From patchwork Thu Aug 31 21:22:15 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff King X-Patchwork-Id: 13371879 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 09546C83F2F for ; Thu, 31 Aug 2023 21:23:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245437AbjHaVXD (ORCPT ); Thu, 31 Aug 2023 17:23:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44620 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343610AbjHaVXA (ORCPT ); Thu, 31 Aug 2023 17:23:00 -0400 Received: from cloud.peff.net (cloud.peff.net [104.130.231.41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9C2E210D1 for ; Thu, 31 Aug 2023 14:22:23 -0700 (PDT) Received: (qmail 26031 invoked by uid 109); 31 Aug 2023 21:22:16 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with ESMTP; Thu, 31 Aug 2023 21:22:16 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 11613 invoked by uid 111); 31 Aug 2023 21:22:16 -0000 Received: from coredump.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.2) by peff.net (qpsmtpd/0.94) with (TLS_AES_256_GCM_SHA384 encrypted) ESMTPS; Thu, 31 Aug 2023 17:22:16 -0400 Authentication-Results: peff.net; auth=none Date: Thu, 31 Aug 2023 17:22:15 -0400 From: Jeff King To: git@vger.kernel.org Cc: Junio C Hamano , =?utf-8?b?UmVuw6k=?= Scharfe Subject: [PATCH v2 09/10] interpret-trailers: mark unused "unset" parameters in option callbacks Message-ID: <20230831212215.GI949469@coredump.intra.peff.net> References: <20230831211637.GA949188@coredump.intra.peff.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20230831211637.GA949188@coredump.intra.peff.net> Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org There are a few parse-option callbacks that do not look at their "unset" parameters, but also do not set PARSE_OPT_NONEG. At first glance this seems like a bug, as we'd ignore "--no-if-exists", etc. But they do work fine, because when "unset" is true, then "arg" is NULL. And all three functions pass "arg" on to helper functions which do the right thing with the NULL. Note that this shortcut would not be correct if any callback used PARSE_OPT_NOARG (in which case "arg" would be NULL but "unset" would be false). But none of these do. So the code is fine as-is. But we'll want to mark the unused "unset" parameters to quiet -Wunused-parameter. I've also added a comment to make this rather subtle situation more explicit. Signed-off-by: Jeff King --- I looked at another BUG_ON here, but it was just so ugly and one-off that I preferred just adding the comments. builtin/interpret-trailers.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/builtin/interpret-trailers.c b/builtin/interpret-trailers.c index 6aadce6a1e..a110e69f83 100644 --- a/builtin/interpret-trailers.c +++ b/builtin/interpret-trailers.c @@ -24,20 +24,23 @@ static enum trailer_if_exists if_exists; static enum trailer_if_missing if_missing; static int option_parse_where(const struct option *opt, - const char *arg, int unset) + const char *arg, int unset UNUSED) { + /* unset implies NULL arg, which is handled in our helper */ return trailer_set_where(opt->value, arg); } static int option_parse_if_exists(const struct option *opt, - const char *arg, int unset) + const char *arg, int unset UNUSED) { + /* unset implies NULL arg, which is handled in our helper */ return trailer_set_if_exists(opt->value, arg); } static int option_parse_if_missing(const struct option *opt, - const char *arg, int unset) + const char *arg, int unset UNUSED) { + /* unset implies NULL arg, which is handled in our helper */ return trailer_set_if_missing(opt->value, arg); }