diff --git a/src/Composer/Package/Package.php b/src/Composer/Package/Package.php
index 300c5ef03..1f1cdf553 100644
--- a/src/Composer/Package/Package.php
+++ b/src/Composer/Package/Package.php
@@ -594,7 +594,10 @@ class Package extends BasePackage
 
         // only bitbucket, github and gitlab have auto generated dist URLs that easily allow replacing the reference in the dist URL
         // TODO generalize this a bit for self-managed/on-prem versions? Some kind of replace token in dist urls which allow this?
-        if (preg_match('{^https?://(?:(?:www\.)?bitbucket\.org|(api\.)?github\.com|(?:www\.)?gitlab\.com)/}i', $this->getDistUrl())) {
+        if (
+            $this->getDistUrl() !== null
+            && preg_match('{^https?://(?:(?:www\.)?bitbucket\.org|(api\.)?github\.com|(?:www\.)?gitlab\.com)/}i', $this->getDistUrl())
+        ) {
             $this->setDistReference($reference);
             $this->setDistUrl(preg_replace('{(?<=/|sha=)[a-f0-9]{40}(?=/|$)}i', $reference, $this->getDistUrl()));
         } elseif ($this->getDistReference()) { // update the dist reference if there was one, but if none was provided ignore it