From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.8 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, SPF_HELO_NONE,SPF_NONE shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id BF04F1F4B7 for ; Fri, 23 Aug 2019 18:29:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405162AbfHWS31 (ORCPT ); Fri, 23 Aug 2019 14:29:27 -0400 Received: from mail-vs1-f41.google.com ([209.85.217.41]:36968 "EHLO mail-vs1-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404001AbfHWS31 (ORCPT ); Fri, 23 Aug 2019 14:29:27 -0400 Received: by mail-vs1-f41.google.com with SMTP id q188so6871617vsa.4 for ; Fri, 23 Aug 2019 11:29:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=wPDeHScAeTGqVRqEH0EuVqi/senwT6mJaCV9dS5ItR8=; b=O1EUuYH5obA1e1CTUfgXr5uPyNMIwD0fbyDdOf0E7sSFfPVwHUIZXAB2dCwmny/xaK oT/h5KRxRWNWu9vfKiSDar7Q/3ABDpQFKODMfJsQc9kJRzTdu/XHfn/svcMRkNV38XCa +e3dHMYzAq0yX1z6M/K8altIvODxm/fENnesgmhoGX+XHf1X761FYc5zXRew4J7aNgkz eXj6tTDdXVxl7Ju7QfHviiymZPeX4eboaU8TFgQ7nsgQqENNPrmpR6V8QujXUCrJxyDT MD0oqzTGGhH2ogschZViP+PkYBEDqVmBuPKZ2nHDixS4nPv2+FKZIanqE3uqCLXrb1+Y NAHg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=wPDeHScAeTGqVRqEH0EuVqi/senwT6mJaCV9dS5ItR8=; b=kf4qvl6byKp0BwlIhUakKnx4P5yRwJfiemDXsnrgEVBv3LhCq7iV9LQy5ByUbYbqWH exrfEP4L2uFy56MV1hYBs0M6vrge6ydDjiSCQauRxtM/96gVYcnnYO6okHKRUGYtvxrN cVRk93l0CFu/Gy3ePkOQtruhDLI5UBuYOM1oFZon1ctrQrLfbAG5UAU4AIA0Pg/sIAiC FLmlZePN6KhnABf05Z4Npkf/D5x1dvIuKwuGSgyg92zo06M8qD6qw8Nm2ImyAmHODJqm 4qCgtCuHB4RisN20prlIpPYZQvdzvoOREA3/DXXO1LJkJQW19b758bGwomegZT0moCVp NnZQ== X-Gm-Message-State: APjAAAXZ1RQ1IRxOH4mR7mga/xDgywt63fD+ikb7SPHQnFCIExAlXoMg QgDg51Dq9s22Kb4BMDy+Qylh9UeTfPtKUmfug14= X-Google-Smtp-Source: APXvYqza9GcGKQjr86fACRbkNP+mhRqiwc2AIw6dlXWG6njsaR0gjUOKwYJZJ3BTbhN2Z43FmJ3qCfH3DWZzP4q5Wo8= X-Received: by 2002:a67:6244:: with SMTP id w65mr3610162vsb.117.1566584965988; Fri, 23 Aug 2019 11:29:25 -0700 (PDT) MIME-Version: 1.0 References: <20190823030059.47ftwfne6y436e5j@dcvr> In-Reply-To: From: Elijah Newren Date: Fri, 23 Aug 2019 11:29:14 -0700 Message-ID: Subject: Re: RFC: Proposing git-filter-repo for inclusion in git.git To: Eric Wong Cc: Junio C Hamano , Git Mailing List , =?UTF-8?B?w4Z2YXIgQXJuZmrDtnLDsCBCamFybWFzb24=?= , Johannes Schindelin , Lars Schneider , Jonathan Nieder Content-Type: text/plain; charset="UTF-8" Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Fri, Aug 23, 2019 at 11:06 AM Elijah Newren wrote: > Safety: Ooh, and another one I remembered just after hitting 'send': * If the user provides a --tag-name-filter that maps multiple tags to the same name, no warning or error is provided; filter-branch simply overwrites each tag in some undocumented pre-defined order (lexicographic) resulting in only one tag at the end. A regression test will fail if you attempt to error out and warn the user, so if you are trying to make a backward compatible reimplementation you have to add extra code to detect collisions and make sure that only the lexicographically last one is rewritten. (fast-import will naturally error out if told to write the same tag more than once, so you have to avoid triggering it.) > Summary of above: Anything compatible with git-filter-branch will be > slower than molasses and extraordinarily unsafe.