#1389051, #1092502: fix excessively large allocations when using read() on a socket

Lib/socket.py

@@ -305,7 +305,7 @@ class _fileobject(object):
             self._rbuf = ""
             while True:
                 left = size - buf_len
-                recv_size = max(self._rbufsize, left)
+                recv_size = min(self._rbufsize, left)
                 data = self._sock.recv(recv_size)
                 if not data:
                     break

Misc/NEWS

@@ -18,6 +18,9 @@ Library
 - Bug #1389051: imaplib causes excessive memory fragmentation when reading
   large messages.
 
+- Bug #1389051, 1092502: fix excessively large memory allocations when
+  calling .read() on a socket object wrapped with makefile(). 
+
 - Bug #1433694: minidom's .normalize() failed to set .nextSibling for
   last child element.