diff --git a/src/Composer/Autoload/ClassMapGenerator.php b/src/Composer/Autoload/ClassMapGenerator.php
index 9a8381224..cb948945f 100644
--- a/src/Composer/Autoload/ClassMapGenerator.php
+++ b/src/Composer/Autoload/ClassMapGenerator.php
@@ -272,7 +272,7 @@ class ClassMapGenerator
                 if ($name[0] === ':') {
                     // This is an XHP class, https://github.com/facebook/xhp
                     $name = 'xhp'.substr(str_replace(array('-', ':'), array('_', '__'), $name), 1);
-                } elseif ($matches['type'][$i] === 'enum') {
+                } elseif (strtolower($matches['type'][$i]) === 'enum') {
                     // something like:
                     //   enum Foo: int { HERP = '123'; }
                     // The regex above captures the colon, which isn't part of
diff --git a/src/Composer/Plugin/PluginManager.php b/src/Composer/Plugin/PluginManager.php
index 1e0181a73..b1068b090 100644
--- a/src/Composer/Plugin/PluginManager.php
+++ b/src/Composer/Plugin/PluginManager.php
@@ -656,7 +656,7 @@ class PluginManager
         }
 
         if (false === $allowPluginsConfig) {
-            return array('{^$}D' => false);
+            return array('{}' => false);
         }
 
         $rules = array();
diff --git a/src/Composer/Repository/ComposerRepository.php b/src/Composer/Repository/ComposerRepository.php
index add7d9a6c..34c8dd2a4 100644
--- a/src/Composer/Repository/ComposerRepository.php
+++ b/src/Composer/Repository/ComposerRepository.php
@@ -652,7 +652,7 @@ class ComposerRepository extends ArrayRepository implements ConfigurableReposito
             return array();
         }
 
-        if ($this->providersUrl) {
+        if (null !== $this->providersUrl && null !== $this->providerListing) {
             return array_keys($this->providerListing);
         }
 
diff --git a/tests/Composer/Test/Autoload/Fixtures/php8.1/enum_backed.php b/tests/Composer/Test/Autoload/Fixtures/php8.1/enum_backed.php
index bab09e31b..3954c43e8 100644
--- a/tests/Composer/Test/Autoload/Fixtures/php8.1/enum_backed.php
+++ b/tests/Composer/Test/Autoload/Fixtures/php8.1/enum_backed.php
@@ -1,6 +1,6 @@
 <?php
 
-enum RolesBackedEnum:string {
+EnUm RolesBackedEnum:string {
     case Admin = 'Administrator';
     case Guest = 'Guest';
     case Moderator = 'Moderator';
diff --git a/tests/Composer/Test/ConfigTest.php b/tests/Composer/Test/ConfigTest.php
index de00785a2..fc829c159 100644
--- a/tests/Composer/Test/ConfigTest.php
+++ b/tests/Composer/Test/ConfigTest.php
@@ -328,16 +328,20 @@ class ConfigTest extends TestCase
     {
         Platform::putEnv('COMPOSER_PROCESS_TIMEOUT', '0');
         $config = new Config(true);
-        $this->assertEquals(0, $config->get('process-timeout'));
+        $result = $config->get('process-timeout');
         Platform::clearEnv('COMPOSER_PROCESS_TIMEOUT');
+
+        $this->assertEquals(0, $result);
     }
 
     public function testHtaccessProtect()
     {
         Platform::putEnv('COMPOSER_HTACCESS_PROTECT', '0');
         $config = new Config(true);
-        $this->assertEquals(0, $config->get('htaccess-protect'));
+        $result = $config->get('htaccess-protect');
         Platform::clearEnv('COMPOSER_HTACCESS_PROTECT');
+
+        $this->assertEquals(0, $result);
     }
 
     public function testGetSourceOfValue()
@@ -360,7 +364,9 @@ class ConfigTest extends TestCase
     {
         Platform::putEnv('COMPOSER_HTACCESS_PROTECT', '0');
         $config = new Config;
-        $this->assertEquals('COMPOSER_HTACCESS_PROTECT', $config->getSourceOfValue('htaccess-protect'));
+        $result = $config->getSourceOfValue('htaccess-protect');
         Platform::clearEnv('COMPOSER_HTACCESS_PROTECT');
+
+        $this->assertEquals('COMPOSER_HTACCESS_PROTECT', $result);
     }
 }