From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: [PATCH v3 2/3] patch-id: document new behaviour Date: Sun, 30 Mar 2014 21:09:26 +0300 Message-ID: <1396202583-2572-2-git-send-email-mst@redhat.com> References: <1396202583-2572-1-git-send-email-mst@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: sunshine@sunshineco.com, jrnieder@gmail.com, peff@peff.net, gitster@pobox.com To: git@vger.kernel.org X-From: git-owner@vger.kernel.org Sun Mar 30 20:09:28 2014 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1WUKAf-0006eV-Oy for gcvg-git-2@plane.gmane.org; Sun, 30 Mar 2014 20:09:26 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751736AbaC3SJK (ORCPT ); Sun, 30 Mar 2014 14:09:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:4204 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750882AbaC3SJJ (ORCPT ); Sun, 30 Mar 2014 14:09:09 -0400 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s2UI8xxn004431 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Sun, 30 Mar 2014 14:08:59 -0400 Received: from redhat.com (vpn1-7-185.ams2.redhat.com [10.36.7.185]) by int-mx12.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with SMTP id s2UI8vOM014487; Sun, 30 Mar 2014 14:08:58 -0400 Content-Disposition: inline In-Reply-To: <1396202583-2572-1-git-send-email-mst@redhat.com> X-Mutt-Fcc: =sent X-Scanned-By: MIMEDefang 2.68 on 10.5.11.25 Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Clarify that patch ID is now a sum of hashes, not a hash. Document --stable and --unstable flags. Signed-off-by: Michael S. Tsirkin --- changes from v2: explicitly list the kinds of changes against which patch ID is stable Documentation/git-patch-id.txt | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) diff --git a/Documentation/git-patch-id.txt b/Documentation/git-patch-id.txt index 312c3b1..30923e0 100644 --- a/Documentation/git-patch-id.txt +++ b/Documentation/git-patch-id.txt @@ -8,14 +8,14 @@ git-patch-id - Compute unique ID for a patch SYNOPSIS -------- [verse] -'git patch-id' < +'git patch-id' [--stable | --unstable] < DESCRIPTION ----------- -A "patch ID" is nothing but a SHA-1 of the diff associated with a patch, with -whitespace and line numbers ignored. As such, it's "reasonably stable", but at -the same time also reasonably unique, i.e., two patches that have the same "patch -ID" are almost guaranteed to be the same thing. +A "patch ID" is nothing but a sum of SHA-1 of the diff hunks associated with a +patch, with whitespace and line numbers ignored. As such, it's "reasonably +stable", but at the same time also reasonably unique, i.e., two patches that +have the same "patch ID" are almost guaranteed to be the same thing. IOW, you can use this thing to look for likely duplicate commits. @@ -27,6 +27,19 @@ This can be used to make a mapping from patch ID to commit ID. OPTIONS ------- + +--stable:: + Use a symmetrical sum of hashes as the patch ID. + With this option, reordering file diffs that make up a patch or + splitting a diff up to multiple diffs that touch the same path + does not affect the ID. + This is the default. + +--unstable:: + Use a non-symmetrical sum of hashes, such that reordering + or splitting the patch does affect the ID. + This was the default value for git 1.9 and older. + :: The diff to create the ID of. -- MST