From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Zefram Newsgroups: gmane.lisp.guile.bugs Subject: bug#26632: TAI<->UTC conversion botches 1961 to 1971 Date: Mon, 24 Apr 2017 02:02:18 +0100 Message-ID: <20170424010218.GL6765@fysh.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: blaine.gmane.org 1492995813 8404 195.159.176.226 (24 Apr 2017 01:03:33 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 24 Apr 2017 01:03:33 +0000 (UTC) To: 26632@debbugs.gnu.org Original-X-From: bug-guile-bounces+guile-bugs=m.gmane.org@gnu.org Mon Apr 24 03:03:23 2017 Return-path: Envelope-to: guile-bugs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1d2SPR-0001wB-GP for guile-bugs@m.gmane.org; Mon, 24 Apr 2017 03:03:21 +0200 Original-Received: from localhost ([::1]:41158 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d2SPX-0005Fg-4p for guile-bugs@m.gmane.org; Sun, 23 Apr 2017 21:03:27 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:49183) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d2SPH-0005Ak-B0 for bug-guile@gnu.org; Sun, 23 Apr 2017 21:03:16 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d2SP8-0008Mu-Pv for bug-guile@gnu.org; Sun, 23 Apr 2017 21:03:11 -0400 Original-Received: from debbugs.gnu.org ([208.118.235.43]:38759) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1d2SP8-0008Mk-MQ for bug-guile@gnu.org; Sun, 23 Apr 2017 21:03:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1d2SP8-0006NW-BV for bug-guile@gnu.org; Sun, 23 Apr 2017 21:03:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Zefram Original-Sender: "Debbugs-submit" Resent-CC: bug-guile@gnu.org Resent-Date: Mon, 24 Apr 2017 01:03:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: report 26632 X-GNU-PR-Package: guile X-GNU-PR-Keywords: X-Debbugs-Original-To: bug-guile@gnu.org Original-Received: via spool by submit@debbugs.gnu.org id=B.149299577724497 (code B ref -1); Mon, 24 Apr 2017 01:03:02 +0000 Original-Received: (at submit) by debbugs.gnu.org; 24 Apr 2017 01:02:57 +0000 Original-Received: from localhost ([127.0.0.1]:36958 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1d2SOy-0006Ms-UD for submit@debbugs.gnu.org; Sun, 23 Apr 2017 21:02:57 -0400 Original-Received: from eggs.gnu.org ([208.118.235.92]:58148) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1d2SOt-0006ML-7p for submit@debbugs.gnu.org; Sun, 23 Apr 2017 21:02:52 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d2SOj-0008G2-MV for submit@debbugs.gnu.org; Sun, 23 Apr 2017 21:02:42 -0400 Original-Received: from lists.gnu.org ([2001:4830:134:3::11]:44954) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1d2SOj-0008Fy-Jq for submit@debbugs.gnu.org; Sun, 23 Apr 2017 21:02:37 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:49108) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d2SOe-00055H-RC for bug-guile@gnu.org; Sun, 23 Apr 2017 21:02:37 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d2SOa-0008EF-DA for bug-guile@gnu.org; Sun, 23 Apr 2017 21:02:32 -0400 Original-Received: from river6.fysh.org ([2001:41d0:d:20da::2]:34710 helo=river.fysh.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1d2SOa-0008D7-39 for bug-guile@gnu.org; Sun, 23 Apr 2017 21:02:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=fysh.org; s=20170316; h=Content-Type:MIME-Version:Message-ID:Subject:To:From:Date; bh=4CURIA3HFcx9WEuF2Q1PJofcTClP5tZfecA7g2TwMnI=; b=XeW7voiWcVv7giQtDxh38gnYK1Ay9yqTKENDv+0zO/IX1bY2f5h10DOFP2CKSKJiXDJwl51BflIW8iiY9EwqpYhq0gYat3KbGm0AH0iDbvuMFC1OyXlig848vK6zIZBw2VG6RimMMAWakLfoxgcsHJDL7WaDroNVx3YIaOVVVMs=; Original-Received: from zefram by river.fysh.org with local (Exim 4.84_2 #1 (Debian)) id 1d2SOQ-0006e3-K2; Mon, 24 Apr 2017 02:02:18 +0100 Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 208.118.235.43 X-BeenThere: bug-guile@gnu.org List-Id: "Bug reports for GUILE, GNU's Ubiquitous Extension Language" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-guile-bounces+guile-bugs=m.gmane.org@gnu.org Original-Sender: "bug-guile" Xref: news.gmane.org gmane.lisp.guile.bugs:8783 Archived-At: The SRFI-19 library gets TAI<->UTC conversions badly wrong in the years 1961 to 1971 (inclusive). This has to be examined somewhat indirectly, because SRFI-19 doesn't offer any way to display a TAI time in its conventional form as a date-like structure, nor to input a TAI time from such a structure. SRFI-19's date structure, as implemented, is always interpreted according to UTC. The only operations supported on TAI time structures are conversions to and from the various forms of UTC, conversions to and from the less-useful `monotonic' time, and arithmetic operations. Thus the erroneous TAI<->UTC conversions only come out through arithmetic operations in TAI space. One must also be careful to avoid unrelated bugs such as bug#21911. First I'll consider an ordinary day in 1967: scheme@(guile-user)> (use-modules (srfi srfi-19)) scheme@(guile-user)> (time-difference ... (time-utc->time-tai (date->time-utc (make-date 0 0 0 0 15 3 1967 0))) ... (time-utc->time-tai (date->time-utc (make-date 0 0 0 0 14 3 1967 0)))) $1 = #