Use rule sets' real name when registering

It does not make sense to pass name explicitly during registration, because ruleset should identify itself using contract (`RuleSetDescriptionInterface::getName()`).

doc/config.rst

@@ -142,19 +142,19 @@ configure them in your config file.
         ->setLineEnding("\r\n")
     ;
 
-It's possible to register custom rule sets, which makes it easier to reuse custom configuration between multiple projects. If you have prepared rule set, you can register it and then enable it in the rules. Custom rule sets (in this example `\MyNameSpace\MyRuleSetClass`) must implement `\PhpCsFixer\RuleSet\RuleSetDescriptionInterface`.
+It's possible to register custom rule sets, which makes it easier to reuse custom configuration between multiple projects. If you have prepared rule set, you can register it and then enable it in the rules. Custom rule sets (in this example ``\MyNameSpace\MyRuleSetClass``) must implement ``\PhpCsFixer\RuleSet\RuleSetDescriptionInterface``.
 
 .. code-block:: php
 
     <?php
 
     return (new PhpCsFixer\Config())
         ->registerCustomRuleSets([
-            '@MyRuleSet' => MyNameSpace\MyRuleSetClass::class,
+            MyNameSpace\MyRuleSetClass::class, // It identifies itself as '@MyRuleSet'
         ])
         ->setRules([
             '@MyRuleSet' => true,
         ])
     ;
 
-ℹ️ If you use other `\PhpCsFixer\ConfigInterface` implementation than built-in one, you can register custom rule sets using `\PhpCsFixer\RuleSet\RuleSets::registerRuleSet()` just before the configuration. Currently `\PhpCsFixer\Config::registerCustomRuleSets()` is not part of the `ConfigInterface` because it would be a BC-break - it will be added there in the next major version of the Fixer.
+ℹ️ If you use other ``\PhpCsFixer\ConfigInterface`` implementation than built-in one, you can register custom rule sets using ``\PhpCsFixer\RuleSet\RuleSets::registerRuleSet()`` just before the configuration. Currently ``\PhpCsFixer\Config::registerCustomRuleSets()`` is not part of the ``ConfigInterface`` because it would be a BC-break - it will be added there in the next major version of the Fixer.

src/Config.php

@@ -154,16 +154,14 @@ public function registerCustomFixers(iterable $fixers): ConfigInterface
     /**
      * Registers custom rule sets to be used the same way as built-in rule sets.
      *
-     * `$ruleSets` must follow `'@RuleName' => RuleSetDescriptionInterface::class` convention.
-     *
-     * @param array<string, class-string<RuleSetDescriptionInterface>> $ruleSets
+     * @param list<class-string<RuleSetDescriptionInterface>> $ruleSets
      *
      * @todo Introduce it in ConfigInterface in 4.0
      */
     public function registerCustomRuleSets(array $ruleSets): ConfigInterface
     {
-        foreach ($ruleSets as $name => $class) {
-            RuleSets::registerRuleSet($name, $class);
+        foreach ($ruleSets as $class) {
+            RuleSets::registerRuleSet($class);
         }
 
         return $this;

src/RuleSet/RuleSets.php

@@ -27,7 +27,7 @@ final class RuleSets
     /**
      * @var array<string, RuleSetDescriptionInterface>
      */
-    private static $setDefinitions;
+    private static ?array $setDefinitions = null;
 
     /**
      * @return array<string, RuleSetDescriptionInterface>
@@ -76,8 +76,23 @@ public static function getSetDefinition(string $name): RuleSetDescriptionInterfa
     /**
      * @param class-string<RuleSetDescriptionInterface> $class
      */
-    public static function registerRuleSet(string $name, string $class): void
+    public static function registerRuleSet(string $class): void
     {
+        if (!class_exists($class)
+            || !\in_array(RuleSetDescriptionInterface::class, class_implements($class), true)
+        ) {
+            throw new \InvalidArgumentException(
+                sprintf(
+                    'Class "%s" must be an instance of "%s".',
+                    $class,
+                    RuleSetDescriptionInterface::class
+                )
+            );
+        }
+
+        $ruleset = new $class();
+        $name = $ruleset->getName();
+
         if (!RuleSetNameValidator::isValid($name, false)) {
             throw new \InvalidArgumentException('RuleSet name must begin with "@" and a letter (a-z, A-Z), and can contain only letters (a-z, A-Z), numbers, underscores, slashes, colons, dots and hyphens.');
         }
@@ -92,17 +107,7 @@ public static function registerRuleSet(string $name, string $class): void
             throw new \InvalidArgumentException(sprintf('Set "%s" is already defined.', $name));
         }
 
