Fixes memory leak on anonymous migrations (#46073)

Author: nunomaduro

src/Illuminate/Database/Migrations/Migrator.php

@@ -66,6 +66,13 @@ class Migrator
      */
     protected $paths = [];
 
+    /**
+     * The paths that have already been required.
+     *
+     * @var array<string, \Illuminate\Database\Migrations\Migration|null>
+     */
+    protected static $pathsAlreadyRequired = [];
+
     /**
      * The output interface implementation.
      *
@@ -511,9 +518,13 @@ protected function resolvePath(string $path)
             return new $class;
         }
 
-        $migration = $this->files->getRequire($path);
+        $migration = static::$pathsAlreadyRequired[$path] ??= $this->files->getRequire($path);
 
-        return is_object($migration) ? $migration : new $class;
+        if (is_object($migration)) {
+            return clone $migration;
+        }
+
+        return new $class;
     }
 
     /**