Throw exception for graphql errors

lib/Github/HttpClient/Plugin/GithubExceptionThrower.php

@@ -29,6 +29,8 @@ public function doHandleRequest(RequestInterface $request, callable $next, calla
     {
         return $next($request)->then(function (ResponseInterface $response) use ($request) {
             if ($response->getStatusCode() < 400 || $response->getStatusCode() > 600) {
+                $this->checkGraphqlErrors($response);
+
                 return $response;
             }
 
@@ -117,4 +119,38 @@ public function doHandleRequest(RequestInterface $request, callable $next, calla
             throw new RuntimeException(isset($content['message']) ? $content['message'] : $content, $response->getStatusCode());
         });
     }
+
+    /**
+     * The graphql api doesn't return a 5xx http status for errors. Instead it returns a 200 with an error body.
+     *
+     * @throws RuntimeException
+     */
+    private function checkGraphqlErrors(ResponseInterface $response): void
+    {
+        if ($response->getStatusCode() !== 200) {
+            return;
+        }
+
+        $content = ResponseMediator::getContent($response);
+        if (!is_array($content)) {
+            return;
+        }
+
+        if (!isset($content['errors']) || !is_array($content['errors'])) {
+            return;
+        }
+
+        $errors = [];
+        foreach ($content['errors'] as $error) {
+            if (isset($error['message'])) {
+                $errors[] = $error['message'];
+            }
+        }
+
+        if (empty($errors)) {
+            return;
+        }
+
+        throw new RuntimeException(implode(', ', $errors));
+    }
 }

test/Github/Tests/HttpClient/Plugin/GithubExceptionThrowerTest.php

@@ -154,6 +154,29 @@ public static function responseProvider()
                 ),
                 'exception' => new \Github\Exception\RuntimeException('Error message', 555),
             ],
+            'Graphql error response (200)' => [
+                'response' => new Response(
+                    200,
+                    [
+                        'content-type' => 'application/json',
+                    ],
+                    json_encode(
+                        [
+                            'errors' => [
+                                [
+                                    ['path' => ['query', 'repository']],
+                                    'message' => 'Field "xxxx" doesn\'t exist on type "Issue"',
+                                ],
+                                [
+                                    ['path' => ['query', 'repository']],
+                                    'message' => 'Field "dummy" doesn\'t exist on type "PullRequest"',
+                                ],
+                            ],
+                        ]
+                    )
+                ),
+                'exception' => new \Github\Exception\RuntimeException('Field "xxxx" doesn\'t exist on type "Issue", Field "dummy" doesn\'t exist on type "PullRequest"'),
+            ],
         ];
     }
 }