From: Junio C Hamano <gitster@pobox.com>
To: git@vger.kernel.org
Subject: [PATCH] cocci: remove risky "if (!E) free(E)" conversion
Date: Fri, 11 Sep 2026 15:09:47 -0700 [thread overview]
Message-ID: <xmqqld978mok.fsf@gitster.g> (raw)
The current cocci patches try to convert
if (!E)
free(E);
into an unconditional call to free(E), with the rationale
cocci: detect useless free(3) calls
Add a semantic patch for removing checks that cause free(3) to only be
called with a NULL pointer, as that must be a programming mistake.
which came from ec6cd14c7a (cocci: detect useless free(3) calls,
2017-02-11).
Leaving _something_ in ALL.patch output to draw programmers'
attention is a good thing, but this changes a piece of code that is
originally a no-op to do something else, which may be even worse.
We could change it to
if (!E)
BUG("free(E) is certainly not what we meant to write");
to force programmers to think. But it probably is safer to just
rewrite one form of no-op into a simpler form of no-op.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
tools/coccinelle/free.cocci | 10 ----------
1 file changed, 10 deletions(-)
diff --git a/tools/coccinelle/free.cocci b/tools/coccinelle/free.cocci
index 03799e1908..3dfaae9dd8 100644
--- a/tools/coccinelle/free.cocci
+++ b/tools/coccinelle/free.cocci
@@ -8,16 +8,6 @@ expression E;
commit_list_free(E);
)
-@@
-expression E;
-@@
-- if (!E)
-(
- free(E);
-|
- commit_list_free(E);
-)
-
@@
expression E;
@@
--
2.56.0-rc0-143-g1fea62d0ca
next reply other threads:[~2026-09-11 22:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-11 22:09 Junio C Hamano [this message]
2026-09-11 22:21 ` [PATCH] cocci: FREE_AND_NULL(E) is safe to call on NULL Junio C Hamano
2026-09-12 7:13 ` [PATCH] cocci: remove risky "if (!E) free(E)" conversion René Scharfe
2026-09-12 19:07 ` Junio C Hamano
2026-09-13 10:45 ` René Scharfe
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