Update composer and minor fixes to empty ref handling

composer.lock

@@ -248,12 +248,12 @@
             "source": {
                 "type": "git",
                 "url": "https://github.com/composer/composer.git",
-                "reference": "ba1e5c213c2932093ee3d8aa3ee1591ffa35e877"
+                "reference": "9d139cb694b0f08a4ba535395c16a00b2968ac7b"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/composer/composer/zipball/ba1e5c213c2932093ee3d8aa3ee1591ffa35e877",
-                "reference": "ba1e5c213c2932093ee3d8aa3ee1591ffa35e877",
+                "url": "https://api.github.com/repos/composer/composer/zipball/9d139cb694b0f08a4ba535395c16a00b2968ac7b",
+                "reference": "9d139cb694b0f08a4ba535395c16a00b2968ac7b",
                 "shasum": ""
             },
             "require": {
@@ -320,7 +320,7 @@
                 "dependency",
                 "package"
             ],
-            "time": "2019-02-27T14:07:33+00:00"
+            "time": "2019-03-04T07:53:46+00:00"
         },
         {
             "name": "composer/semver",

src/Packagist/WebBundle/Command/RunWorkersCommand.php

@@ -39,6 +39,7 @@ class RunWorkersCommand extends Command
         \Monolog\ErrorHandler::register($this->logger);
 
         $lock = new LockHandler('packagist_run_' . $input->getOption('worker-id'));
+        ini_set('memory_limit', '1G');
 
         // another dumper is still active
         if (!$lock->lock()) {

src/Packagist/WebBundle/Model/PackageManager.php

@@ -65,13 +65,21 @@ class PackageManager
             }
         }
 
+        $em = $this->doctrine->getManager();
+
         $downloadRepo = $this->doctrine->getRepository('PackagistWebBundle:Download');
         $downloadRepo->deletePackageDownloads($package);
 
+        $emptyRefRepo = $this->doctrine->getRepository('PackagistWebBundle:EmptyReferenceCache');
+        $emptyRef = $emptyRefRepo->findOneBy(['package' => $package]);
+        if ($emptyRef) {
+            $em->remove($emptyRef);
+            $em->flush();
+        }
+
         $this->providerManager->deletePackage($package);
         $packageName = $package->getName();
 
-        $em = $this->doctrine->getManager();
         $em->remove($package);
         $em->flush();