Merge pull request #7212 from theofidry/bugfix/fix-null-io

Allow Composer to be used without running the application

src/Composer/Console/Application.php

@@ -12,6 +12,7 @@
 
 namespace Composer\Console;
 
+use Composer\IO\NullIO;
 use Composer\Util\Platform;
 use Composer\Util\Silencer;
 use Symfony\Component\Console\Application as BaseApplication;
@@ -85,6 +86,8 @@ class Application extends BaseApplication
             });
         }
 
+        $this->io = new NullIO();
+
         parent::__construct('Composer', Composer::VERSION);
     }