Replace multiple string concatenation by joining array of strings

Author: andrey-legayev

lib/internal/Magento/Framework/App/ObjectManager/ConfigLoader/Compiled.php

@@ -42,6 +42,6 @@ public function load($area)
     public static function getFilePath($area)
     {
         $diPath = DirectoryList::getDefaultConfig()[DirectoryList::GENERATED_METADATA][DirectoryList::PATH];
-        return BP . '/' . $diPath . '/' . $area . '.php';
+        return join('', [BP, '/', $diPath, '/', $area, '.php']);
     }
 }

lib/internal/Magento/Framework/View/Element/AbstractBlock.php

@@ -517,9 +517,14 @@ public function getChildHtml($alias = '', $useCache = true)
                 $out = $layout->renderElement($childName, $useCache);
             }
         } else {
+            $outParts = [];
             foreach ($layout->getChildNames($name) as $child) {
-                $out .= $layout->renderElement($child, $useCache);
+                $elementHtml = $layout->renderElement($child, $useCache);
+                if (!empty($elementHtml)) {
+                    $outParts[] = $elementHtml;
+                }
             }
+            $out = join('', $outParts);
         }
 
         return $out;
@@ -548,9 +553,14 @@ public function getChildChildHtml($alias, $childChildAlias = '', $useCache = tru
             $childChildName = $layout->getChildName($childName, $childChildAlias);
             $out = $layout->renderElement($childChildName, $useCache);
         } else {
+            $outParts = [];
             foreach ($layout->getChildNames($childName) as $childChild) {
-                $out .= $layout->renderElement($childChild, $useCache);
+                $elementHtml = $layout->renderElement($childChild, $useCache);
+                if (!empty($elementHtml)) {
+                    $outParts[] = $elementHtml;
+                }
             }
+            $out = join('', $outParts);
         }
         return $out;
     }

lib/internal/Magento/Framework/View/Layout.php

@@ -586,13 +586,16 @@ protected function _renderUiComponent($name)
      */
     protected function _renderContainer($name, $useCache = true)
     {
-        $html = '';
+        $htmlParts = [];
         $children = $this->getChildNames($name);
         foreach ($children as $child) {
-            $html .= $this->renderElement($child, $useCache);
+            $childHtml = $this->renderElement($child, $useCache);
+            if (!empty($childHtml)) {
+                $htmlParts[] = $childHtml;
+            }
         }
-        if ($html == '' || !$this->structure->getAttribute($name, Element::CONTAINER_OPT_HTML_TAG)) {
-            return $html;
+        if (empty($htmlParts) || !$this->structure->getAttribute($name, Element::CONTAINER_OPT_HTML_TAG)) {
+            return join('', $htmlParts);
         }
 
         $htmlId = $this->structure->getAttribute($name, Element::CONTAINER_OPT_HTML_ID);
@@ -606,8 +609,7 @@ protected function _renderContainer($name, $useCache = true)
         }
 
         $htmlTag = $this->structure->getAttribute($name, Element::CONTAINER_OPT_HTML_TAG);
-
-        $html = sprintf('<%1$s%2$s%3$s>%4$s</%1$s>', $htmlTag, $htmlId, $htmlClass, $html);
+        $html = sprintf('<%1$s%2$s%3$s>%4$s</%1$s>', $htmlTag, $htmlId, $htmlClass, join('', $htmlParts));
 
         return $html;
     }