refactor: deprecate EVENT_PRIORITY_* and add class constants

Author: kenjis

app/Config/Constants.php

@@ -77,3 +77,18 @@
 defined('EXIT_DATABASE')       || define('EXIT_DATABASE', 8); // database error
 defined('EXIT__AUTO_MIN')      || define('EXIT__AUTO_MIN', 9); // lowest automatically-assigned error code
 defined('EXIT__AUTO_MAX')      || define('EXIT__AUTO_MAX', 125); // highest automatically-assigned error code
+
+/**
+ * @deprecated Use \CodeIgniter\Events\Events::PRIORITY_LOW instead.
+ */
+define('EVENT_PRIORITY_LOW', 200);
+
+/**
+ * @deprecated Use \CodeIgniter\Events\Events::PRIORITY_NORMAL instead.
+ */
+define('EVENT_PRIORITY_NORMAL', 100);
+
+/**
+ * @deprecated Use \CodeIgniter\Events\Events::PRIORITY_HIGH instead.
+ */
+define('EVENT_PRIORITY_HIGH', 10);

system/Events/Events.php

@@ -14,15 +14,15 @@
 use Config\Modules;
 use Config\Services;
 
-define('EVENT_PRIORITY_LOW', 200);
-define('EVENT_PRIORITY_NORMAL', 100);
-define('EVENT_PRIORITY_HIGH', 10);
-
 /**
  * Events
  */
 class Events
 {
+    public const PRIORITY_LOW    = 200;
+    public const PRIORITY_NORMAL = 100;
+    public const PRIORITY_HIGH   = 10;
+
     /**
      * The list of listeners.
      *

tests/system/Events/EventsTest.php

@@ -157,15 +157,15 @@ public function testPriorityWithMultiple()
 
         Events::on('foo', static function () use (&$result) {
             $result[] = 'a';
-        }, EVENT_PRIORITY_NORMAL);
+        }, Events::PRIORITY_NORMAL);
 
         Events::on('foo', static function () use (&$result) {
             $result[] = 'b';
-        }, EVENT_PRIORITY_LOW);
+        }, Events::PRIORITY_LOW);
 
         Events::on('foo', static function () use (&$result) {
             $result[] = 'c';
-        }, EVENT_PRIORITY_HIGH);
+        }, Events::PRIORITY_HIGH);
 
         Events::on('foo', static function () use (&$result) {
             $result[] = 'd';