diff --git a/src/Composer/Installer.php b/src/Composer/Installer.php
index bf221a125..49e82f06c 100644
--- a/src/Composer/Installer.php
+++ b/src/Composer/Installer.php
@@ -1137,6 +1137,10 @@ class Installer
 
     private function updateInstallReferences(PackageInterface $package, $reference)
     {
+        if (!$reference) {
+            return;
+        }
+
         $package->setSourceReference($reference);
         $package->setDistReference($reference);