[DI][Contracts] add and implement ServiceProviderInterface

src/Symfony/Component/DependencyInjection/Argument/ServiceLocator.php

@@ -22,11 +22,13 @@ class ServiceLocator extends BaseServiceLocator
 {
     private $factory;
     private $serviceMap;
+    private $serviceTypes;
 
-    public function __construct(\Closure $factory, array $serviceMap)
+    public function __construct(\Closure $factory, array $serviceMap, array $serviceTypes = null)
     {
         $this->factory = $factory;
         $this->serviceMap = $serviceMap;
+        $this->serviceTypes = $serviceTypes;
         parent::__construct($serviceMap);
     }
 
@@ -37,4 +39,12 @@ class ServiceLocator extends BaseServiceLocator
     {
         return isset($this->serviceMap[$id]) ? ($this->factory)(...$this->serviceMap[$id]) : parent::get($id);
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getProvidedServices(): array
+    {
+        return $this->serviceTypes ?? $this->serviceTypes = array_map(function () { return '?'; }, $this->serviceMap);
+    }
 }

src/Symfony/Component/DependencyInjection/CHANGELOG.md

@@ -13,6 +13,7 @@ CHANGELOG
  * added `ReverseContainer`: a container that turns services back to their ids
  * added ability to define an index for a tagged collection
  * added ability to define an index for services in an injected service locator argument
+ * made `ServiceLocator` implement `ServiceProviderInterface`
  * deprecated support for non-string default env() parameters
 
 4.2.0

src/Symfony/Component/DependencyInjection/Compiler/ResolveServiceSubscribersPass.php

@@ -14,6 +14,7 @@ namespace Symfony\Component\DependencyInjection\Compiler;
 use Psr\Container\ContainerInterface;
 use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\Reference;
+use Symfony\Contracts\Service\ServiceProviderInterface;
 
 /**
  * Compiler pass to inject their service locator to service subscribers.
@@ -26,7 +27,7 @@ class ResolveServiceSubscribersPass extends AbstractRecursivePass
 
     protected function processValue($value, $isRoot = false)
     {
-        if ($value instanceof Reference && $this->serviceLocator && ContainerInterface::class === (string) $value) {
+        if ($value instanceof Reference && $this->serviceLocator && \in_array((string) $value, [ContainerInterface::class, ServiceProviderInterface::class], true)) {
             return new Reference($this->serviceLocator);
         }
 

src/Symfony/Component/DependencyInjection/ContainerBuilder.php

@@ -1234,13 +1234,14 @@ class ContainerBuilder extends Container implements TaggedContainerInterface
                 return $count;
             });
         } elseif ($value instanceof ServiceLocatorArgument) {
-            $refs = [];
+            $refs = $types = [];
             foreach ($value->getValues() as $k => $v) {
                 if ($v) {
                     $refs[$k] = [$v];
+                    $types[$k] = $v instanceof TypedReference ? $v->getType() : '?';
                 }
             }
-            $value = new ServiceLocator(\Closure::fromCallable([$this, 'resolveServices']), $refs);
+            $value = new ServiceLocator(\Closure::fromCallable([$this, 'resolveServices']), $refs, $types);
         } elseif ($value instanceof Reference) {
             $value = $this->doGet((string) $value, $value->getInvalidBehavior(), $inlineServices, $isConstructorArgument);
         } elseif ($value instanceof Definition) {

src/Symfony/Component/DependencyInjection/Dumper/PhpDumper.php

@@ -1546,6 +1546,7 @@ EOF;
 
                 if ($value instanceof ServiceLocatorArgument) {
                     $serviceMap = '';
+                    $serviceTypes = '';
                     foreach ($value->getValues() as $k => $v) {
                         if (!$v) {
                             continue;
@@ -1559,11 +1560,12 @@ EOF;
                             $this->export(ContainerInterface::IGNORE_ON_UNINITIALIZED_REFERENCE !== $v->getInvalidBehavior() && !\is_string($load) ? $this->generateMethodName($id).($load ? '.php' : '') : null),
                             $this->export($load)
                         );
+                        $serviceTypes .= sprintf("\n            %s => %s,", $this->export($k), $this->export($v instanceof TypedReference ? $v->getType() : '?'));
                         $this->locatedIds[$id] = true;
                     }
                     $this->addGetService = true;
 
