greenio: _recv_loop behaviour with recv_into on closed sock

make sure `_recv_loop` returns the correct value when `recv_meth` is of
foo_into type (fills a buffer and returns number of bytes, not the data)

https://github.com/eventlet/eventlet/pull/353
https://github.com/onefinestay/nameko/issues/368

eventlet/greenio/base.py

@@ -318,7 +318,7 @@ class GreenSocket(object):
             timeout=self.gettimeout(),
             timeout_exc=socket.timeout("timed out"))
 
-    def _recv_loop(self, recv_meth, *args):
+    def _recv_loop(self, recv_meth, empty_val, *args):
         fd = self.fd
         if self.act_non_blocking:
             return recv_meth(*args)
@@ -340,7 +340,7 @@ class GreenSocket(object):
                 if get_errno(e) in SOCKET_BLOCKING:
                     pass
                 elif get_errno(e) in SOCKET_CLOSED:
-                    return b''
+                    return empty_val
                 else:
                     raise
 
@@ -351,16 +351,16 @@ class GreenSocket(object):
                 raise EOFError()
 
     def recv(self, bufsize, flags=0):
-        return self._recv_loop(self.fd.recv, bufsize, flags)
+        return self._recv_loop(self.fd.recv, b'', bufsize, flags)
 
     def recvfrom(self, bufsize, flags=0):
-        return self._recv_loop(self.fd.recvfrom, bufsize, flags)
+        return self._recv_loop(self.fd.recvfrom, b'', bufsize, flags)
 
     def recv_into(self, buffer, nbytes=0, flags=0):
-        return self._recv_loop(self.fd.recv_into, buffer, nbytes, flags)
+        return self._recv_loop(self.fd.recv_into, 0, buffer, nbytes, flags)
 
     def recvfrom_into(self, buffer, nbytes=0, flags=0):
-        return self._recv_loop(self.fd.recvfrom_into, buffer, nbytes, flags)
+        return self._recv_loop(self.fd.recvfrom_into, 0, buffer, nbytes, flags)
 
     def _send_loop(self, send_method, data, *args):
         if self.act_non_blocking:

tests/socket_test.py

@@ -1,3 +1,4 @@
+import array
 import os
 import shutil
 import sys
@@ -37,6 +38,27 @@ def test_recv_type():
     assert isinstance(s, bytes)
 
 
+def test_recv_into_type():
+    # make sure `_recv_loop` returns the correct value when `recv_meth` is of
+    # foo_into type (fills a buffer and returns number of bytes, not the data)
+    # Using threads like `test_recv_type` above.
+    threading = eventlet.patcher.original('threading')
+    addr = []
+
+    def server():
+        sock = eventlet.listen(('127.0.0.1', 0))
+        addr[:] = sock.getsockname()
+        eventlet.sleep(0.2)
+
+    server_thread = threading.Thread(target=server)
+    server_thread.start()
+    eventlet.sleep(0.1)
+    sock = eventlet.connect(tuple(addr))
+    buf = array.array('B', b' ')
+    res = sock.recv_into(buf, 1)
+    assert isinstance(res, int)
+
+
 def test_dns_methods_are_green():
     assert socket.gethostbyname is greendns.gethostbyname
     assert socket.gethostbyname_ex is greendns.gethostbyname_ex