Created Sniff to validate function without argument

Author: anzin

Magento2/Sniffs/Functions/DeprecatedFunctionSniff.php

@@ -0,0 +1,64 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento2\Sniffs\Functions;
+
+use PHP_CodeSniffer\Files\File;
+use PHP_CodeSniffer\Sniffs\Sniff;
+
+/**
+ * Sniff to validate PHP deprecated function.
+ */
+class DeprecatedFunctionSniff implements Sniff
+{
+    /**
+     * Deprecated functions without argument.
+     *
+     * @var array
+     */
+    private $deprecatedFunctions = [
+        'mb_check_encoding'
+    ];
+
+    /**
+     * @inheritdoc
+     */
+    public function register(): array
+    {
+        return [
+            T_OPEN_TAG
+        ];
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function process(File $phpcsFile, $stackPtr): void
+    {
+        $tokens = $phpcsFile->getTokens();
+
+        foreach ($this->deprecatedFunctions as $deprecatedFunction) {
+            $deprecatedFunctionKeys = array_keys(array_column($tokens, 'content'), $deprecatedFunction);
+
+            foreach ($deprecatedFunctionKeys as $deprecatedFunctionKey) {
+                $openParenthesis = $phpcsFile->findNext(T_OPEN_PARENTHESIS, $deprecatedFunctionKey);
+                $closeParenthesis = $phpcsFile->findNext(T_CLOSE_PARENTHESIS, $openParenthesis);
+                $argumentString = trim(
+                    $phpcsFile->getTokensAsString($openParenthesis + 1, $closeParenthesis - $openParenthesis - 1)
+                );
+
+                if (!$argumentString) {
+                    $warningMessage = sprintf(
+                        'Calling function %s() without argument is deprecated in PHP 8.1',
+                        $deprecatedFunction
+                    );
+                    $phpcsFile->addWarning($warningMessage, $deprecatedFunctionKey, 'DeprecatedFunction');
+                }
+            }
+        }
+    }
+}

Magento2/Tests/Functions/DeprecatedFunctionUnitTest.inc

@@ -0,0 +1,32 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento2\Tests\Functions;
+
+/**
+ * Class to test PHP deprecated function.
+ */
+class DeprecatedFunction
+{
+    /**
+     * Test deprecation function.
+     *
+     * @return bool
+     */
+    public function testDeprecatedMethod(): bool
+    {
+        // Warning: function is deprecated without argument.
+        $testMethodParam = mb_check_encoding();
+
+        if ($testMethodParam) {
+            // The function is work correct.
+            $testMethodParam = mb_check_encoding('test-argument', null);
+        }
+
+        return $testMethodParam;
+    }
+}

Magento2/Tests/Functions/DeprecatedFunctionUnitTest.php

@@ -0,0 +1,38 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento2\Tests\Functions;
+
+use PHP_CodeSniffer\Tests\Standards\AbstractSniffUnitTest;
+
+/**
+ * Sniff to validate PHP deprecated function.
+ */
+class DeprecatedFunctionUnitTest extends AbstractSniffUnitTest
+{
+    /**
+     * @inheritdoc
+     */
+    public function getErrorList(): array
+    {
+        return [];
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function getWarningList($testFile = ''): array
+    {
+        if ($testFile === 'DeprecatedFunctionUnitTest.inc') {
+            return [
+                23 => 1
+            ];
+        }
+
+        return [];
+    }
+}

Magento2/ruleset.xml

@@ -251,6 +251,11 @@
         <exclude-pattern>*Test.php</exclude-pattern>
         <exclude-pattern>*/tests/*</exclude-pattern>
     </rule>
+    <rule ref="Magento2.Functions.DeprecatedFunction">
+        <severity>7</severity>
+        <type>warning</type>
+        <exclude-pattern>*\.xml$</exclude-pattern>
+    </rule>
     <rule ref="Magento2.Namespaces.ImportsFromTestNamespace">
         <severity>8</severity>
         <type>warning</type>