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=-3.9 required=3.0 tests=AWL,BAYES_00, 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 A3A7A1F462 for ; Thu, 20 Jun 2019 05:25:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726084AbfFTFVa (ORCPT ); Thu, 20 Jun 2019 01:21:30 -0400 Received: from cloud.peff.net ([104.130.231.41]:45156 "HELO cloud.peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1725857AbfFTFV3 (ORCPT ); Thu, 20 Jun 2019 01:21:29 -0400 Received: (qmail 16065 invoked by uid 109); 20 Jun 2019 05:18:15 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with SMTP; Thu, 20 Jun 2019 05:18:15 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 12339 invoked by uid 111); 20 Jun 2019 05:22:16 -0000 Received: from sigill.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.7) by peff.net (qpsmtpd/0.94) with (ECDHE-RSA-AES256-GCM-SHA384 encrypted) SMTP; Thu, 20 Jun 2019 01:22:16 -0400 Authentication-Results: peff.net; auth=none Received: by sigill.intra.peff.net (sSMTP sendmail emulation); Thu, 20 Jun 2019 01:21:25 -0400 Date: Thu, 20 Jun 2019 01:21:25 -0400 From: Jeff King To: Denton Liu Cc: "Pugh, Logan" , "git@vger.kernel.org" Subject: Re: [2.22.0] difftool no longer passes through to git diff if diff.tool is unset Message-ID: <20190620052125.GA12434@sigill.intra.peff.net> References: <20190620011744.GA3696@archbookpro.localdomain> <20190620024517.GA24321@archbookpro.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190620024517.GA24321@archbookpro.localdomain> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Wed, Jun 19, 2019 at 10:45:17PM -0400, Denton Liu wrote: > Using the following command on git.git, > > $ HOME=/dev/null ./git --exec-path=. difftool --no-index color.c color.h > > I did a quick bisect on the issue and it seems like the cause of this > bug is actually 287ab28bfa (diff: reuse diff setup for --no-index case, > 2019-02-16). I'll do a bit more digging tomorrow. I don't know much about how git-difftool works, but it looks like it sets GIT_EXTERNAL_DIFF=git-difftool--helper. Prior to 287ab28bfa, we would not have respected any external diff command when running git-diff. But after it, we do. In the case that he user has not provided --no-index, then this all works as I guess difftool is meant to: it runs the helper and says "hey, you have not configured this". It seems like the behavior of the above command prior to 287ab28bfa was not intentional. It would run git-diff, expecting it to trigger the helper, but it never did (and instead just did a normal no-index diff). So it seems like the new behavior is actually the right thing, as it makes the --no-index case consistent with the regular one? I'm not at all clear why you would run "difftool" here if you it is not configured and you just want the straight diff output. -Peff