#20 Impelement ArrayMerge sniff in foreach

Author: Lars Roettig

Magento2/Sniffs/Performance/ForeachArrayMergeSniff.php

@@ -0,0 +1,59 @@
+<?php
+/**
+ * Copyright © Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+namespace Magento2\Sniffs\Performance;
+
+use PHP_CodeSniffer\Files\File;
+use PHP_CodeSniffer\Sniffs\Sniff;
+
+class ForeachArrayMergeSniff implements Sniff
+{
+    /**
+     * String representation of warning.
+     *
+     * @var string
+     */
+    protected $warningMessage = 'Array merge is slow in each functions. ';
+
+    /**
+     * Warning violation code.
+     *
+     * @var string
+     */
+    protected $warningCode = 'ForeachArrayMerge';
+
+    /**
+     * @inheritdoc
+     */
+    public function register()
+    {
+        return [T_FOREACH, T_FOR];
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function process(File $phpcsFile, $stackPtr)
+    {
+        $tokens = $phpcsFile->getTokens();
+
+        $scopeOpener = $tokens[$stackPtr]['scope_opener'];
+        $scopeCloser = $tokens[$stackPtr]['scope_closer'] ;
+
+        for ($i = $scopeOpener; $i <  $scopeCloser; $i++)
+        {
+            $tag = $tokens[$i];
+            if ($tag['code'] !== T_STRING) {
+                continue;
+            }
+            if ($tag['content'] !== 'array_merge') {
+                continue;
+            }
+
+            $phpcsFile->addWarning($this->warningMessage, $i, $this->warningCode);
+        }
+    }
+}

Magento2/Tests/Performance/ForeachArrayMergeUnitTest.inc

@@ -0,0 +1,17 @@
+<?php
+$configurationSources = [
+    0 => 'value',
+    1 => 'value2',
+];
+
+$options = [];
+foreach ($configurationSources as $source) {
+    $options = array_merge($options, $source);
+}
+
+$options = [];
+$itemCount = count($configurationSources);
+for ($i = 0; $i <= $itemCount; $i++) {
+    $source = $options[$itemCount];
+    $options = array_merge($options, $source));
+}

Magento2/Tests/Performance/ForeachArrayMergeUnitTest.php

@@ -0,0 +1,33 @@
+<?php
+/**
+ * Copyright © Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento2\Tests\Performance;
+
+use PHP_CodeSniffer\Tests\Standards\AbstractSniffUnitTest;
+
+/**
+ * Class EmptyCheckUnitTest
+ */
+class ForeachArrayMergeUnitTest  extends AbstractSniffUnitTest
+{
+    /**
+     * @inheritdoc
+     */
+    public function getErrorList()
+    {
+        return [];
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function getWarningList()
+    {
+        return [
+            9 => 1,
+            16 => 1,
+        ];
+    }
+}

Magento2/ruleset.xml

@@ -230,6 +230,10 @@
         <severity>7</severity>
         <type>warning</type>
     </rule>
+    <rule ref="Magento2.Performance.ForeachArrayMerge">
+        <severity>7</severity>
+        <type>warning</type>
+    </rule>
     <rule ref="Magento2.Strings.StringConcat">
         <severity>7</severity>
         <type>warning</type>