[container] support service subscriber & locator

README.md

@@ -12,6 +12,7 @@ vendor/bin/psalm-plugin enable psalm/plugin-symfony
 ### Features
 
 - Detect `ContainerInterface::get()` result type. Works better if you [configure](#configuration) compiled container XML file.
+- Support [Service Subscribers](https://github.com/psalm/psalm-plugin-symfony/issues/20).
 - Detect return type of console arguments (`InputInterface::getArgument()`) and options (`InputInterface::getOption()`). Enforces
 to use InputArgument and InputOption constants as a part of best practise.
 - Detects correct Doctrine repository class if entities are configured with annotations.

src/Handler/ContainerHandler.php

@@ -5,7 +5,10 @@
 use PhpParser\Node\Expr;
 use PhpParser\Node\Expr\ClassConstFetch;
 use PhpParser\Node\Scalar\String_;
+use PhpParser\Node\Stmt\Class_;
 use PhpParser\Node\Stmt\ClassLike;
+use PhpParser\Node\Stmt\ClassMethod;
+use PhpParser\Node\Stmt\Return_;
 use Psalm\Codebase;
 use Psalm\CodeLocation;
 use Psalm\Context;
@@ -19,6 +22,7 @@
 use Psalm\SymfonyPsalmPlugin\Issue\PrivateService;
 use Psalm\SymfonyPsalmPlugin\Issue\ServiceNotFound;
 use Psalm\SymfonyPsalmPlugin\Symfony\ContainerMeta;
+use Psalm\SymfonyPsalmPlugin\Symfony\Service;
 use Psalm\Type\Atomic\TNamedObject;
 use Psalm\Type\Union;
 
@@ -58,7 +62,7 @@ public static function afterMethodCallAnalysis(
         if (!self::isContainerMethod($declaring_method_id, 'get')) {
             if (self::isContainerMethod($declaring_method_id, 'getparameter')) {
                 $argument = $expr->args[0]->value;
-                if ($argument instanceof String_ && !self::followsNamingConvention($argument->value)) {
+                if ($argument instanceof String_ && !self::followsNamingConvention($argument->value) && false === strpos($argument->value, '\\')) {
                     IssueBuffer::accepts(
                         new NamingConventionViolation(new CodeLocation($statements_source, $argument)),
                         $statements_source->getSuppressedIssues()
@@ -90,7 +94,7 @@ public static function afterMethodCallAnalysis(
 
         $service = self::$containerMeta->get($serviceId);
         if ($service) {
-            if (!self::followsNamingConvention($serviceId) && !class_exists($service->getClassName())) {
+            if (!self::followsNamingConvention($serviceId) && false === strpos($serviceId, '\\')) {
                 IssueBuffer::accepts(
                     new NamingConventionViolation(new CodeLocation($statements_source, $expr->args[0]->value)),
                     $statements_source->getSuppressedIssues()
@@ -130,14 +134,46 @@ public static function afterClassLikeVisit(
         Codebase $codebase,
         array &$file_replacements = []
     ) {
+        $fileStorage = $codebase->file_storage_provider->get($statements_source->getFilePath());
+
         if (\in_array($storage->name, ContainerHandler::GET_CLASSLIKES)) {
             if (self::$containerMeta) {
-                $file_path = $statements_source->getFilePath();
-                $file_storage = $codebase->file_storage_provider->get($file_path);
-
                 foreach (self::$containerMeta->getClassNames() as $className) {
                     $codebase->queueClassLikeForScanning($className);
-                    $file_storage->referenced_classlikes[strtolower($className)] = $className;
+                    $fileStorage->referenced_classlikes[strtolower($className)] = $className;
+                }
+            }
+        }
+
+        // see https://symfony.com/doc/current/service_container/service_subscribers_locators.html
+        if (self::$containerMeta && $stmt instanceof Class_ && isset($storage->class_implements['symfony\contracts\service\servicesubscriberinterface'])) {
+            foreach ($stmt->stmts as $classStmt) {
+                if ($classStmt instanceof ClassMethod && 'getSubscribedServices' === $classStmt->name->name && $classStmt->stmts) {
+                    foreach ($classStmt->stmts as $methodStmt) {
+                        if ($methodStmt instanceof Return_ && ($return = $methodStmt->expr) && $return instanceof Expr\Array_) {
+                            foreach ($return->items as $arrayItem) {
+                                if ($arrayItem instanceof Expr\ArrayItem) {
+                                    $value = $arrayItem->value;
+                                    if (!$value instanceof Expr\ClassConstFetch) {
+                                        continue;
+                                    }
+
+                                    /** @var string $className */
+                                    $className = $value->class->getAttribute('resolvedName');
+
+                                    $key = $arrayItem->key;
+                                    $serviceId = $key instanceof String_ ? $key->value : $className;
+
+                                    $service = new Service($serviceId, $className);
+                                    $service->setIsPublic(true);
+                                    self::$containerMeta->add($service);
+
+                                    $codebase->queueClassLikeForScanning($className);
+                                    $fileStorage->referenced_classlikes[strtolower($className)] = $className;
+                                }
+                            }
+                        }
+                    }
                 }
             }
         }

src/Symfony/ContainerMeta.php

@@ -33,7 +33,7 @@ public function get(string $id): ?Service
         return null;
     }
 
-    private function add(Service $service): void
+    public function add(Service $service): void
     {
         if (($alias = $service->getAlias()) && isset($this->services[$alias])) {
             $aliasedService = $this->services[$alias];

tests/acceptance/acceptance/ServiceSubscriber.feature

@@ -0,0 +1,64 @@
+@symfony-4 @symfony-5
+Feature: Service Subscriber
+
+  Background:
+    Given I have the following config
+      """
+      <?xml version="1.0"?>
+      <psalm errorLevel="1">
+        <projectFiles>
+          <directory name="."/>
+          <ignoreFiles> <directory name="../../vendor"/> </ignoreFiles>
+        </projectFiles>
+
+        <plugins>
+          <pluginClass class="Psalm\SymfonyPsalmPlugin\Plugin">
+            <containerXml>../../tests/acceptance/container.xml</containerXml>
+          </pluginClass>
+        </plugins>
+      </psalm>
+      """
+
+  Scenario: Asserting psalm recognizes return type of services defined in getSubscribedServices
+    Given I have the following code
+      """
+      <?php
+
+      use Doctrine\ORM\EntityManagerInterface;
+      use Psr\Container\ContainerInterface;
+      use Symfony\Contracts\Service\ServiceSubscriberInterface;
+      use Symfony\Component\Validator\Validator\ValidatorInterface;
+
+      class SomeController implements ServiceSubscriberInterface
+      {
+        private $container;
+
+        public function __construct(ContainerInterface $container)
+        {
+          $this->container = $container;
+        }
+
+        public function __invoke()
+        {
+          /** @psalm-trace $entityManager */
+          $entityManager = $this->container->get('em');
+
+          /** @psalm-trace $validator */
+          $validator = $this->container->get(ValidatorInterface::class);
+        }
+
+        public static function getSubscribedServices()
+        {
+          return [
+            'em' => EntityManagerInterface::class, // with key
+            ValidatorInterface::class, // without key
+          ];
+        }
+      }
+      """
+    When I run Psalm
+    Then I see these errors
+      | Type  | Message                                                              |
+      | Trace | $entityManager: Doctrine\ORM\EntityManagerInterface                  |
+      | Trace | $validator: Symfony\Component\Validator\Validator\ValidatorInterface |
+    And I see no other errors