[Scoped] Load early preload.php on scoped bootstrap.php on phpunit 12+ running (#7451)

* [Scoped] Load early preload.php on scoped bootstrap.php on phpunit running

* ensure verify Node interface exists

* handling on phpunit 12.+ only

* final touch: better note example use of phpstan/phpdoc-parser that conflict can be early

* final touch: better note example use of phpstan/phpdoc-parser that conflict can be early

Author: samsonasik

build/target-repository/bootstrap.php

@@ -1,6 +1,31 @@
 <?php
 
-declare(strict_types = 1);
+declare(strict_types=1);
+
+use PHPParser\Node;
+use PHPUnit\Runner\Version;
+
+/**
+ * The preload.php contains 2 dependencies
+ *      - phpstan/phpdoc-parser
+ *      - nikic/php-parser
+ *
+ * They need to be loaded early to avoid conflict version between rector prefixed vendor and Project vendor
+ * For example, a project may use phpstan/phpdoc-parser v1, while rector uses phpstan/phpdoc-parser uses v2, that will error as class or logic are different.
+ */
+if (
+    // verify PHPUnit is running
+    defined('PHPUNIT_COMPOSER_INSTALL')
+
+    // no need to preload if Node interface exists
+    && ! interface_exists(Node::class, false)
+
+    // ensure force autoload version with class_exists() with true argument as not yet loaded
+    // for phpunit 12+ only
+    && class_exists(Version::class, true) && (int) Version::id() >= 12
+) {
+    require_once __DIR__ . '/preload.php';
+}
 
 // inspired by https://github.com/phpstan/phpstan/blob/master/bootstrap.php
 spl_autoload_register(function (string $class): void {