Allow derived enum keys

src/Parser/Schema/Reader.php

@@ -162,7 +162,7 @@ private function enumKeys(array $data, string $location, array $enum): array
         }
 
         $keys = Value::stringList($data['x-enum-keys'], "{$location}/x-enum-keys");
-        if (count($keys) !== count($enum)) {
+        if ($keys !== [] && count($keys) !== count($enum)) {
             throw new InvalidSpecification("Expected x-enum-keys to match enum length at {$location}");
         }
 

tests/Schema/ReaderTest.php

@@ -143,6 +143,18 @@ public function test_enum_metadata_is_preserved_for_openapi_two_inline_parameter
         self::assertSame(['NetworkRequests'], $schema->enumKeys);
     }
 
+    public function test_empty_enum_keys_use_derived_names(): void
+    {
+        $schema = $this->reader(Version::V3_0)->read([
+            'type' => 'string',
+            'enum' => ['first', 'second'],
+            'x-enum-keys' => [],
+        ], '#/x');
+
+        self::assertInstanceOf(StringSchema::class, $schema);
+        self::assertSame([], $schema->enumKeys);
+    }
+
     public function test_enum_keys_must_match_enum_length(): void
     {
         $this->expectException(InvalidSpecification::class);