Correct how base options for missing config files are preloaded

Author: u01jmg3

src/Illuminate/Foundation/Bootstrap/LoadConfiguration.php

@@ -5,6 +5,7 @@
 use Illuminate\Config\Repository;
 use Illuminate\Contracts\Config\Repository as RepositoryContract;
 use Illuminate\Contracts\Foundation\Application;
+use Illuminate\Support\Collection;
 use SplFileInfo;
 use Symfony\Component\Finder\Finder;
 
@@ -69,7 +70,7 @@ protected function loadConfigurationFiles(Application $app, RepositoryContract $
             ? $this->getBaseConfiguration()
             : [];
 
-        foreach (array_diff(array_keys($base), array_keys($files)) as $name => $config) {
+        foreach (Collection::make($base)->diffKeys($files) as $name => $config) {
             $repository->set($name, $config);
         }
 

tests/Foundation/Bootstrap/LoadConfigurationTest.php

@@ -2,6 +2,7 @@
 
 namespace Illuminate\Tests\Foundation\Bootstrap;
 
+use Illuminate\Filesystem\Filesystem;
 use Illuminate\Foundation\Application;
 use Illuminate\Foundation\Bootstrap\LoadConfiguration;
 use PHPUnit\Framework\TestCase;
@@ -37,4 +38,23 @@ public function testLoadsConfigurationInIsolation()
         $this->assertNull($app['config']['bar.foo']);
         $this->assertSame('bar', $app['config']['custom.foo']);
     }
+
+    public function testConfigurationArrayKeysMatchLoadedFilenames()
+    {
+        $baseConfigPath = __DIR__.'/../../../config';
+        $customConfigPath = __DIR__.'/../fixtures/config';
+
+        $app = new Application();
+        $app->useConfigPath($customConfigPath);
+
+        (new LoadConfiguration)->bootstrap($app);
+
+        $this->assertEqualsCanonicalizing(
+            array_keys($app['config']->all()),
+            collect((new Filesystem)->files([
+                $baseConfigPath,
+                $customConfigPath,
+            ]))->map(fn ($file) => $file->getBaseName('.php'))->unique()->values()->toArray()
+        );
+    }
 }