Move array_merge calls out of loops to improve performance

Author: simonberger

ContainerBuilder.php

@@ -1280,10 +1280,10 @@ public function findTags()
     {
         $tags = [];
         foreach ($this->getDefinitions() as $id => $definition) {
-            $tags = array_merge(array_keys($definition->getTags()), $tags);
+            $tags[] = array_keys($definition->getTags());
         }
 
-        return array_unique($tags);
+        return array_unique(array_merge([], ...$tags));
     }
 
     /**

Dumper/GraphvizDumper.php

@@ -130,23 +130,22 @@ private function findEdges(string $id, array $arguments, bool $required, string
                     $lazyEdge = $lazy || $this->container->getDefinition((string) $argument)->isLazy();
                 }
 
-                $edges[] = ['name' => $name, 'required' => $required, 'to' => $argument, 'lazy' => $lazyEdge];
+                $edges[] = [['name' => $name, 'required' => $required, 'to' => $argument, 'lazy' => $lazyEdge]];
             } elseif ($argument instanceof ArgumentInterface) {
-                $edges = array_merge($edges, $this->findEdges($id, $argument->getValues(), $required, $name, true));
+                $edges[] = $this->findEdges($id, $argument->getValues(), $required, $name, true);
             } elseif ($argument instanceof Definition) {
-                $edges = array_merge($edges,
-                    $this->findEdges($id, $argument->getArguments(), $required, ''),
-                    $this->findEdges($id, $argument->getProperties(), false, '')
-                );
+                $edges[] = $this->findEdges($id, $argument->getArguments(), $required, '');
+                $edges[] = $this->findEdges($id, $argument->getProperties(), false, '');
+
                 foreach ($argument->getMethodCalls() as $call) {
-                    $edges = array_merge($edges, $this->findEdges($id, $call[1], false, $call[0].'()'));
+                    $edges[] = $this->findEdges($id, $call[1], false, $call[0].'()');
                 }
             } elseif (\is_array($argument)) {
-                $edges = array_merge($edges, $this->findEdges($id, $argument, $required, $name, $lazy));
+                $edges[] = $this->findEdges($id, $argument, $required, $name, $lazy);
             }
         }
 
-        return $edges;
+        return array_merge([], ...$edges);
     }
 
     private function findNodes(): array

Tests/ContainerBuilderTest.php

@@ -1753,6 +1753,18 @@ public function testReferencingDeprecatedPublicService()
 
         $this->addToAssertionCount(1);
     }
+
+    public function testFindTags()
+    {
+        $container = new ContainerBuilder();
+        $container
+            ->register(A::class)
+            ->addTag('tag1')
+            ->addTag('tag2')
+            ->addTag('tag3');
+
+        $this->assertSame(['tag1', 'tag2', 'tag3'], $container->findTags());
+    }
 }
 
 class FooClass