feature #18482 Created a trait to sort tagged services (iltar)

This PR was squashed before being merged into the 3.2-dev branch (closes #18482).

Discussion
----------

Created a trait to sort tagged services

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | ~
| License       | MIT
| Doc PR        | ~

When writing the `ControllerArgumentValueResolverPass`, I needed a sorting on `priority`. I ended up copying a method from another class. I noticed this was done more often and 99% of the code was the same. I've moved the most common notation into the trait and "used" the trait in the priority aware passes. This increases horizontal re-use and means people can also use this in their bundles.

The cases that were slightly different, are still working completely. I had to fix some tests because they returned an invalid value from the mocked find method.

Commits
-------

778a70b Created a trait to sort tagged services

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Compiler/AddCacheWarmerPass.php

@@ -11,9 +11,9 @@
 
 namespace Symfony\Bundle\FrameworkBundle\DependencyInjection\Compiler;
 
+use Symfony\Component\DependencyInjection\Compiler\PriorityTaggedServiceTrait;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
-use Symfony\Component\DependencyInjection\Reference;
 
 /**
  * Registers the cache warmers.
@@ -22,6 +22,8 @@
  */
 class AddCacheWarmerPass implements CompilerPassInterface
 {
+    use PriorityTaggedServiceTrait;
+
     /**
      * {@inheritdoc}
      */
@@ -31,20 +33,12 @@ public function process(ContainerBuilder $container)
             return;
         }
 
-        $warmers = array();
-        foreach ($container->findTaggedServiceIds('kernel.cache_warmer') as $id => $attributes) {
-            $priority = isset($attributes[0]['priority']) ? $attributes[0]['priority'] : 0;
-            $warmers[$priority][] = new Reference($id);
-        }
+        $warmers = $this->findAndSortTaggedServices('kernel.cache_warmer', $container);
 
         if (empty($warmers)) {
             return;
         }
 
-        // sort by priority and flatten
-        krsort($warmers);
-        $warmers = call_user_func_array('array_merge', $warmers);
-
         $container->getDefinition('cache_warmer')->replaceArgument(0, $warmers);
     }
 }

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Compiler/ConfigCachePass.php

@@ -12,8 +12,8 @@
 namespace Symfony\Bundle\FrameworkBundle\DependencyInjection\Compiler;
 
 use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
+use Symfony\Component\DependencyInjection\Compiler\PriorityTaggedServiceTrait;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
-use Symfony\Component\DependencyInjection\Reference;
 
 /**
  * Adds services tagged config_cache.resource_checker to the config_cache_factory service, ordering them by priority.
@@ -23,23 +23,16 @@
  */
 class ConfigCachePass implements CompilerPassInterface
 {
+    use PriorityTaggedServiceTrait;
+
     public function process(ContainerBuilder $container)
     {
-        $resourceCheckers = array();
-
-        foreach ($container->findTaggedServiceIds('config_cache.resource_checker') as $id => $tags) {
-            $priority = isset($tags[0]['priority']) ? $tags[0]['priority'] : 0;
-            $resourceCheckers[$priority][] = new Reference($id);
-        }
+        $resourceCheckers = $this->findAndSortTaggedServices('config_cache.resource_checker', $container);
 
         if (empty($resourceCheckers)) {
             return;
         }
 
-        // sort by priority and flatten
-        krsort($resourceCheckers);
-        $resourceCheckers = call_user_func_array('array_merge', $resourceCheckers);
-
         $container->getDefinition('config_cache_factory')->replaceArgument(0, $resourceCheckers);
     }
 }

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Compiler/ControllerArgumentValueResolverPass.php

@@ -12,8 +12,8 @@
 namespace Symfony\Bundle\FrameworkBundle\DependencyInjection\Compiler;
 
 use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
+use Symfony\Component\DependencyInjection\Compiler\PriorityTaggedServiceTrait;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
-use Symfony\Component\DependencyInjection\Reference;
 
