Modernize/Dirname: respect a passed php_version

If no `php_version` is passed, the sniff will behave as before.

However, is a `php_version` is passed, the sniff will now selectively stay silent depending on the configured PHP and whether the proposed fixes could be applied.

Includes additional tests.
Includes adding information about the support of the `php_version` config setting to the README docs.

Modernize/Sniffs/FunctionCalls/DirnameSniff.php

@@ -13,6 +13,7 @@
 use PHP_CodeSniffer\Files\File;
 use PHP_CodeSniffer\Sniffs\Sniff;
 use PHP_CodeSniffer\Util\Tokens;
+use PHPCSUtils\BackCompat\Helper;
 use PHPCSUtils\Tokens\Collections;
 use PHPCSUtils\Utils\Context;
 use PHPCSUtils\Utils\PassedParameters;
@@ -25,6 +26,15 @@
 final class DirnameSniff implements Sniff
 {
 
+    /**
+     * PHP version as configured or 0 if unknown.
+     *
+     * @since 1.1.1
+     *
+     * @var int
+     */
+    private $phpVersion;
+
     /**
      * Registers the tokens that this sniff wants to listen for.
      *
@@ -50,6 +60,21 @@ public function register()
      */
     public function process(File $phpcsFile, $stackPtr)
     {
+        if (isset($this->phpVersion) === false || \defined('PHP_CODESNIFFER_IN_TESTS')) {
+            // Set default value to prevent this code from running every time the sniff is triggered.
+            $this->phpVersion = 0;
+
+            $phpVersion = Helper::getConfigData('php_version');
+            if ($phpVersion !== null) {
+                $this->phpVersion = (int) $phpVersion;
+            }
+        }
+
+        if ($this->phpVersion !== 0 && $this->phpVersion < 50300) {
+            // PHP version too low, nothing to do.
+            return;
+        }
+
         $tokens = $phpcsFile->getTokens();
 
         if (\strtolower($tokens[$stackPtr]['content']) !== 'dirname') {
@@ -182,6 +207,11 @@ public function process(File $phpcsFile, $stackPtr)
         /*
          * PHP 7.0+: Detect use of nested calls to dirname().
          */
+        if ($this->phpVersion !== 0 && $this->phpVersion < 70000) {
+            // No need to check for this issue if the PHP version would not allow for it anyway.
+            return;
+        }
+
         if (\preg_match('`^\s*\\\\?dirname\s*\(`i', $pathParam['clean']) !== 1) {
             return;
         }

Modernize/Tests/FunctionCalls/DirnameUnitTest.2.inc

@@ -0,0 +1,10 @@
+<?php
+
+/*
+ * This test file is run with php_version set to a value of 50000.
+ *
+ * Neither of the fixes the sniff offers will be applied as the PHP version is too low.
+ */
+
+$path = dirname(__FILE__);
+$path = dirname(dirname(__DIR__));

Modernize/Tests/FunctionCalls/DirnameUnitTest.2.inc.fixed

@@ -0,0 +1,10 @@
+<?php
+
+/*
+ * This test file is run with php_version set to a value of 50000.
+ *
+ * Neither of the fixes the sniff offers will be applied as the PHP version is too low.
+ */
+
+$path = dirname(__FILE__);
+$path = dirname(dirname(__DIR__));

Modernize/Tests/FunctionCalls/DirnameUnitTest.3.inc

@@ -0,0 +1,11 @@
+<?php
+
+/*
+ * This test file is run with php_version set to a value of 50300.
+ *
+ * The `FileConstant` error code should trigger, but the `Nested` error code
+ * should be ignored as the PHP version is too low.
+ */
+
+$path = dirname(__FILE__);
+$path = dirname(dirname(__DIR__));

Modernize/Tests/FunctionCalls/DirnameUnitTest.3.inc.fixed

@@ -0,0 +1,11 @@
+<?php
+
+/*
+ * This test file is run with php_version set to a value of 50300.
+ *
+ * The `FileConstant` error code should trigger, but the `Nested` error code
+ * should be ignored as the PHP version is too low.
+ */
+
+$path = __DIR__;
+$path = dirname(dirname(__DIR__));

Modernize/Tests/FunctionCalls/DirnameUnitTest.4.inc

@@ -0,0 +1,10 @@
+<?php
+
+/*
+ * This test file is run with php_version set to a value of 70000.
+ *
+ * Both of the fixes the sniff offers will be applied as the PHP version allows for it.
+ */
+
+$path = dirname(__FILE__);
+$path = dirname(dirname(__DIR__));

Modernize/Tests/FunctionCalls/DirnameUnitTest.4.inc.fixed

@@ -0,0 +1,10 @@
+<?php
+
+/*
+ * This test file is run with php_version set to a value of 70000.
+ *
+ * Both of the fixes the sniff offers will be applied as the PHP version allows for it.
+ */
+
+$path = __DIR__;
+$path = dirname(__DIR__, 2);

Modernize/Tests/FunctionCalls/DirnameUnitTest.5.inc

@@ -0,0 +1,7 @@
+<?php
+
+/*
+ * This test file is only here to reset the value of the php_version configuration option.
+ */
+
+dirname($path);

Modernize/Tests/FunctionCalls/DirnameUnitTest.php

@@ -10,6 +10,7 @@
 
 namespace PHPCSExtra\Modernize\Tests\FunctionCalls;
 
+use PHPCSUtils\BackCompat\Helper;
 use PHP_CodeSniffer\Tests\Standards\AbstractSniffUnitTest;
 
 /**
@@ -22,6 +23,35 @@
 final class DirnameUnitTest extends AbstractSniffUnitTest
 {
 
+    /**
+     * Set CLI values before the file is tested.
+     *
+     * @param string                  $testFile The name of the file being tested.
+     * @param \PHP_CodeSniffer\Config $config   The config data for the test run.
+     *
+     * @return void
+     */
+    public function setCliValues($testFile, $config)
+    {
+        switch ($testFile) {
+            case 'DirnameUnitTest.2.inc':
+                Helper::setConfigData('php_version', '50000', true, $config); // PHP 5.0.
+                break;
+
+            case 'DirnameUnitTest.3.inc':
+                Helper::setConfigData('php_version', '50300', true, $config); // PHP 5.3.
+                break;
+
+            case 'DirnameUnitTest.4.inc':
+                Helper::setConfigData('php_version', '70000', true, $config); // PHP 7.0.
+                break;
+
+            default:
+                Helper::setConfigData('php_version', null, true, $config); // No PHP version set.
+                break;
+        }
+    }
+
     /**
      * Returns the lines where errors should occur.
      *
@@ -70,6 +100,17 @@ public function getErrorList($testFile = '')
                     131 => 1,
                 ];
 
+            case 'DirnameUnitTest.3.inc':
+                return [
+                    10 => 1,
+                ];
+
+            case 'DirnameUnitTest.4.inc':
+                return [
+                    9  => 1,
+                    10 => 1,
+                ];
+
             default:
                 return [];
         }

README.md

@@ -126,6 +126,9 @@ This sniff will detect and auto-fix two typical code modernizations which can be
 2. Since PHP 7.0, nested function calls to `dirname()` can be changed to use the `$levels` parameter.
     Errorcode: `Modernize.FunctionCalls.Dirname.Nested`.
 
+If a [`php_version` configuration option][php_version-config] has been passed to PHPCS using either `--config-set` or `--runtime-set`, it will be respected by the sniff.
+In effect, this means that the sniff will only report on modernizations which can be applied for the PHP version as configured.
+
 
 ### NormalizedArrays