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

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
[off-list ref] wrote:

quoted

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