diff --git a/src/Composer/Package/Loader/ArrayLoader.php b/src/Composer/Package/Loader/ArrayLoader.php
index 72e0df76a..47b314e33 100644
--- a/src/Composer/Package/Loader/ArrayLoader.php
+++ b/src/Composer/Package/Loader/ArrayLoader.php
@@ -271,7 +271,7 @@ class ArrayLoader implements LoaderInterface
             }
 
             if (!empty($config['keywords']) && \is_array($config['keywords'])) {
-                $package->setKeywords($config['keywords']);
+                $package->setKeywords(array_map('strval', $config['keywords']));
             }
 
             if (!empty($config['license'])) {
diff --git a/src/Composer/Package/Loader/ValidatingArrayLoader.php b/src/Composer/Package/Loader/ValidatingArrayLoader.php
index 1bcd294b5..2977091fc 100644
--- a/src/Composer/Package/Loader/ValidatingArrayLoader.php
+++ b/src/Composer/Package/Loader/ValidatingArrayLoader.php
@@ -571,7 +571,7 @@ class ValidatingArrayLoader implements LoaderInterface
                 continue;
             }
 
-            if ($regex && !Preg::isMatch('{^'.$regex.'$}u', $value)) {
+            if ($regex && !Preg::isMatch('{^'.$regex.'$}u', (string) $value)) {
                 $this->warnings[] = $property.'.'.$key.' : invalid value ('.$value.'), must match '.$regex;
                 unset($this->config[$property][$key]);
                 $pass = false;