-                    return sprintf('new \%s($this->getService, [%s%s])', ServiceLocator::class, $serviceMap, $serviceMap ? "\n        " : '');
+                    return sprintf('new \%s($this->getService, [%s%s], [%s%s])', ServiceLocator::class, $serviceMap, $serviceMap ? "\n        " : '', $serviceTypes, $serviceTypes ? "\n        " : '');
                 }
             } finally {
                 list($this->definitionVariables, $this->referenceVariables) = $scope;

src/Symfony/Component/DependencyInjection/ServiceLocator.php

@@ -12,19 +12,19 @@
 namespace Symfony\Component\DependencyInjection;
 
 use Psr\Container\ContainerExceptionInterface;
-use Psr\Container\ContainerInterface as PsrContainerInterface;
 use Psr\Container\NotFoundExceptionInterface;
 use Symfony\Component\DependencyInjection\Exception\RuntimeException;
 use Symfony\Component\DependencyInjection\Exception\ServiceCircularReferenceException;
 use Symfony\Component\DependencyInjection\Exception\ServiceNotFoundException;
 use Symfony\Contracts\Service\ServiceLocatorTrait;
+use Symfony\Contracts\Service\ServiceProviderInterface;
 use Symfony\Contracts\Service\ServiceSubscriberInterface;
 
 /**
  * @author Robin Chalas <robin.chalas@gmail.com>
  * @author Nicolas Grekas <p@tchwork.com>
  */
-class ServiceLocator implements PsrContainerInterface
+class ServiceLocator implements ServiceProviderInterface
 {
     use ServiceLocatorTrait {
         get as private doGet;

src/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services_rot13_env.php

@@ -72,6 +72,8 @@ class Symfony_DI_PhpDumper_Test_Rot13Parameters extends Container
     {
         return $this->services['container.env_var_processors_locator'] = new \Symfony\Component\DependencyInjection\Argument\ServiceLocator($this->getService, [
             'rot13' => ['services', 'Symfony\\Component\\DependencyInjection\\Tests\\Dumper\\Rot13EnvVarProcessor', 'getRot13EnvVarProcessorService', false],
+        ], [
+            'rot13' => '?',
         ]);
     }
 

src/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services_service_locator_argument.php

@@ -72,6 +72,12 @@ class Symfony_DI_PhpDumper_Service_Locator_Argument extends Container
             'foo3' => [false, 'foo3', 'getFoo3Service', false],
             'foo4' => ['privates', 'foo4', NULL, 'BOOM'],
             'foo5' => ['services', 'foo5', NULL, false],
+        ], [
+            'foo1' => '?',
+            'foo2' => '?',
+            'foo3' => '?',
+            'foo4' => '?',
+            'foo5' => '?',
         ]);
 
         return $instance;

src/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services_subscriber.php

@@ -75,6 +75,11 @@ class ProjectServiceContainer extends Container
             'Symfony\\Component\\DependencyInjection\\Tests\\Fixtures\\TestServiceSubscriber' => ['services', 'Symfony\\Component\\DependencyInjection\\Tests\\Fixtures\\TestServiceSubscriber', 'getTestServiceSubscriberService', false],
             'bar' => ['services', 'Symfony\\Component\\DependencyInjection\\Tests\\Fixtures\\TestServiceSubscriber', 'getTestServiceSubscriberService', false],
             'baz' => ['privates', 'Symfony\\Component\\DependencyInjection\\Tests\\Fixtures\\CustomDefinition', 'getCustomDefinitionService', false],
+        ], [
+            'Symfony\\Component\\DependencyInjection\\Tests\\Fixtures\\CustomDefinition' => 'Symfony\\Component\\DependencyInjection\\Tests\\Fixtures\\CustomDefinition',
+            'Symfony\\Component\\DependencyInjection\\Tests\\Fixtures\\TestServiceSubscriber' => 'Symfony\\Component\\DependencyInjection\\Tests\\Fixtures\\TestServiceSubscriber',
+            'bar' => 'Symfony\\Component\\DependencyInjection\\Tests\\Fixtures\\CustomDefinition',
+            'baz' => 'Symfony\\Component\\DependencyInjection\\Tests\\Fixtures\\CustomDefinition',
         ]))->withContext('foo_service', $this));
     }
 

