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,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 8B99E1F6C1 for ; Wed, 24 Aug 2016 17:32:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754291AbcHXRcw (ORCPT ); Wed, 24 Aug 2016 13:32:52 -0400 Received: from cloud.peff.net ([104.130.231.41]:60568 "HELO cloud.peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754248AbcHXRcw (ORCPT ); Wed, 24 Aug 2016 13:32:52 -0400 Received: (qmail 12604 invoked by uid 109); 24 Aug 2016 17:32:51 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.84) with SMTP; Wed, 24 Aug 2016 17:32:51 +0000 Received: (qmail 4787 invoked by uid 111); 24 Aug 2016 17:32:55 -0000 Received: from sigill.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.7) by peff.net (qpsmtpd/0.84) with SMTP; Wed, 24 Aug 2016 13:32:55 -0400 Received: by sigill.intra.peff.net (sSMTP sendmail emulation); Wed, 24 Aug 2016 13:32:48 -0400 Date: Wed, 24 Aug 2016 13:32:48 -0400 From: Jeff King To: Junio C Hamano Cc: Johannes Schindelin , git@vger.kernel.org, Torsten =?utf-8?Q?B=C3=B6gershausen?= Subject: Re: [PATCH v2 0/4] cat-file: optionally convert to worktree version Message-ID: <20160824173248.ami3hgadea5zjvf3@sigill.intra.peff.net> References: <20160824161939.d2h4qlaxhhi6limm@sigill.intra.peff.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Wed, Aug 24, 2016 at 10:02:39AM -0700, Junio C Hamano wrote: > Jeff King writes: > > > On Wed, Aug 24, 2016 at 09:09:06AM -0700, Junio C Hamano wrote: > > > >> > + if (!path) > >> > + path = obj_context.path; > >> > + else if (obj_context.mode == S_IFINVALID) > >> > + obj_context.mode = 0100644; > >> > + > >> > buf = NULL; > >> > switch (opt) { > >> > case 't': > >> > >> The above two hunks make all the difference in the ease of reading > >> the remainder of the function. Very good. > > > > Yeah, I agree. Though it took me a moment to figure out why we were > > setting obj_context.mode but not obj_context.path; the reason is that > > "mode" is convenient to use as local storage, but "path" is not, because > > it is not a pointer but an array. > > Wait a minute. Why is it a cascaded if/elseif, not two independent > if statements that gives a default value? In other words, wouldn't > these two independent and orthogonal decisions? > > * When forced to use some path, we ignore obj_context.path > > * Whether we are forced to use a path or not, if we do not know the > mode from the lookup context, we want to use the regular blob > mode. > > So that part of the patch is wrong after all, I would have to say. > > if (!path) > path = obj_context.path; > if (obj_context.mode == S_IFINVALID) > obj_context.mode = 0100644; > > or something like that, perhaps. Oh, hrm, you are right. I assumed we wanted to force the mode when --path was in effect, but that is not what the original does. If you say: --path=foo HEAD:bar then we will take the mode for "bar", whatever it is (maybe a tree or symlink). But if you say: --path=foo $(git rev-parse HEAD:bar) then we will use 100644, regardless of what "bar" is in HEAD. I have not thought about it enough to know if that is a good thing or a bad thing. But I'll bet Dscho has, so I will wait for him to comment. :) > > if (!force_path) { > > /* use file info from sha1 lookup */ > > path = obj_context.path; > > mode = obj_context.mode; > > } else { > > /* use path requested by user, and assume it is a regular file */ > > path = force_path; > > mode = 0100644; > > } > > Hmph, if you read it that way, then if/elseif makes some sense, but > we need to assume that the obj_context.mode can be garbage and have > a fallback for it. > > Just like > > git cat-file --filters --path=git.c HEAD:t > > would error out because HEAD:t is not even a blob, I would expect > > git cat-file --filters --path=git.c :RelNotes > > to error out, because the object itself _is_ known to be a > blob that is not a regular file. > > And that kind of type checking will not be possible with "if the > user gave us a path, assume it is a regular file". Right, I agree that is the outcome, but I just wasn't sure that the second case _should_ error out. IOW, does "--filters --path" mean "treat this as a regular file at path X", or is the "regular file" part not implied? I don't suppose anybody cares that much either way, but it feels weird to behave differently depending on how we looked up the blob (whereas for the HEAD:t case, a tree is always a tree). -Peff