Trigger the standard autoloader as the last resort

lib/Doctrine/Common/Annotations/AnnotationRegistry.php

@@ -47,22 +47,30 @@ final class AnnotationRegistry
      */
     static private $failedToAutoload = [];
 
+    /**
+     * Whenever registerFile() was used. Disables use of standard autoloader.
+     *
+     * @var bool
+     */
+    static private $registerFileUsed = false;
+
     public static function reset() : void
     {
         self::$autoloadNamespaces = [];
         self::$loaders            = [];
         self::$failedToAutoload   = [];
+        self::$registerFileUsed   = false;
     }
 
     /**
      * Registers file.
      *
-     * @deprecated this method is deprecated and will be removed in doctrine/annotations 2.0
-     *             autoloading should be deferred to the globally registered autoloader by then. For now,
-     *             use @example AnnotationRegistry::registerLoader('class_exists')
+     * @deprecated This method is deprecated and will be removed in doctrine/annotations 2.0. Annotations will be autoloaded in 2.0.
      */
     public static function registerFile(string $file) : void
     {
+        self::$registerFileUsed = true;
+
         require_once $file;
     }
 
@@ -74,9 +82,7 @@ public static function registerFile(string $file) : void
      * @param string            $namespace
      * @param string|array|null $dirs
      *
-     * @deprecated this method is deprecated and will be removed in doctrine/annotations 2.0
-     *             autoloading should be deferred to the globally registered autoloader by then. For now,
-     *             use @example AnnotationRegistry::registerLoader('class_exists')
+     * @deprecated This method is deprecated and will be removed in doctrine/annotations 2.0. Annotations will be autoloaded in 2.0.
      */
     public static function registerAutoloadNamespace(string $namespace, $dirs = null) : void
     {
@@ -90,9 +96,7 @@ public static function registerAutoloadNamespace(string $namespace, $dirs = null
      *
      * @param string[][]|string[]|null[] $namespaces indexed by namespace name
      *
-     * @deprecated this method is deprecated and will be removed in doctrine/annotations 2.0
-     *             autoloading should be deferred to the globally registered autoloader by then. For now,
-     *             use @example AnnotationRegistry::registerLoader('class_exists')
+     * @deprecated This method is deprecated and will be removed in doctrine/annotations 2.0. Annotations will be autoloaded in 2.0.
      */
     public static function registerAutoloadNamespaces(array $namespaces) : void
     {
@@ -105,9 +109,7 @@ public static function registerAutoloadNamespaces(array $namespaces) : void
      * NOTE: These class loaders HAVE to be silent when a class was not found!
      * IMPORTANT: Loaders have to return true if they loaded a class that could contain the searched annotation class.
      *
-     * @deprecated this method is deprecated and will be removed in doctrine/annotations 2.0
-     *             autoloading should be deferred to the globally registered autoloader by then. For now,
-     *             use @example AnnotationRegistry::registerLoader('class_exists')
+     * @deprecated This method is deprecated and will be removed in doctrine/annotations 2.0. Annotations will be autoloaded in 2.0.
      */
     public static function registerLoader(callable $callable) : void
     {
@@ -119,7 +121,7 @@ public static function registerLoader(callable $callable) : void
     /**
      * Registers an autoloading callable for annotations, if it is not already registered
      *
-     * @deprecated this method is deprecated and will be removed in doctrine/annotations 2.0
+     * @deprecated This method is deprecated and will be removed in doctrine/annotations 2.0. Annotations will be autoloaded in 2.0.
      */
     public static function registerUniqueLoader(callable $callable) : void
     {
@@ -167,6 +169,10 @@ public static function loadAnnotationClass(string $class) : bool
             }
         }
 
+        if (self::$loaders === [] && self::$autoloadNamespaces === [] && self::$registerFileUsed === false && \class_exists($class)) {
+            return true;
+        }
+
         self::$failedToAutoload[$class] = null;
 
         return false;

tests/Doctrine/Tests/Common/Annotations/AnnotationRegistryTest.php

@@ -3,6 +3,9 @@
 namespace Doctrine\Tests\Common\Annotations;
 
 use Doctrine\Common\Annotations\AnnotationRegistry;
+use Doctrine\Tests\Common\Annotations\Fixtures\Annotation\CanBeAutoLoaded;
+use Doctrine\Tests\Common\Annotations\Fixtures\Annotation\LoadedUsingRegisterFile;
+use Doctrine\Tests\Common\Annotations\Fixtures\Annotation\ShouldNeverBeLoaded;
 use PHPUnit\Framework\TestCase;
 
 class AnnotationRegistryTest extends TestCase
@@ -183,4 +186,26 @@ public function testRegisterLoaderIfNotExistsOnlyRegisteresSameLoaderOnce() : vo
         AnnotationRegistry::loadAnnotationClass($className);
         AnnotationRegistry::loadAnnotationClass($className);
     }
+
+    /**
+     * @runInSeparateProcess
+     */
+    public function testClassExistsFallback() : void
+    {
+        AnnotationRegistry::reset();
+
+        self::assertTrue(AnnotationRegistry::loadAnnotationClass(CanBeAutoLoaded::class));
+    }
+
+    /**
+     * @runInSeparateProcess
+     */
+    public function testClassExistsFallbackNotUsedWhenRegisterFileUsed() : void
+    {
+        AnnotationRegistry::reset();
+        AnnotationRegistry::registerFile(__DIR__ . '/Fixtures/Annotation/LoadedUsingRegisterFile.php');
+
+        self::assertTrue(AnnotationRegistry::loadAnnotationClass(LoadedUsingRegisterFile::class));
+        self::assertFalse(AnnotationRegistry::loadAnnotationClass(ShouldNeverBeLoaded::class));
+    }
 }

tests/Doctrine/Tests/Common/Annotations/Fixtures/Annotation/CanBeAutoLoaded.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace Doctrine\Tests\Common\Annotations\Fixtures\Annotation;
+
+/** @Annotation */
+class CanBeAutoLoaded
+{
+}

tests/Doctrine/Tests/Common/Annotations/Fixtures/Annotation/LoadedUsingRegisterFile.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace Doctrine\Tests\Common\Annotations\Fixtures\Annotation;
+
+/** @Annotation */
+class LoadedUsingRegisterFile
+{
+}

tests/Doctrine/Tests/Common/Annotations/Fixtures/Annotation/ShouldNeverBeLoaded.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace Doctrine\Tests\Common\Annotations\Fixtures\Annotation;
+
+/** @Annotation */
+class ShouldNeverBeLoaded
+{
+}