From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 41DA93858D1E for ; Thu, 18 Aug 2022 04:05:42 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 41DA93858D1E Received: from mail-qv1-f69.google.com (mail-qv1-f69.google.com [209.85.219.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-396-n-U8Cf_sPymO4ohy8NLO_w-1; Thu, 18 Aug 2022 00:05:40 -0400 X-MC-Unique: n-U8Cf_sPymO4ohy8NLO_w-1 Received: by mail-qv1-f69.google.com with SMTP id c1-20020a0cfb01000000b00495ad218c74so346886qvp.20 for ; Wed, 17 Aug 2022 21:05:40 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:organization:from:references :cc:to:content-language:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc; bh=Qeb4e+sJo6WDglE+7KuqX8R6B4BOMUDu8kGiusegf/Y=; b=7n4fCrnCZflfO14q2ZaJfgluZr2X5dPhVz2Mu/7uhBUiQZRB+Wav5+JpMl7FhQS5ry MwZVqYyY0o1NRMk7Ivyt/4cfb4elnPa6VqCIbW2F0Qcey+rOpFM3MoXx96xzIAruhB6N 01/nSQ0WiQphh5FTPwuG/3q7vPhBPPivzaec66k6kgU0ZpcIb6jEnoLwoOYxNsXG0deD X6u4Z+wE6EelHqVd2SpdMFkiVDD30cADaV3J+AE9RDGuFBQvqC6V1qLP2aPp56ZcCamj nsGkezKmvxlIdTYapsist74H8xQQ3YRSrgQ/kCM5e0l0bk6egTcERNFHaF0IYNPurSD2 /E0A== X-Gm-Message-State: ACgBeo3RIYX2RKopW61rdov8xvhvYadjGkyn85eq9xH6pWhk5+L3vnCF 62L1y9yIhkzl8vD8TAk4Pg8k5Egbj1eGBwIZkglmJT1O1hsEW4KMAFrSA7r3fVYNiWPgzSYjmv1 k7sSIlQwbYB71eTOrsZKM X-Received: by 2002:a05:6214:b6a:b0:474:90b4:f5eb with SMTP id ey10-20020a0562140b6a00b0047490b4f5ebmr986306qvb.104.1660795539754; Wed, 17 Aug 2022 21:05:39 -0700 (PDT) X-Google-Smtp-Source: AA6agR59RT7K1llhBwigtjQzj9ap0FcHE5NdLFC73heYUPbJDHM0mRJFyYJ7NHm9nY41dAJOt2xTkg== X-Received: by 2002:a05:6214:b6a:b0:474:90b4:f5eb with SMTP id ey10-20020a0562140b6a00b0047490b4f5ebmr986300qvb.104.1660795539580; Wed, 17 Aug 2022 21:05:39 -0700 (PDT) Received: from [192.168.0.241] (192-0-145-146.cpe.teksavvy.com. [192.0.145.146]) by smtp.gmail.com with ESMTPSA id h5-20020a05620a400500b006bbb07ebd83sm682769qko.108.2022.08.17.21.05.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 17 Aug 2022 21:05:38 -0700 (PDT) Message-ID: <55d6517d-5079-cde7-5934-ca3c704753b4@redhat.com> Date: Thu, 18 Aug 2022 00:05:36 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [swbz 29035] mktime vs non-DST To: Paul Eggert , DJ Delorie Cc: libc-alpha@sourceware.org References: <8c91bbc3-95cc-88d0-ffe9-5da08fcfdf38@redhat.com> From: Carlos O'Donell Organization: Red Hat In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_NONE, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 18 Aug 2022 04:05:43 -0000 On 8/17/22 23:16, Paul Eggert wrote: > On 8/17/22 19:37, Carlos O'Donell wrote: >> The mktime() interface has been around for a long time and users do >> not expect and have noticed the semantic changes we are seeing here >> today. > > The semantic changes that bother users boil down to the following: > glibc mktime returns -1 when users specify impossible is_dst flags, > whereas mktime used to succeed. That problem is fixed in Gnulib. Right. > The only disagreement between Gnulib and old (2.28) glibc in this > area, is in relatively obscure cases where we have not seen any bug > reports, and in these cases old glibc mostly gets it wrong (for > example, see my previous email), whereas Gnulib mostly gets it right. > Let's stick with the Gnulib behavior here. What I'd like to see here as an outcome is a broader battery of tests in glibc that cover the mktime() behaviour we want to support. We'll work on that and review the recommended gnulib changes. We have also seen a somewhat odd use of mktime() to detect DST transitions that DJ and I need to audit and verify against the changes you have implemented in gnulib. Thanks for the quick comments. I think the next step is with us to do more testing. -- Cheers, Carlos.