Fix PHPStan test

BaseHandler.php

@@ -117,7 +117,7 @@ abstract class BaseHandler implements BaseHandlerInterface {
   /**
    * {@inheritdoc}
    */
-  public function setEvent(Event $event): self {
+  public function setEvent(Event $event): BaseHandlerInterface {
     $this->event = $event;
     return $this;
   }
@@ -125,7 +125,7 @@ abstract class BaseHandler implements BaseHandlerInterface {
   /**
    * {@inheritdoc}
    */
-  public function setInput(InputInterface $input): BaseHandler {
+  public function setInput(InputInterface $input): BaseHandlerInterface {
     $this->consoleInput = $input;
     return $this;
   }

BaseHandlerInterface.php

@@ -26,16 +26,22 @@ interface BaseHandlerInterface {
    *
    * @param \Composer\Script\Event $event
    *   The composer event.
+   * 
+   * @return self
+   *   This hanlder.
    */
-  public function setEvent(Event $event);
+  public function setEvent(Event $event): BaseHandlerInterface;
 
   /**
    * Sets the input handler.
    *
    * @param \Symfony\Component\Console\Input\InputInterface $input
    *   The input handler.
+   *
+   * @return self
+   *    This hanlder.
    */
-  public function setInput(InputInterface $input);
+  public function setInput(InputInterface $input): BaseHandlerInterface;
 
   /**
    * Look up the Drupal core package object.
@@ -88,7 +94,7 @@ interface BaseHandlerInterface {
    * @param string|null $path
    *   Optional path into which to chdir before executing command.
    */
-  public function git(string $command, string $path = NULL);
+  public function git(string $command, string $path = NULL): void;
 
   /**
    * Add the given pattern to gitignore if necessary.
@@ -96,7 +102,7 @@ interface BaseHandlerInterface {
    * @param string $pattern
    *   The pattern which should be ignored.
    */
-  public function gitIgnore(string $pattern);
+  public function gitIgnore(string $pattern): void;
 
   /**
    * Add the given pattern to git lfs if necessary.
@@ -104,6 +110,6 @@ interface BaseHandlerInterface {
    * @param string $pattern
    *   The pattern which should be added.
    */
-  public function gitLfs(string $pattern);
+  public function gitLfs(string $pattern): void;
 
 }