[ci] add simple script to detect duplicated short class names

Author: TomasVotruba

scripts/unique-rector-short-class-name.php

@@ -0,0 +1,47 @@
+<?php
+
+// this is part of downgrade build
+
+declare(strict_types=1);
+
+require __DIR__ . '/../vendor/autoload.php';
+
+$rectorClassFinder = new \Rector\Scripts\Finder\RectorClassFinder();
+$rectorClassNames = $rectorClassFinder->find([
+    __DIR__ . '/../src',
+    __DIR__ . '/../rules',
+    __DIR__ . '/../vendor/rector/rector-doctrine',
+    __DIR__ . '/../vendor/rector/rector-phpunit',
+    __DIR__ . '/../vendor/rector/rector-symfony',
+    __DIR__ . '/../vendor/rector/rector-downgrade-php',
+]);
+
+$shortClassNames = [];
+foreach ($rectorClassNames as $rectorClassName) {
+    $shortClassNames[] = substr($rectorClassName, strrpos($rectorClassName, '\\') + 1);
+}
+
+$classNamesToCounts = array_count_values($shortClassNames);
+$duplicatedShortClassNames = [];
+
+foreach ($classNamesToCounts as $className => $count) {
+    if ($count === 1) {
+        // unique, skip
+        continue;
+    }
+
+    $duplicatedShortClassNames[] = $className;
+}
+
+if ($duplicatedShortClassNames === []) {
+    // good
+    echo "All Rector class names are unique!\n";
+    exit(\Rector\Console\ExitCode::SUCCESS);
+}
+
+echo "The following Rector class names are duplicated:\n";
+foreach ($duplicatedShortClassNames as $duplicatedShortClassName) {
+    echo sprintf("- %s\n", $duplicatedShortClassName);
+}
+
+exit(\Rector\Console\ExitCode::FAILURE);