Re: [PATCH] refactor various if (x) FREE_AND_NULL(x) to just FREE_AND_NULL(x)

[Duy Nguyen <pclouds@gmail.com>]

On Fri, Aug 17, 2018 at 04:36:13PM +0200, Duy Nguyen wrote:
> On Fri, Aug 17, 2018 at 3:05 PM Ævar Arnfjörð Bjarmason
> <avarab@gmail.com> wrote:
> >
> > Change the few conditional uses of FREE_AND_NULL(x) to be
> > unconditional. As noted in the standard[1] free(NULL) is perfectly
> > valid, so we might as well leave this check up to the C library.
> 
> I'm not trying to make you work more on this. But out of curiosity
> would coccinelle help catch this pattern? Szeder's recent work on
> running cocci automatically would help catch all future code like this
> if we could write an spatch.

Just fyi this seems to do the trick. Although I'm nowhere good at
coccinelle to say if we should include this (or something like it)

-- 8< --
diff --git a/contrib/coccinelle/free.cocci b/contrib/coccinelle/free.cocci
index 4490069df9..f8e018d104 100644
--- a/contrib/coccinelle/free.cocci
+++ b/contrib/coccinelle/free.cocci
@@ -16,3 +16,9 @@ expression E;
 - free(E);
 + FREE_AND_NULL(E);
 - E = NULL;
+
+@@
+expression E;
+@@
+- if (E) { FREE_AND_NULL(E); }
++ FREE_AND_NULL(E);
-- 8< --

--
Duy