Fix errors during the upgrade or downgrade of symfony/flex

Author: rosier

src/Command/GenerateIdCommand.php

@@ -18,6 +18,13 @@
 
 class GenerateIdCommand extends Command
 {
+    public function __construct(/* cannot be type-hinted */ $flex = null)
+    {
+        // No-op to support downgrading to v1.12.x
+
+        parent::__construct();
+    }
+
     protected function configure()
     {
         $this->setName('symfony:generate-id');

src/Downloader.php

@@ -59,6 +59,11 @@ public function getSessionId(): string
         return $this->sess;
     }
 
+    public function setFlexId(string $id = null)
+    {
+        // No-op to support downgrading to v1.12.x
+    }
+
     public function isEnabled()
     {
         return $this->enabled;

src/Flex.php

@@ -275,7 +275,9 @@ class_exists(__NAMESPACE__.str_replace('/', '\\', substr($file, \strlen(__DIR__)
             $app->add(new Command\UnpackCommand($resolver));
             $app->add(new Command\RecipesCommand($this, $this->lock, $rfs));
             $app->add(new Command\InstallRecipesCommand($this, $this->options->get('root-dir')));
-            $app->add(new Command\GenerateIdCommand());
+            if (class_exists(Command\GenerateIdCommand::class)) {
+                $app->add(new Command\GenerateIdCommand(null));
+            }
             $app->add(new Command\DumpEnvCommand($this->config, $this->options));
 
             break;