Fix GraphQL integration swallowing responses (#2286)

sentry_sdk/integrations/stdlib.py

@@ -185,7 +185,9 @@ def getresponse(self, *args, **kwargs):
                     response_data = rv.read()
                     # once we've read() the body it can't be read() again by the
                     # app; save it so that it can be accessed again
-                    rv.read = io.BytesIO(response_data).read
+                    saved_response = io.BytesIO(response_data)
+                    rv.read = saved_response.read
+                    rv.fp = saved_response
                     try:
                         # py3.6+ json.loads() can deal with bytes out of the box, but
                         # for older version we have to explicitly decode first

tests/integrations/requests/test_requests.py

@@ -1,3 +1,4 @@
+import json
 import pytest
 import responses
 
@@ -7,11 +8,15 @@
 from sentry_sdk.consts import SPANDATA
 from sentry_sdk.integrations.stdlib import StdlibIntegration
 
+from tests.conftest import MockServerRequestHandler, create_mock_http_server
+
 try:
     from unittest import mock  # python 3.3 and above
 except ImportError:
     import mock  # python < 3.3
 
+PORT = create_mock_http_server()
+
 
 def test_crumb_capture(sentry_init, capture_events):
     sentry_init(integrations=[StdlibIntegration()])
@@ -62,3 +67,22 @@ def test_omit_url_data_if_parsing_fails(sentry_init, capture_events):
         "reason": response.reason,
         # no url related data
     }
+
+
+def test_graphql_integration_doesnt_affect_responses(sentry_init, capture_events):
+    sentry_init(integrations=[StdlibIntegration()])
+
+    events = capture_events()
+
+    msg = {"errors": [{"message": "some message"}]}
+
+    def do_POST(self):  # noqa: N802
+        self.send_response(200)
+        self.end_headers()
+        self.wfile.write(json.dumps(msg).encode())
+
+    with mock.patch.object(MockServerRequestHandler, "do_POST", do_POST):
+        response = requests.post("http://localhost:{}".format(PORT) + "/graphql")
+
+    assert len(events) == 1
+    assert response.json() == msg