Support Guzzle 7+

src/Strategy/CommonClassesStrategy.php

@@ -26,6 +26,7 @@
 use Http\Message\StreamFactory\SlimStreamFactory;
 use Http\Message\UriFactory\SlimUriFactory;
 use Slim\Http\Request as SlimRequest;
+use GuzzleHttp\Client as GuzzleHttp;
 use Http\Adapter\Guzzle6\Client as Guzzle6;
 use Http\Adapter\Guzzle5\Client as Guzzle5;
 use Http\Client\Curl\Client as Curl;
@@ -95,6 +96,10 @@ final class CommonClassesStrategy implements DiscoveryStrategy
                 'class' => [self::class, 'symfonyPsr18Instantiate'],
                 'condition' => [SymfonyPsr18::class, Psr17RequestFactory::class],
             ],
+            [
+                'class' => GuzzleHttp::class,
+                'condition' => GuzzleHttp::class,
+            ],
             [
                 'class' => [self::class, 'buzzInstantiate'],
                 'condition' => [\Buzz\Client\FileGetContents::class, \Buzz\Message\ResponseBuilder::class],
@@ -107,9 +112,20 @@ final class CommonClassesStrategy implements DiscoveryStrategy
      */
     public static function getCandidates($type)
     {
-        if (Psr18Client::class === $type) {
-            $candidates = self::$classes[PSR18Client::class];
+        $candidates = [];
 
+        foreach (self::$classes[$type] ?? [] as $c) {
+            // Guzzle 6 does not implement the PSR-18 client interface, but Guzzle 7 does.
+            if (Psr18Client::class === $type && GuzzleHttp::class === $c['class']) {
+                if (defined('GuzzleHttp\ClientInterface::MAJOR_VERSION')) {
+                    $candidates[] = $c;
+                }
+            } else {
+                $candidates[] = $c;
+            }
+        }
+
+        if (Psr18Client::class === $type) {
             // HTTPlug 2.0 clients implements PSR18Client too.
             foreach (self::$classes[HttpClient::class] as $c) {
                 try {
@@ -120,15 +136,9 @@ public static function getCandidates($type)
                     trigger_error(sprintf('Got exception "%s (%s)" while checking if a PSR-18 Client is available', get_class($e), $e->getMessage()), E_USER_WARNING);
                 }
             }
-
-            return $candidates;
-        }
-
-        if (isset(self::$classes[$type])) {
-            return self::$classes[$type];
         }
 
-        return [];
+        return $candidates;
     }
 
     public static function buzzInstantiate()