diff --git a/src/Composer/EventDispatcher/EventDispatcher.php b/src/Composer/EventDispatcher/EventDispatcher.php
index 118c75f5b8e0..73b8c58f265d 100644
--- a/src/Composer/EventDispatcher/EventDispatcher.php
+++ b/src/Composer/EventDispatcher/EventDispatcher.php
@@ -576,7 +576,7 @@ private function ensureBinDirIsInPath(): void
         $binDir = $this->composer->getConfig()->get('bin-dir');
         if (is_dir($binDir)) {
             $binDir = realpath($binDir);
-            $pathValue = Platform::getEnv($pathEnv);
+            $pathValue = (string) Platform::getEnv($pathEnv);
             if (!Preg::isMatch('{(^|'.PATH_SEPARATOR.')'.preg_quote($binDir).'($|'.PATH_SEPARATOR.')}', $pathValue)) {
                 Platform::putEnv($pathEnv, $binDir.PATH_SEPARATOR.$pathValue);
             }