From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI shortcircuit=no autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 080B41F597 for ; Fri, 20 Jul 2018 18:00:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388258AbeGTSuD (ORCPT ); Fri, 20 Jul 2018 14:50:03 -0400 Received: from cloud.peff.net ([104.130.231.41]:54342 "HELO cloud.peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S2387950AbeGTSuD (ORCPT ); Fri, 20 Jul 2018 14:50:03 -0400 Received: (qmail 30456 invoked by uid 109); 20 Jul 2018 18:00:41 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with SMTP; Fri, 20 Jul 2018 18:00:41 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 30304 invoked by uid 111); 20 Jul 2018 18:00:46 -0000 Received: from sigill.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.7) by peff.net (qpsmtpd/0.94) with (ECDHE-RSA-AES256-GCM-SHA384 encrypted) SMTP; Fri, 20 Jul 2018 14:00:46 -0400 Authentication-Results: peff.net; auth=none Received: by sigill.intra.peff.net (sSMTP sendmail emulation); Fri, 20 Jul 2018 14:00:39 -0400 Date: Fri, 20 Jul 2018 14:00:39 -0400 From: Jeff King To: Duy Nguyen Cc: Git Mailing List , Stefan Beller Subject: Re: [PATCH 1/2] introduce "banned function" list Message-ID: <20180720180039.GD22486@sigill.intra.peff.net> References: <20180719203259.GA7869@sigill.intra.peff.net> <20180719203901.GA8079@sigill.intra.peff.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Fri, Jul 20, 2018 at 04:41:34PM +0200, Duy Nguyen wrote: > > Let's start by banning strcpy() and sprintf(). It's not > > impossible to use these correctly, but it's easy to do so > > incorrectly, and there's always a better option. > > Is it possible to extend this to ban variables as well? I'm still > going to delete the_index from library code. Once that work is done I > will ban it from entering again (it's only allowed in builtin/ for > example). The next target after that would be the_repository. > > Right now I will do this by not declaring the variable [2], which ends > up with a much less friendly compile warning. I did something similar > [1] in an earlier iteration but did not do extensive research on this > topic like you did. IMHO just not declaring the variable is the right move (and is what I would do with these functions if libc wasn't already declaring them). The compile error may be less friendly, but these things are temporary as topics-in-flight catch up. Whereas strcpy() will be with us forever. I also think that removing variables is a special case of a larger technique: when we change function semantics, we try to change the signatures, too. So there you'll get a type error, or not enough arguments, or whatever. And the next step is usually "git log" or "git blame" to see what happened, and what the conversion should look like. -Peff