AC-1102: Static test to verify self-closing tags for non-void html elements

Author: xmav

Magento2/Sniffs/Html/HtmlSelfClosingTagsSniff.php

@@ -0,0 +1,84 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+declare(strict_types=1);
+
+namespace Magento2\Sniffs\Html;
+
+use PHP_CodeSniffer\Sniffs\Sniff;
+use PHP_CodeSniffer\Files\File;
+
+/**
+ * Sniff for self-closing tags
+ */
+class HtmlSelfClosingTagsSniff implements Sniff
+{
+    /**
+     * List of void elements
+     *
+     * https://www.w3.org/TR/html51/syntax.html#writing-html-documents-elements
+     *
+     * @var string[]
+     */
+    private $voidElements = [
+        'area',
+        'base',
+        'br',
+        'col',
+        'embed',
+        'hr',
+        'img',
+        'input',
+        'keygen',
+        'link',
+        'menuitem',
+        'meta',
+        'param',
+        'source',
+        'track',
+        'wbr',
+    ];
+
+    /**
+     * @inheritDoc
+     */
+    public function register()
+    {
+        return [T_INLINE_HTML];
+    }
+
+    /**
+     * Detect use of self-closing tag with non-void html element
+     *
+     * @param File $phpcsFile
+     * @param int $stackPtr
+     * @return int|void
+     */
+    public function process(File $phpcsFile, $stackPtr)
+    {
+        if ($stackPtr !== 0) {
+            return;
+        }
+        $html = $phpcsFile->getTokensAsString($stackPtr, count($phpcsFile->getTokens()));
+
+        if (empty($html)) {
+            return;
+        }
+
+        if (preg_match_all('$<(\w{2,})\s?[^<]*\/>$', $html, $matches, PREG_SET_ORDER)) {
+            foreach ($matches as $match) {
+                if (!in_array($match[1], $this->voidElements)) {
+                    $phpcsFile->addError(
+                        'Avoid using self-closing tag with non-void html element'
+                        . ' - "' . $match[0]  . PHP_EOL,
+                        null,
+                        'HtmlTemplates.Tag.SelfClosing'
+                    );
+                }
+            }
+        }
+    }
+}

Magento2/ruleset.xml

@@ -116,6 +116,11 @@
         <type>error</type>
     </rule>
 
+    <rule ref="Magento2.Html.HtmlSelfClosingTags">
+        <severity>10</severity>
+        <type>error</type>
+        <exclude-pattern>*\.xml$</exclude-pattern>
+    </rule>
     <!-- Severity 9 warnings: Possible security and issues that may cause bugs. -->
     <rule ref="Generic.Files.ByteOrderMark">
         <severity>9</severity>
@@ -153,6 +158,7 @@
     <rule ref="Magento2.Html.HtmlBinding">
         <severity>9</severity>
         <type>warning</type>
+        <exclude-pattern>*\.xml$</exclude-pattern>
     </rule>
 
     <!-- Severity 8 warnings: Magento specific code issues and design violations. -->
@@ -246,6 +252,7 @@
     <rule ref="Magento2.Html.HtmlDirective">
         <severity>8</severity>
         <type>warning</type>
+        <exclude-pattern>*\.xml$</exclude-pattern>
     </rule>
 
     <!-- Severity 7 warnings: General code issues. -->