feature #864 [MCP Bundle] Make MonologBundle optional (camilleislasse)

This PR was squashed before being merged into the main branch.

Discussion
----------

[MCP Bundle] Make MonologBundle optional

  | Q             | A
  | ------------- | ---
  | Bug fix?      | yes
  | New feature?  | no
  | Docs?         | no
  | Issues        | Fix #830
  | License       | MIT

This PR makes MonologBundle optional dependency for McpBundle. Without it installed, the container compilation was failing with "Parent definition' monolog.logger_prototype' does not exist."

## Changes

  - Wrap `monolog.logger.mcp` service creation in `class_exists()` check
  - Add `->nullOnInvalid()` to `setLogger()` call in services.php
  - Uniformize logger references: both McpCommand and McpController now use `monolog.logger.mcp` with `NULL_ON_INVALID_REFERENCE`
  - Update test to skip when MonologBundle is not installed

## Credits

Builds on the initial work in #849 by `@WebMamba`. That PR protected service creation but the service was still referenced without protection. This PR completes the fix by also protecting the service usage.

Commits
-------

f3149d6 [MCP Bundle] Make MonologBundle optional

Author: OskarStark

src/mcp-bundle/composer.json

@@ -28,7 +28,8 @@
     "require-dev": {
         "phpstan/phpstan": "^2.1",
         "phpstan/phpstan-strict-rules": "^2.0",
-        "phpunit/phpunit": "^11.5.46"
+        "phpunit/phpunit": "^11.5.46",
+        "symfony/monolog-bundle": "^3.10 || ^4.0"
     },
     "minimum-stability": "dev",
     "prefer-stable": true,

src/mcp-bundle/config/services.php

@@ -17,28 +17,26 @@
 
 return static function (ContainerConfigurator $container): void {
     $container->services()
-        ->set('monolog.logger.mcp')
-            ->parent('monolog.logger_prototype')
-            ->args(['mcp'])
-            ->tag('monolog.logger', ['channel' => 'mcp'])
-
         ->set('mcp.registry', Registry::class)
-            ->args([service('event_dispatcher'), service('monolog.logger.mcp')])
+            ->args([service('event_dispatcher'), service('logger')])
+            ->tag('monolog.logger', ['channel' => 'mcp'])
 
         ->set('mcp.server.builder', Builder::class)
             ->factory([Server::class, 'builder'])
             ->call('setServerInfo', [param('mcp.app'), param('mcp.version')])
             ->call('setPaginationLimit', [param('mcp.pagination_limit')])
             ->call('setInstructions', [param('mcp.instructions')])
-            ->call('setLogger', [service('monolog.logger.mcp')])
             ->call('setEventDispatcher', [service('event_dispatcher')])
             ->call('setRegistry', [service('mcp.registry')])
             ->call('setSession', [service('mcp.session.store')])
             ->call('addRequestHandlers', [tagged_iterator('mcp.request_handler')])
             ->call('addNotificationHandlers', [tagged_iterator('mcp.notification_handler')])
             ->call('addLoaders', [tagged_iterator('mcp.loader')])
             ->call('setDiscovery', [param('kernel.project_dir'), param('mcp.discovery.scan_dirs'), param('mcp.discovery.exclude_dirs')])
+            ->call('setLogger', [service('logger')])
+            ->tag('monolog.logger', ['channel' => 'mcp'])
 
         ->set('mcp.server', Server::class)
-            ->factory([service('mcp.server.builder'), 'build']);
+            ->factory([service('mcp.server.builder'), 'build'])
+    ;
 };

src/mcp-bundle/src/Command/McpCommand.php

@@ -24,7 +24,7 @@ class McpCommand extends Command
 {
     public function __construct(
         private readonly Server $server,
-        private readonly LoggerInterface $logger,
+        private readonly ?LoggerInterface $logger = null,
     ) {
         parent::__construct();
     }

src/mcp-bundle/src/McpBundle.php

@@ -32,7 +32,6 @@
 use Symfony\Component\Config\Definition\Configurator\DefinitionConfigurator;
 use Symfony\Component\DependencyInjection\ChildDefinition;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
-use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;
 use Symfony\Component\DependencyInjection\Reference;
@@ -144,7 +143,8 @@ private function configureClient(array $transports, array $httpConfig, Container
                     new Reference('mcp.server'),
                     new Reference('logger'),
                 ])
-                ->addTag('console.command');
+                ->addTag('console.command')
+                ->addTag('monolog.logger', ['channel' => 'mcp']);
         }
 
         if ($transports['http']) {
@@ -155,10 +155,11 @@ private function configureClient(array $transports, array $httpConfig, Container
                     new Reference('mcp.http_foundation_factory'),
                     new Reference('mcp.psr17_factory'),
                     new Reference('mcp.psr17_factory'),
-                    new Reference('monolog.logger.mcp', ContainerInterface::NULL_ON_INVALID_REFERENCE),
+                    new Reference('logger'),
                 ])
                 ->setPublic(true)
-                ->addTag('controller.service_arguments');
+                ->addTag('controller.service_arguments')
+                ->addTag('monolog.logger', ['channel' => 'mcp']);
         }
 
         $container->register('mcp.server.route_loader', RouteLoader::class)

src/mcp-bundle/tests/DependencyInjection/McpBundleTest.php

@@ -51,19 +51,6 @@ public function testCustomConfiguration()
         $this->assertSame('This server provides weather and calendar tools', $container->getParameter('mcp.instructions'));
     }
 
-    public function testMcpLoggerServiceIsCreated()
-    {
-        $container = $this->buildContainer([]);
-
-        $this->assertTrue($container->hasDefinition('monolog.logger.mcp'));
-
-        $definition = $container->getDefinition('monolog.logger.mcp');
-        $this->assertInstanceOf(\Symfony\Component\DependencyInjection\ChildDefinition::class, $definition);
-        $this->assertSame('monolog.logger_prototype', $definition->getParent());
-        $this->assertSame(['mcp'], $definition->getArguments());
-        $this->assertTrue($definition->hasTag('monolog.logger'));
-    }
-
     #[DataProvider('provideClientTransportsConfiguration')]
     public function testClientTransportsConfiguration(array $config, array $expectedServices)
     {