Add support for defining a {"packagist.org":false} repo in composer init, fixes #8210

src/Composer/Command/InitCommand.php

@@ -168,13 +168,25 @@ EOT
         if ($repositories) {
             $config = Factory::createConfig($io);
             $repos = array(new PlatformRepository);
+            $createDefaultPackagistRepo = true;
             foreach ($repositories as $repo) {
-                $repos[] = RepositoryFactory::fromString($io, $config, $repo);
+                $repoConfig = RepositoryFactory::configFromString($io, $config, $repo);
+                if (
+                    (isset($repoConfig['packagist']) && $repoConfig === array('packagist' => false))
+                    || (isset($repoConfig['packagist.org']) && $repoConfig === array('packagist.org' => false))
+                ) {
+                    $createDefaultPackagistRepo = false;
+                    continue;
+                }
+                $repos[] = RepositoryFactory::createRepo($io, $config, $repoConfig);
+            }
+
+            if ($createDefaultPackagistRepo) {
+                $repos[] = RepositoryFactory::createRepo($io, $config, array(
+                    'type' => 'composer',
+                    'url' => 'https://repo.packagist.org',
+                ));
             }
-            $repos[] = RepositoryFactory::createRepo($io, $config, array(
-                'type' => 'composer',
-                'url' => 'https://repo.packagist.org',
-            ));
 
             $this->repos = new CompositeRepository($repos);
             unset($repos, $config, $repositories);