-        if (!\in_array(RuleSetDescriptionInterface::class, class_implements($class), true)) {
-            throw new \InvalidArgumentException(
-                sprintf(
-                    'Class "%s" must be an instance of "%s".',
-                    $class,
-                    RuleSetDescriptionInterface::class
-                )
-            );
-        }
-
-        self::$setDefinitions[$name] = new $class();
+        self::$setDefinitions[$name] = $ruleset;
 
         self::sortSetDefinitions();
     }

tests/ConfigTest.php

@@ -23,6 +23,7 @@
 use PhpCsFixer\Fixer\ArrayNotation\NoWhitespaceBeforeCommaInArrayFixer;
 use PhpCsFixer\Fixer\ControlStructure\IncludeFixer;
 use PhpCsFixer\Fixer\FixerInterface;
+use PhpCsFixer\RuleSet\RuleSetDescriptionInterface;
 use PhpCsFixer\RuleSet\RuleSets;
 use PhpCsFixer\Tests\Fixtures\ExternalRuleSet\SampleRulesBad;
 use PhpCsFixer\Tests\Fixtures\ExternalRuleSet\SampleRulesOk;
@@ -210,7 +211,7 @@ public function testRegisterCustomFixers(array $expected, iterable $suite): void
     }
 
     /**
-     * @param array<string, string> $ruleSets
+     * @param list<class-string> $ruleSets
      *
      * @dataProvider provideRegisterCustomRuleSetsCases
      */
@@ -224,7 +225,12 @@ public function testRegisterCustomRuleSets(?string $expectedException, array $ru
         $config->registerCustomRuleSets($ruleSets);
 
         if (null === $expectedException) {
-            self::assertContains(array_keys($ruleSets)[0], RuleSets::getSetDefinitionNames());
+            foreach ($ruleSets as $ruleSetClass) {
+                /** @var RuleSetDescriptionInterface $ruleSet */
+                $ruleSet = new $ruleSetClass();
+
+                self::assertContains($ruleSet->getName(), RuleSets::getSetDefinitionNames());
+            }
         }
     }
 
@@ -283,13 +289,13 @@ public static function provideRegisterCustomFixersCases(): iterable
     }
 
     /**
-     * @return iterable<array{0: null|class-string<\Throwable>, 1: array<string, class-string>}>
+     * @return iterable<array{0: null|class-string<\Throwable>, 1: list<class-string>}>
      */
     public static function provideRegisterCustomRuleSetsCases(): iterable
     {
-        yield [null, ['@RulesOk' => SampleRulesOk::class]];
+        yield [null, [SampleRulesOk::class]];
 
-        yield [\InvalidArgumentException::class, ['@RulesBad' => SampleRulesBad::class]];
+        yield [\InvalidArgumentException::class, [SampleRulesBad::class]];
     }
 
     public function testConfigConstructorWithName(): void

tests/RuleSet/RuleSetsTest.php

@@ -33,6 +33,17 @@
  */
 final class RuleSetsTest extends TestCase
 {
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        // Since we register custom rule sets statically, we need to clear resolved rule sets between runs.
+        $reflection = new \ReflectionClass(RuleSets::class);
+        $reflectionProperty = $reflection->getProperty('setDefinitions');
+        $reflectionProperty->setAccessible(true);
+        $reflectionProperty->setValue($reflection, null);
+    }
+
     public function testGetSetDefinitionNames(): void
     {
         self::assertSame(
@@ -177,33 +188,27 @@ public function testRegisterRuleSetMissingClass(): void
     {
         self::expectException(\InvalidArgumentException::class);
         // @phpstan-ignore-next-line
-        RuleSets::registerRuleSet('@Vendor/MyRules', '\This\Class\Does\Not\Exists');
+        RuleSets::registerRuleSet('\This\Class\Does\Not\Exists');
     }
 
     public function testRegisterRuleSetOverlappingName(): void
     {
-        RuleSets::registerRuleSet('@Vendor/MyAnotherRuleSetForTesting', SampleRulesOk::class);
-        self::expectException(\InvalidArgumentException::class);
-        RuleSets::registerRuleSet('@Vendor/MyAnotherRuleSetForTesting', SampleRulesOk::class);
-    }
-
-    public function testRegisterRuleSetInvalidName(): void
-    {
+        RuleSets::registerRuleSet(SampleRulesOk::class);
         self::expectException(\InvalidArgumentException::class);
-        RuleSets::registerRuleSet('bad name', SampleRulesOk::class);
+        RuleSets::registerRuleSet(SampleRulesOk::class);
     }
 
     public function testRegisterRuleSetInvalidClass(): void
     {
         self::expectException(\InvalidArgumentException::class);
-        // @phpstan-ignore-next-line
-        RuleSets::registerRuleSet('@Vendor/MyClass', SampleRulesBad::class);
+
+        RuleSets::registerRuleSet(SampleRulesBad::class); // @phpstan-ignore-line
     }
 
     public function testCanReadCustomRegisteredRuleSet(): void
     {
-        RuleSets::registerRuleSet('@Vendor/MySet', SampleRulesOk::class);
-        $set = RuleSets::getSetDefinition('@Vendor/MySet');
+        RuleSets::registerRuleSet(SampleRulesOk::class);
+        $set = RuleSets::getSetDefinition('@Vendor/RulesOk');
         self::assertSame('@Vendor/RulesOk', $set->getName());
     }