Buffer objects would return the read or write buffer for a wrapped object when the char buffer was requested. Now it actually returns the char buffer if available or raises a TypeError if it isn't (as is raised for the other buffer types if they are not present but requested). Not a backport candidate since it does change semantics of the buffer object (although it could be argued this is enough of a bug to bother backporting).

--- a/Modules/arraymodule.c	Thu Jun 08 16:23:04 2006 +0000
+++ b/Modules/arraymodule.c	Thu Jun 08 17:00:45 2006 +0000
@@ -1787,6 +1787,7 @@
 	(readbufferproc)array_buffer_getreadbuf,
 	(writebufferproc)array_buffer_getwritebuf,
 	(segcountproc)array_buffer_getsegcount,
+	NULL,
 };
 
 static PyObject *