Here's another example of appropriate use of assert.
The while loop removed below is currently guaranteed never
to be executed, since "list" is always NULL at that point.
However, you can argue that simply removing the loop is a little
risky: what if someone changes things to "goto cleanup" before
"list" reaches the final NULL? That's why I added the assertion:
to catch the potential (albeit unlikely) future coding error.
It would be a shame to include "real" run-time code to detect
a situation like that that will probably never arise. And if you
do, technically you'd have to document that the function would
return some sort of error code if a developer changes its guts
in a way that violates this invariant. That would be nonsensical.
>From 6baa2b0b8f9963fa60ff0946afcefd57586e2720 Mon Sep 17 00:00:00 2001
From: Jim Meyering <meyering@xxxxxxxxxx>
Date: Mon, 18 Jan 2010 10:46:57 +0100
Subject: [PATCH] secret_driver.c: remove dead cleanup code
* src/secret/secret_driver.c (loadSecrets): Remove dead code
after "cleanup:". At that point, "list" is known to be NULL.
Instead, add an assertion.
Include <assert.h>.
---
src/secret/secret_driver.c | 10 +++-------
1 files changed, 3 insertions(+), 7 deletions(-)
diff --git a/src/secret/secret_driver.c b/src/secret/secret_driver.c
index 1eef468..b4b4f8a 100644
--- a/src/secret/secret_driver.c
+++ b/src/secret/secret_driver.c
@@ -1,7 +1,7 @@
/*
* secret_driver.c: local driver for secret manipulation API
*
- * Copyright (C) 2009 Red Hat, Inc.
+ * Copyright (C) 2009-2010 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
@@ -28,6 +28,7 @@
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
+#include <assert.h>
#include "internal.h"
#include "base64.h"
@@ -518,12 +519,7 @@ loadSecrets(virConnectPtr conn, virSecretDriverStatePtr driver,
ret = 0;
cleanup:
- while (list != NULL) {
- virSecretEntryPtr s;
-
- s = listUnlink(&list);
- secretFree(s);
- }
+ assert (list == NULL);
if (dir != NULL)
closedir(dir);
return ret;
--
1.6.6.638.g2bc54
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