From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 580D01FF40 for ; Tue, 21 Jun 2016 19:32:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751782AbcFUTcj (ORCPT ); Tue, 21 Jun 2016 15:32:39 -0400 Received: from pb-smtp2.pobox.com ([64.147.108.71]:53331 "EHLO sasl.smtp.pobox.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751002AbcFUTci (ORCPT ); Tue, 21 Jun 2016 15:32:38 -0400 Received: from sasl.smtp.pobox.com (unknown [127.0.0.1]) by pb-smtp2.pobox.com (Postfix) with ESMTP id BD802245C5; Tue, 21 Jun 2016 15:32:36 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; s=sasl; bh=ATgg96GKzOSb2eDObQJPtAxTBKw=; b=oTeLxh 0Mu+Qz4T4s8DHqVdxy6IQPXweYtPbA6z1Fy5R3rdj0rKS7k9D3yj9BQQVjUJkhlk YrzXujd22niB0wUQ3+2uNlQivkFks+FGQAFmRWSyn1kkRuB2LKZDXwBXcBlrkAYt bDu0rDfR9irb3lJBNAv4e7C6O7kYdEfH4QwSI= DomainKey-Signature: a=rsa-sha1; c=nofws; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; q=dns; s=sasl; b=NFlOVyK6nLN6J1FCJaUbp8Gt7xws099q 2y+FeiKS0zS8LgH87Fkma6L+bO8tD4bZP0soU0cL8BtC/8vv7h2uIXHhn040uFkX 5F+Ey/+lyfjjbvuzGOtQnfXhFDP86KDenL4PmRjfvvNcxPVkaAyihFcRtbYwvJt4 jYXl8wHm1UA= Received: from pb-smtp2.nyi.icgroup.com (unknown [127.0.0.1]) by pb-smtp2.pobox.com (Postfix) with ESMTP id B5DC1245C4; Tue, 21 Jun 2016 15:32:36 -0400 (EDT) Received: from pobox.com (unknown [104.132.0.95]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by pb-smtp2.pobox.com (Postfix) with ESMTPSA id 3D28C245C2; Tue, 21 Jun 2016 15:32:36 -0400 (EDT) From: Junio C Hamano To: Johannes Schindelin Cc: git@vger.kernel.org, Eric Sunshine , Paul Tan Subject: Re: [PATCH v3 2/9] Disallow diffopt.close_file when using the log_tree machinery References: <973f9f676225aa98377f607ced1ff474f39b863f.1466505222.git.johannes.schindelin@gmx.de> Date: Tue, 21 Jun 2016 12:32:34 -0700 In-Reply-To: (Junio C. Hamano's message of "Tue, 21 Jun 2016 12:05:59 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Pobox-Relay-ID: E8696EDE-37E6-11E6-AC4B-EE617A1B28F4-77302942!pb-smtp2.pobox.com Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Junio C Hamano writes: > Junio C Hamano writes: > >> Johannes Schindelin writes: >> >>> We are about to teach the log_tree machinery to reuse the diffopt.file >>> setting to output to a file stream different from stdout. >>> >>> This means that builtin am can no longer ask the diff machinery to >>> close the file when actually calling the log_tree machinery (which >>> wants to flush the very same file stream that would then already be >>> closed). >> >> Sorry for being slow, but I am not sure why the first paragraph has >> to mean the second paragraph. This existing caller opens a new >> stream, sets .fp to it, and expects that the log_tree_commit() to >> close it if told by setting .close_file to true, all of which sounds >> sensible. >> >> If a codepath wants to use the same stream for two or more calls to >> log_tree by pointing the stream with .fp, it would be of course a >> problem for the caller to set .close_file to true in its first call, >> as .fp will be closed and no longer usable for second and subsequent >> call, and that would be a bug, but for a single-shot call it feels >> entirely a sensible request to make, no? >> >> Obviously you have looked at the codepaths involved a lot longer >> than I did, and I do not doubt your conclusion, but I cannot quite >> convince myself with the above explanation. >> >> The option parser of "git diff" family sets ->close_file to true >> when the --output option is given. >> >> Wouldn't this patch break "git log --output=foo -3"? > > I wonder if the right approach is to stop using .close_file > everywhere. > > With this "do not set .close_file if you use log_tree_commit()", > "git log --output=/dev/stdout -3" gets broken, but removing that > check is not sufficient to correct the same command with "-p", as > letting .close_file to close the output file after finishing a > single diff would mean that subsequent write to the same file > descriptor will trigger a failure. We could say "git log --output=foo -3 [-p]" without any of your patches is already broken, and it is a valid excuse to take this change that we are not making things worse with it. It is just 3/9 is a logical first step to correct that exact problem, i.e. some codepaths, even though there is a place that holds the output stream and command line parser does prepare one for "foo" when --output=foo is given, ignore it and send thigns to the standard output stream. You might not have written 3/9 in order to fix that "git log --output=foo" problem, but a fix for it should look exactly like your 3/9, I would think. And it is sad that this step makes that fix impossible.