[container] get service by name with PHP const (#204)

Author: seferov

src/Handler/ContainerHandler.php

@@ -2,7 +2,9 @@
 
 namespace Psalm\SymfonyPsalmPlugin\Handler;
 
+use function constant;
 use PhpParser\Node\Expr\ClassConstFetch;
+use PhpParser\Node\Identifier;
 use PhpParser\Node\Scalar\String_;
 use Psalm\CodeLocation;
 use Psalm\IssueBuffer;
@@ -73,10 +75,28 @@ public static function afterMethodCallAnalysis(AfterMethodCallAnalysisEvent $eve
             return;
         }
 
-        if ($expr->args[0]->value instanceof String_) {
-            $serviceId = $expr->args[0]->value->value;
-        } elseif ($expr->args[0]->value instanceof ClassConstFetch) {
-            $serviceId = (string) $expr->args[0]->value->class->getAttribute('resolvedName');
+        $idArgument = $expr->args[0]->value;
+
+        if ($idArgument instanceof String_) {
+            $serviceId = $idArgument->value;
+        } elseif ($idArgument instanceof ClassConstFetch) {
+            $className = (string) $idArgument->class->getAttribute('resolvedName');
+            if ('self' === $className) {
+                $className = $event->getStatementsSource()->getSource()->getFQCLN();
+            }
+            if (!$idArgument->name instanceof Identifier || !$className) {
+                return;
+            }
+
+            if ('class' === $idArgument->name->name) {
+                $serviceId = $className;
+            } else {
+                try {
+                    $serviceId = constant($className.'::'.$idArgument->name->name);
+                } catch (\Exception $e) {
+                    return;
+                }
+            }
         } else {
             return;
         }

tests/acceptance/acceptance/ServiceSubscriber.feature

@@ -57,3 +57,19 @@ Feature: Service Subscriber
       | Trace | $service2: Psalm\SymfonyPsalmPlugin\Tests\Fixture\DummyPrivateService |
       | Trace | $service3: Psalm\SymfonyPsalmPlugin\Tests\Fixture\DummyPrivateService |
     And I see no other errors
+
+  Scenario: Asserting psalm recognizes return type of services fetched name by PHP constants.
+    Given I have the following code
+      """
+        public function __invoke()
+        {
+          /** @psalm-trace $service1 */
+          $service1 = $this->container->get(\Psalm\SymfonyPsalmPlugin\Tests\Fixture\DummyPrivateService::CUSTOM_SERVICE_NAME);
+        }
+      }
+      """
+    When I run Psalm
+    Then I see these errors
+      | Type  | Message                                                               |
+      | Trace | $service1: Psalm\SymfonyPsalmPlugin\Tests\Fixture\DummyPrivateService |
+    And I see no other errors

tests/fixture/DummyPrivateService.php

@@ -4,6 +4,8 @@
 
 class DummyPrivateService
 {
+    const CUSTOM_SERVICE_NAME = 'dummy_service_with_locator';
+
     public function foo(): string
     {
         return 'foo';