 /**
  * Gathers and configures the argument value resolvers.
@@ -22,6 +22,8 @@
  */
 class ControllerArgumentValueResolverPass implements CompilerPassInterface
 {
+    use PriorityTaggedServiceTrait;
+
     public function process(ContainerBuilder $container)
     {
         if (!$container->hasDefinition('argument_resolver')) {
@@ -32,34 +34,4 @@ public function process(ContainerBuilder $container)
         $argumentResolvers = $this->findAndSortTaggedServices('controller.argument_value_resolver', $container);
         $definition->replaceArgument(1, $argumentResolvers);
     }
-
-    /**
-     * Finds all services with the given tag name and order them by their priority.
-     *
-     * @param string           $tagName
-     * @param ContainerBuilder $container
-     *
-     * @return array
-     */
-    private function findAndSortTaggedServices($tagName, ContainerBuilder $container)
-    {
-        $services = $container->findTaggedServiceIds($tagName);
-
-        $sortedServices = array();
-        foreach ($services as $serviceId => $tags) {
-            foreach ($tags as $attributes) {
-                $priority = isset($attributes['priority']) ? $attributes['priority'] : 0;
-                $sortedServices[$priority][] = new Reference($serviceId);
-            }
-        }
-
-        if (empty($sortedServices)) {
-            return array();
-        }
-
-        krsort($sortedServices);
-
-        // Flatten the array
-        return call_user_func_array('array_merge', $sortedServices);
-    }
 }

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Compiler/PropertyInfoPass.php

@@ -12,8 +12,8 @@
 namespace Symfony\Bundle\FrameworkBundle\DependencyInjection\Compiler;
 
 use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
+use Symfony\Component\DependencyInjection\Compiler\PriorityTaggedServiceTrait;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
-use Symfony\Component\DependencyInjection\Reference;
 
 /**
  * Adds extractors to the property_info service.
@@ -22,6 +22,8 @@
  */
 class PropertyInfoPass implements CompilerPassInterface
 {
+    use PriorityTaggedServiceTrait;
+
     /**
      * {@inheritdoc}
      */
@@ -45,34 +47,4 @@ public function process(ContainerBuilder $container)
         $accessExtractors = $this->findAndSortTaggedServices('property_info.access_extractor', $container);
         $definition->replaceArgument(3, $accessExtractors);
     }
-
-    /**
-     * Finds all services with the given tag name and order them by their priority.
-     *
-     * @param string           $tagName
-     * @param ContainerBuilder $container
-     *
-     * @return array
-     */
-    private function findAndSortTaggedServices($tagName, ContainerBuilder $container)
-    {
-        $services = $container->findTaggedServiceIds($tagName);
-
-        $sortedServices = array();
-        foreach ($services as $serviceId => $tags) {
-            foreach ($tags as $attributes) {
-                $priority = isset($attributes['priority']) ? $attributes['priority'] : 0;
-                $sortedServices[$priority][] = new Reference($serviceId);
-            }
-        }
-
-        if (empty($sortedServices)) {
-            return array();
-        }
-
-        krsort($sortedServices);
-
-        // Flatten the array
-        return call_user_func_array('array_merge', $sortedServices);
-    }
 }

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Compiler/SerializerPass.php

@@ -11,9 +11,9 @@
 
 namespace Symfony\Bundle\FrameworkBundle\DependencyInjection\Compiler;
 
+use Symfony\Component\DependencyInjection\Compiler\PriorityTaggedServiceTrait;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
-use Symfony\Component\DependencyInjection\Reference;
 
 /**
  * Adds all services with the tags "serializer.encoder" and "serializer.normalizer" as
@@ -23,6 +23,8 @@
  */
 class SerializerPass implements CompilerPassInterface
 {
+    use PriorityTaggedServiceTrait;
+
     public function process(ContainerBuilder $container)
     {
         if (!$container->hasDefinition('serializer')) {
@@ -31,42 +33,17 @@ public function process(ContainerBuilder $container)
 
         // Looks for all the services tagged "serializer.normalizer" and adds them to the Serializer service
         $normalizers = $this->findAndSortTaggedServices('serializer.normalizer', $container);
+
+        if (empty($normalizers)) {
+            throw new \RuntimeException('You must tag at least one service as "serializer.normalizer" to use the Serializer service');
+        }
         $container->getDefinition('serializer')->replaceArgument(0, $normalizers);
 
