Run Composer\Package\Locker::fixupJsonDataType on lock data

README.md

@@ -2475,15 +2475,13 @@ None - this is a Composer's plugin, it will subscribe to Composer's events itsel
      ],
      "aliases": [],
      "minimum-stability": "stable",
--    "stability-flags": {},
-+    "stability-flags": [],
+     "stability-flags": {},
      "prefer-stable": false,
      "prefer-lowest": false,
      "platform": {
          "php": "^7.2.5 || ^8.0"
      },
--    "platform-dev": {},
-+    "platform-dev": [],
+     "platform-dev": {},
      "platform-overrides": {
          "php": "7.2.5"
      },

src/Plugin.php

@@ -15,6 +15,7 @@
 use Composer\EventDispatcher\EventSubscriberInterface;
 use Composer\IO\IOInterface;
 use Composer\Json\JsonFile;
+use Composer\Package\Locker;
 use Composer\Plugin\PluginInterface;
 use Composer\Script\Event;
 use Composer\Script\ScriptEvents;
@@ -67,6 +68,12 @@ public static function clean(Event $event): void
             }
         }
 
+        $composerLockData = \Closure::bind(
+            static fn (Locker $locker) => $locker->fixupJsonDataType($composerLockData),
+            null,
+            Locker::class,
+        )((new \ReflectionClass(Locker::class))->newInstanceWithoutConstructor());
+
         $lock->write($composerLockData);
     }