Modernize: Config: use class constant for constant array [1]

Author: jrfnl

src/Config.php

@@ -122,6 +122,18 @@ class Config
         'no-cache'         => 'cache',
     ];
 
+    /**
+     * A list of valid generators.
+     *
+     * @var array<string, string> Keys are the lowercase version of the generator name, while values
+     *                            are the name of the associated PHP generator class.
+     */
+    private const VALID_GENERATORS = [
+        'text'     => 'Text',
+        'html'     => 'HTML',
+        'markdown' => 'Markdown',
+    ];
+
     /**
      * An array of settings that PHPCS and PHPCBF accept.
      *
@@ -191,21 +203,6 @@ class Config
      */
     private $cliArgs = [];
 
-    /**
-     * A list of valid generators.
-     *
-     * {@internal Once support for PHP < 5.6 is dropped, this property should be refactored into a
-     * class constant.}
-     *
-     * @var array<string, string> Keys are the lowercase version of the generator name, while values
-     *                            are the associated PHP generator class.
-     */
-    private $validGenerators = [
-        'text'     => 'Text',
-        'html'     => 'HTML',
-        'markdown' => 'Markdown',
-    ];
-
     /**
      * Command line values that the user has supplied directly.
      *
@@ -1250,8 +1247,8 @@ public function processLongArgument($arg, $pos)
                 $generatorName          = substr($arg, 10);
                 $lowerCaseGeneratorName = strtolower($generatorName);
 
-                if (isset($this->validGenerators[$lowerCaseGeneratorName]) === false) {
-                    $validOptions = implode(', ', $this->validGenerators);
+                if (isset(self::VALID_GENERATORS[$lowerCaseGeneratorName]) === false) {
+                    $validOptions = implode(', ', self::VALID_GENERATORS);
                     $validOptions = substr_replace($validOptions, ' and', strrpos($validOptions, ','), 1);
                     $error        = sprintf(
                         'ERROR: "%s" is not a valid generator. The following generators are supported: %s.'.PHP_EOL.PHP_EOL,
@@ -1262,7 +1259,7 @@ public function processLongArgument($arg, $pos)
                     throw new DeepExitException($error, ExitCode::PROCESS_ERROR);
                 }
 
-                $this->generator = $this->validGenerators[$lowerCaseGeneratorName];
+                $this->generator = self::VALID_GENERATORS[$lowerCaseGeneratorName];
                 $this->overriddenDefaults['generator'] = true;
             } else if (substr($arg, 0, 9) === 'encoding=') {
                 if (isset($this->overriddenDefaults['encoding']) === true) {