })
-    return stream
+    throw new Error('cache and key are required')
   }
   var memoed = MEMOIZED[cache + ':' + key]
   if (memoed) {