diff --git a/lib/manager/composer/artifacts.ts b/lib/manager/composer/artifacts.ts
index 7a4aaecde405344ae7a93a7797bc633a6b7feb87..1b1ad2286f9636068109c192210d1cd625a666f3 100644
--- a/lib/manager/composer/artifacts.ts
+++ b/lib/manager/composer/artifacts.ts
@@ -16,7 +16,6 @@ import {
   ensureDir,
   ensureLocalDir,
   getSiblingFileName,
-  getSubDirectory,
   readLocalFile,
   writeLocalFile,
 } from '../../util/fs';