Do not care about `mailer` service changes

Until now we tried to detect `mailer` service changes,
and always flushed messages for them, just to be safe.

To keep things simple, we don't do this anymore.
If `mailer` gets replaced by another service, flushing will
fail as expected. People should not replace it.

src/Silex/Provider/SwiftmailerServiceProvider.php

@@ -21,7 +21,6 @@ use Silex\ServiceProviderInterface;
  */
 class SwiftmailerServiceProvider implements ServiceProviderInterface
 {
-    private $mailerFactory;
     private $mailerCreated;
 
     public function register(Application $app)
@@ -29,7 +28,7 @@ class SwiftmailerServiceProvider implements ServiceProviderInterface
         $app['swiftmailer.options'] = array();
 
         $self = $this;
-        $app['mailer'] = $this->mailerFactory = $app->share(function () use ($app, $self) {
+        $app['mailer'] = $app->share(function () use ($app, $self) {
             $self->mailerCreated = true;
             return new \Swift_Mailer($app['swiftmailer.spooltransport']);
         });
@@ -94,12 +93,11 @@ class SwiftmailerServiceProvider implements ServiceProviderInterface
 
         $self = $this;
         $app->finish(function () use ($app, $self) {
-            //To speed things up (by avoiding Swift Mailer initialization), flush messages only if
-            //our mailer has been "used" or got replaced by another service we have no knowledge off.
-            if ($app->raw('mailer') === $self->mailerFactory && !$self->mailerCreated) {
-                return;
+            //To speed things up (by avoiding Swift Mailer initialization), flush
+            //messages only if our mailer has been created (potentially used)
+            if ($self->mailerCreated) {
+                $app['swiftmailer.spooltransport']->getSpool()->flushQueue($app['swiftmailer.transport']);
             }
-            $app['swiftmailer.spooltransport']->getSpool()->flushQueue($app['swiftmailer.transport']);
         });
     }
 }

tests/Silex/Tests/Provider/SwiftmailerServiceProviderTest.php

@@ -62,7 +62,7 @@ class SwiftmailerServiceProviderTest extends \PHPUnit_Framework_TestCase
         $this->assertCount(0, $app['swiftmailer.spool']->getMessages());
     }
 
-    public function testSwiftMailerAvoidsFlushesIfPossible()
+    public function testSwiftMailerAvoidsFlushesIfMailerIsUnused()
     {
         $app = new Application();
 
@@ -82,54 +82,4 @@ class SwiftmailerServiceProviderTest extends \PHPUnit_Framework_TestCase
         $app->terminate($request, $response);
         $this->assertFalse($app['swiftmailer.spool']->hasFlushed);
     }
-
-    public function testSwiftMailerWillAlwaysFlushIfServiceChanges()
-    {
-        $app = new Application();
-
-        $app->register(new SwiftmailerServiceProvider());
-        $app->boot();
-
-        $app['swiftmailer.spool'] = $app->share(function () {
-            return new SpoolStub();
-        });
-
-        $app['mailer'] = $app->share(function () {
-            return null; //No need to actually return a mailer instance
-        });
-
-        $app->get('/', function() use ($app) { });
-
-        $request = Request::create('/');
-        $response = $app->handle($request);
-        $this->assertCount(0, $app['swiftmailer.spool']->getMessages());
-
-        $app->terminate($request, $response);
-        $this->assertTrue($app['swiftmailer.spool']->hasFlushed);
-    }
-
-    public function testSwiftMailerWillAlwaysFlushIfServiceIsExtended()
-    {
-        $app = new Application();
-
-        $app->register(new SwiftmailerServiceProvider());
-        $app->boot();
-
-        $app['swiftmailer.spool'] = $app->share(function () {
-            return new SpoolStub();
-        });
-
-        $app->extend('mailer', function ($mailer) {
-            return $mailer;
-        });
-
-        $app->get('/', function() use ($app) { });
-
-        $request = Request::create('/');
-        $response = $app->handle($request);
-        $this->assertCount(0, $app['swiftmailer.spool']->getMessages());
-
-        $app->terminate($request, $response);
-        $this->assertTrue($app['swiftmailer.spool']->hasFlushed);
-    }
 }