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From: Jeff King <peff@peff.net>
To: git@vger.kernel.org
Cc: Junio C Hamano <gitster@pobox.com>,
	Patrick Steinhardt <ps@pks.im>,
	Collin Funk <collin.funk1@gmail.com>,
	Michael J Gruber <git@grubix.eu>
Subject: [PATCH v2 05/12] run-command: explicitly cast away constness when assigning to void
Date: Thu, 2 Apr 2026 00:15:01 -0400	[thread overview]
Message-ID: <20260402041501.GE3501239@coredump.intra.peff.net> (raw)
In-Reply-To: <20260402041433.GA3501120@coredump.intra.peff.net>

We do this:

  char *equals = strchr(*e, '=');

which implicitly removes the constness from "*e" and cause the compiler
to complain. We never write to "equals", but later assign it to a
string_list util field, which is defined as non-const "void *".

We have to cast somewhere, but doing so at the assignment to util is the
least-bad place, since that is the source of the confusion. Sadly we are
still open to accidentally writing to the string via the util pointer,
but that is the cost of using void pointers, which lose all type
information.

Signed-off-by: Jeff King <peff@peff.net>
---
 run-command.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/run-command.c b/run-command.c
index 32c290ee6a..d6980c79b3 100644
--- a/run-command.c
+++ b/run-command.c
@@ -604,11 +604,11 @@ static void trace_add_env(struct strbuf *dst, const char *const *deltaenv)
 	/* Last one wins, see run-command.c:prep_childenv() for context */
 	for (e = deltaenv; e && *e; e++) {
 		struct strbuf key = STRBUF_INIT;
-		char *equals = strchr(*e, '=');
+		const char *equals = strchr(*e, '=');
 
 		if (equals) {
 			strbuf_add(&key, *e, equals - *e);
-			string_list_insert(&envs, key.buf)->util = equals + 1;
+			string_list_insert(&envs, key.buf)->util = (void *)(equals + 1);
 		} else {
 			string_list_insert(&envs, *e)->util = NULL;
 		}
-- 
2.53.0.1172.ge9e20b5838


  parent reply	other threads:[~2026-04-02  4:15 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-31 23:38 [PATCH 0/12] fixing the remainder of the C23 strchr warnings Jeff King
2026-03-31 23:41 ` [PATCH 01/12] convert: add const to fix strchr() warnings Jeff King
2026-03-31 23:41 ` [PATCH 02/12] http: " Jeff King
2026-03-31 23:41 ` [PATCH 03/12] transport-helper: drop " Jeff King
2026-04-01 13:46   ` Patrick Steinhardt
2026-03-31 23:42 ` [PATCH 04/12] pager: explicitly cast away strchr() constness Jeff King
2026-04-01 20:50   ` Junio C Hamano
2026-04-02  3:54     ` Jeff King
2026-03-31 23:42 ` [PATCH 05/12] run-command: explicitly cast away constness when assigning to void Jeff King
2026-03-31 23:44 ` [PATCH 06/12] find_last_dir_sep(): convert inline function to macro Jeff King
2026-03-31 23:46 ` [PATCH 07/12] pseudo-merge: fix disk reads from find_pseudo_merge() Jeff King
2026-03-31 23:56   ` Jeff King
2026-04-01 21:40     ` Junio C Hamano
2026-04-02 23:51     ` Taylor Blau
2026-03-31 23:50 ` [PATCH 08/12] skip_prefix(): check const match between in and out params Jeff King
2026-04-01 13:17   ` Phillip Wood
2026-04-01 14:04     ` Phillip Wood
2026-04-01 19:24       ` Jeff King
2026-04-01 22:13         ` Junio C Hamano
2026-04-02 15:05         ` Phillip Wood
2026-04-01 13:46   ` Patrick Steinhardt
2026-03-31 23:51 ` [PATCH 09/12] pkt-line: make packet_reader.line non-const Jeff King
2026-04-01 22:18   ` Junio C Hamano
2026-04-02  3:55     ` Jeff King
2026-03-31 23:52 ` [PATCH 10/12] range-diff: drop const to fix strstr() warnings Jeff King
2026-03-31 23:52 ` [PATCH 11/12] http: drop const to fix strstr() warning Jeff King
2026-03-31 23:53 ` [PATCH 12/12] refs/files-backend: drop const to fix strchr() warning Jeff King
2026-04-01 13:46   ` Patrick Steinhardt
2026-04-01 22:22     ` Junio C Hamano
2026-04-02  3:56       ` Jeff King
2026-04-02  4:14 ` [PATCH v2 0/12] fixing the remainder of the C23 strchr warnings Jeff King
2026-04-02  4:14   ` [PATCH v2 01/12] convert: add const to fix strchr() warnings Jeff King
2026-04-02  4:14   ` [PATCH v2 02/12] http: " Jeff King
2026-04-02  4:14   ` [PATCH v2 03/12] transport-helper: drop " Jeff King
2026-04-02  4:14   ` [PATCH v2 04/12] pager: explicitly cast away strchr() constness Jeff King
2026-04-02  4:15   ` Jeff King [this message]
2026-04-02  4:15   ` [PATCH v2 06/12] find_last_dir_sep(): convert inline function to macro Jeff King
2026-04-02  4:15   ` [PATCH v2 07/12] pseudo-merge: fix disk reads from find_pseudo_merge() Jeff King
2026-04-02  4:15   ` [PATCH v2 08/12] skip_prefix(): check const match between in and out params Jeff King
2026-04-02  5:11     ` Junio C Hamano
2026-04-02  6:01       ` Jeff King
2026-04-02 15:50         ` Junio C Hamano
2026-04-02 15:41       ` Junio C Hamano
2026-04-03 11:13     ` Toon Claes
2026-04-04  5:42       ` [PATCH v2 13/12] git-compat-util: fix CONST_OUTPARAM typo and indentation Jeff King
2026-04-02  4:15   ` [PATCH v2 09/12] pkt-line: make packet_reader.line non-const Jeff King
2026-04-02  4:15   ` [PATCH v2 10/12] range-diff: drop const to fix strstr() warnings Jeff King
2026-04-02  4:15   ` [PATCH v2 11/12] http: drop const to fix strstr() warning Jeff King
2026-04-02  4:15   ` [PATCH v2 12/12] refs/files-backend: drop const to fix strchr() warning Jeff King
2026-04-03 11:14   ` [PATCH v2 0/12] fixing the remainder of the C23 strchr warnings Toon Claes

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