Fix #2773: InvalidStateError on two data_received() calls

CHANGES.rst

@@ -14,6 +14,12 @@ Changelog
 
 .. towncrier release notes start
 
+3.0.5 (2018-02-27)
+==================
+
+- Fix ``InvalidStateError`` on processing a seria of two consequenced
+  ``RequestHandler.data_received`` calls on web server. (#2773)
+
 3.0.4 (2018-02-26)
 ==================
 

aiohttp/web_protocol.py

@@ -250,8 +250,11 @@ def data_received(self, data):
                         self._request_count += 1
                         self._messages.append((msg, payload))
 
-                    if self._waiter is not None:
-                        self._waiter.set_result(None)
+                    waiter = self._waiter
+                    if waiter is not None:
+                        if not waiter.done():
+                            # don't set result twice
+                            waiter.set_result(None)
 
                 self._upgraded = upgraded
                 if upgraded and tail:

tests/test_web_protocol.py

@@ -797,3 +797,23 @@ def test__process_keepalive_force_close(loop, srv):
     with mock.patch.object(loop, "call_at") as call_at_patched:
         srv._process_keepalive()
         assert not call_at_patched.called
+
+
+def test_two_data_received_without_waking_up_start_task(srv, loop):
+    # make a chance to srv.start() method start waiting for srv._waiter
+    loop.run_until_complete(asyncio.sleep(0.01))
+    assert srv._waiter is not None
+
+    srv.data_received(
+        b'GET / HTTP/1.1\r\n'
+        b'Host: ex.com\r\n'
+        b'Content-Length: 1\r\n\r\n'
+        b'a')
+    srv.data_received(
+        b'GET / HTTP/1.1\r\n'
+        b'Host: ex.com\r\n'
+        b'Content-Length: 1\r\n\r\n'
+        b'b')
+
+    assert len(srv._messages) == 2
+    assert srv._waiter.done()