Merged revisions 84814 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k

........
  r84814 | antoine.pitrou | 2010-09-14 20:37:24 +0200 (mar., 14 sept. 2010) | 4 lines

  Issue #9854: The default read() implementation in io.RawIOBase now
  handles non-blocking readinto() returning None correctly.
........
diff --git a/Lib/_pyio.py b/Lib/_pyio.py
index ffbfda1..4485233 100644
--- a/Lib/_pyio.py
+++ b/Lib/_pyio.py
@@ -542,6 +542,8 @@
             return self.readall()
         b = bytearray(n.__index__())
         n = self.readinto(b)
+        if n is None:
+            return None
         del b[n:]
         return bytes(b)
 
@@ -559,7 +561,7 @@
         """Read up to len(b) bytes into b.
 
         Returns number of bytes read (0 for EOF), or None if the object
-        is set not to block as has no data to read.
+        is set not to block and has no data to read.
         """
         self._unsupported("readinto")