Make sure we give a nice error message if we are trying to use a clas… (#480)

* Make sure we give a nice error message if we are trying to use a class without their dependencies installed

* Typo

Author: Nyholm

src/S3FilesystemV1.php

@@ -18,6 +18,10 @@
 use League\Flysystem\Config;
 use League\Flysystem\Util;
 
+if (!class_exists(AbstractAdapter::class)) {
+    throw new \LogicException('You cannot use "AsyncAws\Flysystem\S3\S3FilesystemV1" as the "league/flysystem:1.x" package is not installed. Try running "composer require league/flysystem:^1.0".');
+}
+
 class S3FilesystemV1 extends AbstractAdapter implements CanOverwriteFiles
 {
     const PUBLIC_GRANT_URI = 'http://acs.amazonaws.com/groups/global/AllUsers';

src/S3FilesystemV2.php

@@ -31,6 +31,10 @@
 use League\MimeTypeDetection\FinfoMimeTypeDetector;
 use Throwable;
 
+if (!interface_exists(FilesystemAdapter::class)) {
+    throw new \LogicException('You cannot use "AsyncAws\Flysystem\S3\S3FilesystemV2" as the "league/flysystem:2.x" package is not installed. Try running "composer require league/flysystem:^2.0".');
+}
+
 class S3FilesystemV2 implements FilesystemAdapter
 {
     /**