From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.5 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,T_RP_MATCHES_RCVD shortcircuit=no autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 1B1EE1FC34 for ; Fri, 8 Dec 2017 20:20:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751190AbdLHUT7 (ORCPT ); Fri, 8 Dec 2017 15:19:59 -0500 Received: from cloud.peff.net ([104.130.231.41]:52780 "HELO cloud.peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750908AbdLHUT7 (ORCPT ); Fri, 8 Dec 2017 15:19:59 -0500 Received: (qmail 27293 invoked by uid 109); 8 Dec 2017 20:19:59 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with SMTP; Fri, 08 Dec 2017 20:19:59 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 5493 invoked by uid 111); 8 Dec 2017 20:20:20 -0000 Received: from sigill.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.7) by peff.net (qpsmtpd/0.94) with ESMTPA; Fri, 08 Dec 2017 15:20:20 -0500 Authentication-Results: peff.net; auth=pass (cram-md5) smtp.auth=relayok Received: by sigill.intra.peff.net (sSMTP sendmail emulation); Fri, 08 Dec 2017 15:19:57 -0500 Date: Fri, 8 Dec 2017 15:19:57 -0500 From: Jeff King To: Ramsay Jones Cc: Stefan Beller , git@vger.kernel.org Subject: Re: [PATCH 1/1] diffcore: add a filter to find a specific blob Message-ID: <20171208201957.GA456@sigill.intra.peff.net> References: <20171208002447.20261-1-sbeller@google.com> <20171208002447.20261-2-sbeller@google.com> <20171208093434.GD26199@sigill.intra.peff.net> <643e1afd-43e2-7fcc-452b-8b9ceac6868c@ramsayjones.plus.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <643e1afd-43e2-7fcc-452b-8b9ceac6868c@ramsayjones.plus.com> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Fri, Dec 08, 2017 at 04:28:23PM +0000, Ramsay Jones wrote: > On 08/12/17 09:34, Jeff King wrote: > > On Thu, Dec 07, 2017 at 04:24:47PM -0800, Stefan Beller wrote: > [snip] > >> Junio hinted at a different approach of solving this problem, which this > >> patch implements. Teach the diff machinery another flag for restricting > >> the information to what is shown. For example: > >> > >> $ ./git log --oneline --blobfind=v2.0.0:Makefile > >> b2feb64309 Revert the whole "ask curl-config" topic for now > >> 47fbfded53 i18n: only extract comments marked with "TRANSLATORS:" > >> > >> we observe that the Makefile as shipped with 2.0 was introduced in > >> v1.9.2-471-g47fbfded53 and replaced in v2.0.0-rc1-5-gb2feb64309 by > >> a different blob. > > Sorry, this has nothing to do with this specific thread. :( > > However, the above caught my eye. Commit b2feb64309 does not 'replace > the Makefile with a different blob'. That commit was a 'last minute' > revert of a topic _prior_ to v2.0.0, which resulted in the _same_ > blob as commit 47fbfded53. (i.e. a53f3a8326c2e62dc79bae7169d64137ac3dab20). Right, I think the patch is working as advertised but the commit message misinterprets the results. :) If you add --raw, you can see that both commits introduce that blob, and it never "goes away". That's because that happened in a merge, which we don't diff in a default log invocation. And in fact finding where this "goes away" is hard, because the merge doesn't trigger "-c" or "--cc". It's 8eaf517835, which presumably was forked before the revert in b2feb64309, and then the merge was able to replace that blob completely with the other side of the merge. Viewing with "-m" turns up a bunch of uninteresting merges. Looking at "--first-parent" is how I got 8eaf517835. So I think this one is tricky because of the revert. In the same way that pathspec-limiting is often tricky in the face of a revert, because the merges "hide" interesting things happening. -Peff