From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 23341 invoked by alias); 18 Jun 2018 18:25:37 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 23325 invoked by uid 89); 18 Jun 2018 18:25:36 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.2 spammy= X-HELO: mail-qt0-f179.google.com X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:openpgp:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=eazcPMj+ray8cYVVGgcUG5lWdXvIPvVBTi1l89TU6K0=; b=rvmCVXlGb27X0qxD2RZ+y195Mo6EYSE1WTBo95LrQbIpPNKY/vKZ0xpfYsu0Qp0MFO 4C+E5b8ydq7RJO6gn0X7JjVldbBf2sa0s78ikwl5rWfjwrMIveV4Md7t5YF98MwEY1V6 IQ15UswHk62jSgSdIQctDGbym/9grH4m/Itg1bEdSzphQYVW26RJjZ1Fb/zBHw+z/CzE hlnYtTEdV0z6+8I3rMmz1vKnDjIOWCGwLjRqr++6H77nTHCgei9gSllHnlllm6cXUqd+ SdvQTdu+LlE4cEgx69MmZoq3BuA/Bh9VYZWvIOmHe7yR1woTOHfMDtYn2I0bNinJQ0Vx LO7w== X-Gm-Message-State: APt69E0B/ZvL9djFzjwyp9SwvKo3DlqBGF/XdJUPuDvMm3v6UdwM8JIk Hu8mBbIp46MYT1i027u+nGceZVHHFVw= X-Google-Smtp-Source: ADUXVKL+4JpAVvoEmtYgE2XdCEBw4SVrj+lPDAyGy7LJ82nxYMr1IFL8iXu+Kf/WjtkFbNpkVxN0aA== X-Received: by 2002:ac8:19ca:: with SMTP id s10-v6mr11780929qtk.303.1529346333309; Mon, 18 Jun 2018 11:25:33 -0700 (PDT) Subject: Re: Future of libio vtable compatibility To: libc-alpha@sourceware.org References: <87h8m41oa0.fsf@mid.deneb.enyo.de> <3a215566-1748-a095-8bfa-c5c1d5017156@redhat.com> <874li0uig3.fsf@mid.deneb.enyo.de> From: Adhemerval Zanella Openpgp: preference=signencrypt Message-ID: <59a4b90c-4a7f-802e-8e5a-407dccbeade4@linaro.org> Date: Mon, 18 Jun 2018 18:25:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-SW-Source: 2018-06/txt/msg00512.txt.bz2 On 18/06/2018 14:41, Zack Weinberg wrote: > On Mon, Jun 18, 2018 at 1:13 PM, Florian Weimer wrote: >> >> We could require that vtable compatibility requires setting an >> environment variable in glibc 2.28. This might finally allow us to >> gather some data. Either nobody needs backwards compatibility, or our >> backwards compatibility is just too perfect. It's difficult to tell >> why we don't see more bug reports in this area. > > This is not quite the same thing as vtable compatibility, but based on > having had to read a bunch of the relevant code for the bits/types/ > work, I suspect that programs that require the "old" FILE struct have > been broken for some time. > > zw > I do think the libio compatibility is really more a burden than a solution. If I recall correctly, we already have it broken in some occasions (for instance [1]) to fix actual reported bugs. And I think it is quite unproductive to keep compatibility to quite broken API which does not seem to used anywhere and which requires an extra burden in both testing and development for the sake of compatibility (which we can't effectively test by the way). [1] https://sourceware.org/ml/libc-alpha/2017-04/msg00356.html