Adding Rector to ease backporting to PHP7.4

Author: nyamsprod

Makefile

@@ -22,8 +22,12 @@ phpcs:
 test:
 	@docker run --rm -it -v$(PWD):/app composer test
 
-# test
+# downgrade
+downgrade:
+	@docker run --rm -it -v$(PWD):/app --workdir=/app php:8.1-cli-alpine vendor/bin/rector process src
+
+# sandbox
 sandbox:
 	@docker run --rm -it -v$(PWD):/app php:8.1-cli-alpine php ./app/test.php
 
-.PHONY: install update phpunit phpstan phpcs test
+.PHONY: install update phpunit phpstan phpcs test sandbox downgrade

composer.json

@@ -34,7 +34,8 @@
         "phpstan/phpstan-strict-rules": "^1.1",
         "phpstan/phpstan-phpunit": "^1.0",
         "phpstan/phpstan-deprecation-rules": "^1.0",
-        "phpunit/phpunit": "^9.5.20"
+        "phpunit/phpunit": "^9.5.20",
+        "rector/rector": "~0.12.21"
     },
     "autoload": {
         "psr-4": {

rector.php

@@ -0,0 +1,51 @@
+<?php 
+
+declare(strict_types=1);
+
+use Rector\Core\Configuration\Option;
+use Rector\DowngradePhp74\Rector\Coalesce\DowngradeNullCoalescingOperatorRector;
+use Rector\DowngradePhp74\Rector\ArrowFunction\ArrowFunctionToAnonymousFunctionRector;
+use Rector\DowngradePhp74\Rector\Property\DowngradeTypedPropertyRector;
+use Rector\DowngradePhp80\Rector\Catch_\DowngradeNonCapturingCatchesRector;
+use Rector\DowngradePhp80\Rector\Class_\DowngradePropertyPromotionRector;
+use Rector\DowngradePhp80\Rector\ClassMethod\DowngradeTrailingCommasInParamUseRector;
+use Rector\DowngradePhp80\Rector\FunctionLike\DowngradeUnionTypeDeclarationRector;
+use Rector\DowngradePhp80\Rector\Property\DowngradeUnionTypeTypedPropertyRector;
+use Rector\DowngradePhp80\Rector\NullsafeMethodCall\DowngradeNullsafeToTernaryOperatorRector;
+use Rector\DowngradePhp80\Rector\ClassMethod\DowngradeStaticTypeDeclarationRector;
+use Rector\DowngradePhp80\Rector\FuncCall\DowngradeStrContainsRector;
+use Rector\DowngradePhp80\Rector\Expression\DowngradeThrowExprRector;
+use Rector\DowngradePhp81\Rector\FuncCall\DowngradeArrayIsListRector;
+use Rector\DowngradePhp81\Rector\Array_\DowngradeArraySpreadStringKeyRector;
+use Rector\DowngradePhp81\Rector\FuncCall\DowngradeFirstClassCallableSyntaxRector;
+use Rector\DowngradePhp81\Rector\FunctionLike\DowngradeNewInInitializerRector;
+use Rector\DowngradePhp81\Rector\Property\DowngradeReadonlyPropertyRector;
+use Rector\DowngradePhp80\Rector\Expression\DowngradeMatchToSwitchRector;
+
+use Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;
+
+return static function (ContainerConfigurator $containerConfigurator): void {
+
+	$parameters = $containerConfigurator->parameters();
+
+	$parameters->set(Option::PATHS, __DIR__.'/src');
+	$parameters->set(Option::PHP_VERSION_FEATURES, 70400);
+
+	$services = $containerConfigurator->services();
+
+    $services->set(DowngradeTrailingCommasInParamUseRector::class);
+    $services->set(DowngradeNonCapturingCatchesRector::class);
+    $services->set(DowngradeUnionTypeTypedPropertyRector::class);
+    $services->set(DowngradePropertyPromotionRector::class);
+    $services->set(DowngradeUnionTypeDeclarationRector::class);
+    $services->set(DowngradeNullsafeToTernaryOperatorRector::class);
+    $services->set(DowngradeStaticTypeDeclarationRector::class);
+    $services->set(DowngradeStrContainsRector::class);
+    $services->set(DowngradeThrowExprRector::class);
+    $services->set(DowngradeArrayIsListRector::class);
+    $services->set(DowngradeArraySpreadStringKeyRector::class);
+    $services->set(DowngradeFirstClassCallableSyntaxRector::class);
+    $services->set(DowngradeNewInInitializerRector::class);
+    $services->set(DowngradeReadonlyPropertyRector::class);
+    $services->set(DowngradeMatchToSwitchRector::class);
+};