Make LoaderInterface::load() $source parameter optional

src/store/src/Document/Loader/InMemoryLoader.php

@@ -30,7 +30,7 @@ public function __construct(
     ) {
     }
 
-    public function load(?string $source, array $options = []): iterable
+    public function load(?string $source = null, array $options = []): iterable
     {
         yield from $this->documents;
     }

src/store/src/Document/Loader/RssFeedLoader.php

@@ -41,7 +41,7 @@ public function __construct(
     /**
      * @param array{uuid_namespace?: string} $options
      */
-    public function load(?string $source, array $options = []): iterable
+    public function load(?string $source = null, array $options = []): iterable
     {
         if (!class_exists(Crawler::class)) {
             throw new RuntimeException('For using the RSS loader, the Symfony DomCrawler component is required. Try running "composer require symfony/dom-crawler".');

src/store/src/Document/Loader/TextFileLoader.php

@@ -23,7 +23,7 @@
  */
 final class TextFileLoader implements LoaderInterface
 {
-    public function load(?string $source, array $options = []): iterable
+    public function load(?string $source = null, array $options = []): iterable
     {
         if (null === $source) {
             throw new InvalidArgumentException('TextFileLoader requires a file path as source, null given.');

src/store/src/Document/LoaderInterface.php

@@ -22,5 +22,5 @@ interface LoaderInterface
      *
      * @return iterable<EmbeddableDocumentInterface> iterable of embeddable documents loaded from the source
      */
-    public function load(?string $source, array $options = []): iterable;
+    public function load(?string $source = null, array $options = []): iterable;
 }