[internal] Add RelatedConfigInterface to load external services (#5605)

src/Config/RectorConfig.php

@@ -9,6 +9,7 @@
 use Rector\Configuration\Option;
 use Rector\Configuration\Parameter\SimpleParameterProvider;
 use Rector\Configuration\RectorConfigBuilder;
+use Rector\Contract\DependencyInjection\RelatedConfigInterface;
 use Rector\Contract\Rector\ConfigurableRectorInterface;
 use Rector\Contract\Rector\RectorInterface;
 use Rector\DependencyInjection\Laravel\ContainerMemento;
@@ -251,6 +252,19 @@ public function rules(array $rectorClasses): void
 
         foreach ($rectorClasses as $rectorClass) {
             $this->rule($rectorClass);
+
+            if (is_a($rectorClass, RelatedConfigInterface::class, true)) {
+                /** @var RelatedConfigInterface $rector */
+                $rector = $this->make($rectorClass);
+
+                Assert::file($rector->getConfigFile(), sprintf(
+                    'The config path "%s" in "%s::getConfigFile()" could not be found',
+                    $rector->getConfigFile(),
+                    $rector::class
+                ));
+
+                $this->import($rector->getConfigFile());
+            }
         }
     }
 

src/Contract/DependencyInjection/RelatedConfigInterface.php

@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Contract\DependencyInjection;
+
+/**
+ * @internal Use for rules that require extra custom services.
+ */
+interface RelatedConfigInterface
+{
+    public function getConfigFile(): string;
+}