diff --git a/src/Composer/Util/GitHub.php b/src/Composer/Util/GitHub.php
index 2dd53e350..84ca062fe 100644
--- a/src/Composer/Util/GitHub.php
+++ b/src/Composer/Util/GitHub.php
@@ -101,9 +101,9 @@ class GitHub
         $this->io->writeError(sprintf('Tokens will be stored in plain text in "%s" for future use by Composer.', $this->config->getAuthConfigSource()->getName()));
         $this->io->writeError('For additional information, check https://getcomposer.org/doc/articles/authentication-for-private-packages.md#github-oauth');
 
-        $token = trim($this->io->askAndHideAnswer('Token (hidden): '));
+        $token = trim((string) $this->io->askAndHideAnswer('Token (hidden): '));
 
-        if (!$token) {
+        if ($token === '') {
             $this->io->writeError('<warning>No token given, aborting.</warning>');
             $this->io->writeError('You can also add it manually later by using "composer config --global --auth github-oauth.github.com <token>"');