         // Looks for all the services tagged "serializer.encoders" and adds them to the Serializer service
         $encoders = $this->findAndSortTaggedServices('serializer.encoder', $container);
-        $container->getDefinition('serializer')->replaceArgument(1, $encoders);
-    }
-
-    /**
-     * Finds all services with the given tag name and order them by their priority.
-     *
-     * @param string           $tagName
-     * @param ContainerBuilder $container
-     *
-     * @return array
-     *
-     * @throws \RuntimeException
-     */
-    private function findAndSortTaggedServices($tagName, ContainerBuilder $container)
-    {
-        $services = $container->findTaggedServiceIds($tagName);
-
-        if (empty($services)) {
-            throw new \RuntimeException(sprintf('You must tag at least one service as "%s" to use the Serializer service', $tagName));
-        }
-
-        $sortedServices = array();
-        foreach ($services as $serviceId => $tags) {
-            foreach ($tags as $attributes) {
-                $priority = isset($attributes['priority']) ? $attributes['priority'] : 0;
-                $sortedServices[$priority][] = new Reference($serviceId);
-            }
+        if (empty($encoders)) {
+            throw new \RuntimeException('You must tag at least one service as "serializer.encoder" to use the Serializer service');
         }
-
-        krsort($sortedServices);
-
-        // Flatten the array
-        return call_user_func_array('array_merge', $sortedServices);
+        $container->getDefinition('serializer')->replaceArgument(1, $encoders);
     }
 }

src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Compiler/AddCacheWarmerPassTest.php

@@ -21,7 +21,7 @@ public function testThatCacheWarmersAreProcessedInPriorityOrder()
         $services = array(
             'my_cache_warmer_service1' => array(0 => array('priority' => 100)),
             'my_cache_warmer_service2' => array(0 => array('priority' => 200)),
-            'my_cache_warmer_service3' => array(),
+            'my_cache_warmer_service3' => array(0 => array()),
         );
 
         $definition = $this->getMock('Symfony\Component\DependencyInjection\Definition');

src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Compiler/ConfigCachePassTest.php

@@ -21,7 +21,7 @@ public function testThatCheckersAreProcessedInPriorityOrder()
         $services = array(
             'checker_2' => array(0 => array('priority' => 100)),
             'checker_1' => array(0 => array('priority' => 200)),
-            'checker_3' => array(),
+            'checker_3' => array(0 => array()),
         );
 
         $definition = $this->getMock('Symfony\Component\DependencyInjection\Definition');
@@ -52,7 +52,6 @@ public function testThatCheckersAreProcessedInPriorityOrder()
 
     public function testThatCheckersCanBeMissing()
     {
-        $definition = $this->getMock('Symfony\Component\DependencyInjection\Definition');
         $container = $this->getMock(
             'Symfony\Component\DependencyInjection\ContainerBuilder',
             array('findTaggedServiceIds')

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

@@ -0,0 +1,47 @@
+<?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\Component\DependencyInjection\Compiler;
+
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\DependencyInjection\Reference;
+
+/**
+ * Trait that allows a generic method to find and sort service by priority option in the tag.
+ *
+ * @author Iltar van der Berg <kjarli@gmail.com>
+ */
+trait PriorityTaggedServiceTrait
+{
+    /**
+     * Finds all services with the given tag name and order them by their priority.
+     *
+     * @param string           $tagName
+     * @param ContainerBuilder $container
+     *
+     * @return Reference[]
+     */
+    private function findAndSortTaggedServices($tagName, ContainerBuilder $container)
+    {
+        $services = $container->findTaggedServiceIds($tagName);
+
+        $queue = new \SplPriorityQueue();
+
+        foreach ($services as $serviceId => $tags) {
+            foreach ($tags as $attributes) {
+                $priority = isset($attributes['priority']) ? $attributes['priority'] : 0;
+                $queue->insert(new Reference($serviceId), $priority * -1);
+            }
+        }
+
+        return iterator_to_array($queue);
+    }
+}