src/Symfony/Component/DependencyInjection/Tests/ServiceLocatorTest.php

@@ -86,6 +86,21 @@ class ServiceLocatorTest extends BaseServiceLocatorTest
         $this->assertSame('baz', $locator('bar'));
         $this->assertNull($locator('dummy'), '->__invoke() should return null on invalid service');
     }
+
+    public function testProvidesServicesInformation()
+    {
+        $locator = new ServiceLocator([
+            'foo' => function () { return 'bar'; },
+            'bar' => function (): string { return 'baz'; },
+            'baz' => function (): ?string { return 'zaz'; },
+        ]);
+
+        $this->assertSame($locator->getProvidedServices(), [
+            'foo' => '?',
+            'bar' => 'string',
+            'baz' => '?string',
+        ]);
+    }
 }
 
 class SomeServiceSubscriber implements ServiceSubscriberInterface

src/Symfony/Component/DependencyInjection/composer.json

@@ -18,7 +18,7 @@
     "require": {
         "php": "^7.1.3",
         "psr/container": "^1.0",
-        "symfony/contracts": "^1.0"
+        "symfony/contracts": "^1.1"
     },
     "require-dev": {
         "symfony/yaml": "~3.4|~4.0",

src/Symfony/Contracts/CHANGELOG.md

@@ -6,6 +6,7 @@ CHANGELOG
 
  * added `HttpClient` namespace with contracts for implementing flexible HTTP clients
  * added `EventDispatcher\EventDispatcherInterface`
+ * added `ServiceProviderInterface`
 
 1.0.0
 -----

src/Symfony/Contracts/Service/ServiceLocatorTrait.php

@@ -15,7 +15,7 @@ use Psr\Container\ContainerExceptionInterface;
 use Psr\Container\NotFoundExceptionInterface;
 
 /**
- * A trait to help implement PSR-11 service locators.
+ * A trait to help implement ServiceProviderInterface.
  *
  * @author Robin Chalas <robin.chalas@gmail.com>
  * @author Nicolas Grekas <p@tchwork.com>
@@ -24,6 +24,7 @@ trait ServiceLocatorTrait
 {
     private $factories;
     private $loading = [];
+    private $providedTypes;
 
     /**
      * @param callable[] $factories
@@ -66,6 +67,28 @@ trait ServiceLocatorTrait
         }
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function getProvidedServices(): array
+    {
+        if (null === $this->providedTypes) {
+            $this->providedTypes = [];
+
+            foreach ($this->factories as $name => $factory) {
+                if (!\is_callable($factory)) {
+                    $this->providedTypes[$name] = '?';
+                } else {
+                    $type = (new \ReflectionFunction($factory))->getReturnType();
+
+                    $this->providedTypes[$name] = $type ? ($type->allowsNull() ? '?' : '').$type->getName() : '?';
+                }
+            }
+        }
+
+        return $this->providedTypes;
+    }
+
     private function createNotFoundException(string $id): NotFoundExceptionInterface
     {
         if (!$alternatives = array_keys($this->factories)) {

src/Symfony/Contracts/Service/ServiceProviderInterface.php

@@ -0,0 +1,36 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Contracts\Service;
+
+use Psr\Container\ContainerInterface;
+
+/**
+ * A ServiceProviderInterface exposes the identifiers and the types of services provided by a container.
+ *
+ * @author Nicolas Grekas <p@tchwork.com>
+ * @author Mateusz Sip <mateusz.sip@gmail.com>
+ */
+interface ServiceProviderInterface extends ContainerInterface
+{
+    /**
+     * Returns an associative array of service types keyed by the identifiers provided by the current container.
+     *
+     * Examples:
+     *
+     *  * ['logger' => 'Psr\Log\LoggerInterface'] means the object provides a service named "logger" that implements Psr\Log\LoggerInterface
+     *  * ['foo' => '?'] means the container provides service name "foo" of unspecified type
+     *  * ['bar' => '?Bar\Baz'] means the container provides a service "bar" of type Bar\Baz|null
+     *
+     * @return string[] The provided service types, keyed by service names
+     */
+    public function getProvidedServices(): array;
+}