bug #20995 [DependencyInjection] Fix the priority order of compiler pass trait (francoispluchino)

This PR was merged into the 3.2 branch.

Discussion
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[DependencyInjection] Fix the priority order of compiler pass trait

| Q             | A
| ------------- | ---
| Branch?       | 3.2
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #20332, #20993
| License       | MIT
| Doc PR        | ~

A regression has appeared between the version `3.1` and `3.2` on the compilation passes using a priority option (see #20332).

Indeed, the order is no longer preserved for service definitions with the same priority. This is caused by the `SplPriorityQueue` class that does not have a FIFO implementation (see this [comment](symfony/symfony#20332 (comment))).

The PR #20993 fixes the problem but only for Forms, not for all compiler passes using the `PriorityTaggedServiceTrait` trait since `3.2`.

Commits
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aac9a7e Fix the priority order of compiler pass trait

Author: nicolas-grekas

Compiler/PriorityTaggedServiceTrait.php

@@ -24,24 +24,34 @@ trait PriorityTaggedServiceTrait
     /**
      * Finds all services with the given tag name and order them by their priority.
      *
+     * The order of additions must be respected for services having the same priority,
+     * and knowing that the \SplPriorityQueue class does not respect the FIFO method,
+     * we should not use this class.
+     *
+     * @see https://bugs.php.net/bug.php?id=53710
+     * @see https://bugs.php.net/bug.php?id=60926
+     *
      * @param string           $tagName
      * @param ContainerBuilder $container
      *
      * @return Reference[]
      */
     private function findAndSortTaggedServices($tagName, ContainerBuilder $container)
     {
-        $services = $container->findTaggedServiceIds($tagName);
-
-        $queue = new \SplPriorityQueue();
+        $services = array();
 
-        foreach ($services as $serviceId => $tags) {
+        foreach ($container->findTaggedServiceIds($tagName) as $serviceId => $tags) {
             foreach ($tags as $attributes) {
                 $priority = isset($attributes['priority']) ? $attributes['priority'] : 0;
-                $queue->insert(new Reference($serviceId), $priority);
+                $services[$priority][] = new Reference($serviceId);
             }
         }
 
-        return iterator_to_array($queue, false);
+        if ($services) {
+            krsort($services);
+            $services = call_user_func_array('array_merge', $services);
+        }
+
+        return $services;
     }
 }

Tests/Compiler/PriorityTaggedServiceTraitTest.php

@@ -33,6 +33,12 @@ public function testThatCacheWarmersAreProcessedInPriorityOrder()
             'my_service11' => array('my_custom_tag' => array('priority' => -1001)),
             'my_service12' => array('my_custom_tag' => array('priority' => -1002)),
             'my_service13' => array('my_custom_tag' => array('priority' => -1003)),
+            'my_service14' => array('my_custom_tag' => array('priority' => -1000)),
+            'my_service15' => array('my_custom_tag' => array('priority' => 1)),
+            'my_service16' => array('my_custom_tag' => array('priority' => -1)),
+            'my_service17' => array('my_custom_tag' => array('priority' => 200)),
+            'my_service18' => array('my_custom_tag' => array('priority' => 100)),
+            'my_service19' => array('my_custom_tag' => array()),
         );
 
         $container = new ContainerBuilder();
@@ -47,15 +53,21 @@ public function testThatCacheWarmersAreProcessedInPriorityOrder()
 
         $expected = array(
             new Reference('my_service2'),
+            new Reference('my_service17'),
             new Reference('my_service1'),
+            new Reference('my_service18'),
             new Reference('my_service8'),
+            new Reference('my_service15'),
             new Reference('my_service4'),
+            new Reference('my_service19'),
             new Reference('my_service5'),
+            new Reference('my_service16'),
             new Reference('my_service9'),
             new Reference('my_service7'),
             new Reference('my_service6'),
             new Reference('my_service3'),
             new Reference('my_service10'),
+            new Reference('my_service14'),
             new Reference('my_service11'),
             new Reference('my_service12'),
             new Reference('my_service13'),