Re: [libvirt] [PATCH] don't test "res == NULL" after we've already dereferenced it

On Wed, Jan 06, 2010 at 12:46:11PM +0100, Jim Meyering wrote: > As the log says, once we've dereferenced it, > there's no point in comparing to NULL. > > >From 463eaf1027a154e71839a67eca85b3ada8b817ff Mon Sep 17 00:00:00 2001 > From: Jim Meyering <meyering(a)redhat.com&gt; > Date: Wed, 6 Jan 2010 12:45:07 +0100 > Subject: [PATCH] don't test "res == NULL" after we've already dereferenced it > > * src/xen/proxy_internal.c (xenProxyCommand): It is known to be > non-NULL at that point, so remove the "ret == NULL" guard, and > instead add an assert(ret != NULL), in case future code changes > cause the condition to becomes false. > Include <assert.h>. > --- > src/xen/proxy_internal.c | 6 ++++-- > 1 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/src/xen/proxy_internal.c b/src/xen/proxy_internal.c > index ec4522b..42b6e91 100644 > --- a/src/xen/proxy_internal.c > +++ b/src/xen/proxy_internal.c > @@ -1,7 +1,7 @@ > /* > * proxy_client.c: client side of the communication with the libvirt proxy. > * > - * Copyright (C) 2006, 2008, 2009 Red Hat, Inc. > + * Copyright (C) 2006, 2008, 2009, 2010 Red Hat, Inc. > * > * See COPYING.LIB for the License of this software > * > @@ -11,6 +11,7 @@ > #include <config.h> > > #include <stdio.h> > +#include <assert.h> > #include <stdlib.h> > #include <unistd.h> > #include <errno.h> > @@ -444,7 +445,8 @@ retry: > /* > * do more checks on the incoming packet. > */ > - if ((res == NULL) || (res->version != PROXY_PROTO_VERSION) || > + assert (res != NULL); > + if ((res->version != PROXY_PROTO_VERSION) || > (res->len < sizeof(virProxyPacket))) { > virProxyError(conn, VIR_ERR_INTERNAL_ERROR, "%s", > _("Communication error with proxy: malformed packet\n")); I'm not too fond of adding an assert, res should not be null there or we should already have crashed. ACK to the change without the new assert line.