From mboxrd@z Thu Jan 1 00:00:00 1970 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 C6CB0ECAAA3 for ; Fri, 26 Aug 2022 07:10:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245214AbiHZHKo (ORCPT ); Fri, 26 Aug 2022 03:10:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33266 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245215AbiHZHKj (ORCPT ); Fri, 26 Aug 2022 03:10:39 -0400 Received: from cloud.peff.net (cloud.peff.net [104.130.231.41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B5C5DF32 for ; Fri, 26 Aug 2022 00:10:34 -0700 (PDT) Received: (qmail 17990 invoked by uid 109); 26 Aug 2022 07:10:33 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with ESMTP; Fri, 26 Aug 2022 07:10:33 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 4358 invoked by uid 111); 26 Aug 2022 07:10:35 -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; Fri, 26 Aug 2022 03:10:35 -0400 Authentication-Results: peff.net; auth=none Date: Fri, 26 Aug 2022 03:10:32 -0400 From: Jeff King To: =?utf-8?B?w4Z2YXIgQXJuZmrDtnLDsA==?= Bjarmason Cc: Derrick Stolee , git@vger.kernel.org Subject: Re: [PATCH 0/11] annotating unused function parameters Message-ID: References: <220819.861qtc8gug.gmgdl@evledraar.gmail.com> <220819.868rnk54ju.gmgdl@evledraar.gmail.com> <220825.86edx44lzh.gmgdl@evledraar.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <220825.86edx44lzh.gmgdl@evledraar.gmail.com> Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Thu, Aug 25, 2022 at 01:00:19PM +0200, Ævar Arnfjörð Bjarmason wrote: > > One, it feels like we're abusing the deprecated attribute here. The > > Definitely, but structurally it seems like a better pick. I.e. isn't the > only problem with it the "deprecated" and its interaction with > -Wno-deprecated. > > If the exact same feature existed as a "insert-custom-warning", which > would work exactly "deprecated" without the default warning "prefix" > would you think this would fit perfectly? Yeah, I agree that would remove my complaint about overloading the meaning. I don't think that exists, though. > This is mildly annoying, but I don't really think it's a practical > issue. We're talking about running this without > -Wno-deprecated-declarations in CI, and by default. > > For unused parameters it's enough that we're catching them somewhere, or > in common compilation settings, we don't need to catch them > *everywhere*, do we? No, but the farther away you go from the edit-compile-run cycle, the more painful warnings become. Catching them immediately and fully has real value, as it means the cost of correcting them is lower. So all things being equal, I think we should prefer universal solutions when they're available (and for example compiler errors over say, coccinelle or other analysis tools). (And yes, I know all things sadly aren't equal; see below...) > IOW is anyone writing patches where they're testing with > -Wno-deprecated-declarations *and* adding unused parameters *and* won't > test without -Wno-deprecated-declarations before submitting them, *and* > nobody else will catch it? Probably not. I don't actually build with -Wno-deprecated-declarations routinely. But my fear is that some platform may be stuck there for a while (because an overzealous libc marks something). But that's kind of hypothetical, so we may have to just accept it and cross that bridge if we come to it. > > And finally, I actually prefer the parentheses of: > > > > static int register_ref(const char *refname, const struct object_id *oid, > > int UNUSED(flags), void *UNUSED(cb_data)) > > ...and now to the real reason for the follow-up. You/Junio were CC'd, > but this is breaking coccinelle, see: > https://lore.kernel.org/git/220825.86ilmg4mil.gmgdl@evledraar.gmail.com/ Ugh. Yeah, that is really unfortunate. I much prefer the parenthesized syntax, but if we can't find a way to unconfuse third-party parsing, then switching is probably the least-bad solution. -Peff