diff --git a/src/Composer/Autoload/ClassLoader.php b/src/Composer/Autoload/ClassLoader.php
index 95106127c..1a58957d2 100644
--- a/src/Composer/Autoload/ClassLoader.php
+++ b/src/Composer/Autoload/ClassLoader.php
@@ -60,7 +60,7 @@ class ClassLoader
     public function getPrefixes()
     {
         if (!empty($this->prefixesPsr0)) {
-            return call_user_func_array('array_merge', $this->prefixesPsr0);
+            return call_user_func_array('array_merge', array_values($this->prefixesPsr0));
         }
 
         return array();
diff --git a/src/Composer/Repository/ComposerRepository.php b/src/Composer/Repository/ComposerRepository.php
index 34e5e85df..06061ed64 100644
--- a/src/Composer/Repository/ComposerRepository.php
+++ b/src/Composer/Repository/ComposerRepository.php
@@ -993,7 +993,7 @@ class ComposerRepository extends ArrayRepository implements ConfigurableReposito
 
         if (isset($data['includes'])) {
             foreach ($data['includes'] as $include => $metadata) {
-                if ($this->cache->sha1($include) === $metadata['sha1']) {
+                if (isset($metadata['sha1']) && $this->cache->sha1($include) === $metadata['sha1']) {
                     $includedData = json_decode($this->cache->read($include), true);
                 } else {
                     $includedData = $this->fetchFile($include);