Fix regression in global command, fixes #5266

src/Composer/Command/GlobalCommand.php

@@ -76,6 +76,7 @@ EOT
 
         // create new input without "global" command prefix
         $input = new StringInput(preg_replace('{\bg(?:l(?:o(?:b(?:a(?:l)?)?)?)?)?\b}', '', $input->__toString(), 1));
+        $this->getApplication()->resetComposer();
 
         return $this->getApplication()->run($input, $output);
     }

src/Composer/Console/Application.php

@@ -116,7 +116,9 @@ class Application extends BaseApplication
             }
         }
 
-        if ($commandName !== 'global' && $commandName !== 'outdated') {
+        $isProxyCommand = $commandName === 'global' || $commandName === 'outdated';
+
+        if (!$isProxyCommand) {
             $io->writeError(sprintf(
                 'Running %s (%s) with %s on %s',
                 Composer::VERSION,
@@ -194,7 +196,7 @@ class Application extends BaseApplication
                 $this->io->enableDebugging($startTime);
             }
 
-            if (!$input->hasParameterOption('--no-plugins')) {
+            if (!$input->hasParameterOption('--no-plugins') && !$isProxyCommand) {
                 foreach ($this->getPluginCommands() as $command) {
                     if ($this->has($command->getName())) {
                         $io->writeError('<warning>Plugin command '.$command->getName().' ('.get_class($command).') would override a Composer command and has been skipped</warning>');