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From: Elijah Newren <newren@gmail.com>
To: Phillip Wood <phillip.wood@dunelm.org.uk>
Cc: Git Mailing List <git@vger.kernel.org>,
	Johannes Schindelin <johannes.schindelin@gmx.de>,
	Junio C Hamano <gitster@pobox.com>
Subject: Re: [RFC PATCH v2 7/7] git-rebase: make --allow-empty-message the default
Date: Wed, 20 Jun 2018 09:47:12 -0700	[thread overview]
Message-ID: <CABPp-BHrcUHX_zHxpojV5=sxJ1=NoDg9uhxv+NH5BsHsQYavPQ@mail.gmail.com> (raw)
In-Reply-To: <e8a6f54e-4361-dc66-c833-6047f8ea2058@talktalk.net>

Hi Phillip,

On Sun, Jun 17, 2018 at 8:30 AM, Phillip Wood <phillip.wood@talktalk.net> wrote:

> Looking at the option parsing in git-rebase.sh it appears that it does not
> check for --no-allow-empty-message so there's no way to turn off the default
> for those modes that support it. I'm not sure what to think of this change,
> I'm slightly uneasy with changing to default to be different from
> cherry-pick, though one could argue rebasing is a different operation and
> just keeping the existing messages even if they are empty is more
> appropriate and having all the rebase modes do the default to the same
> behaviour is definitely an improvement.
>

Here's my extended rationale for why to change the default for rebase
-i/-m (and _maybe_ also for cherry-pick):

First, commits with an empty commit message are fairly rare, so it's
hard to gather that much data on; we're dealing with out-liers.  That
also means that folks who have touched the area in the past probably
weren't dealing with full information either; they just tweaked what
was already there.

It makes sense that git-commit would default to not allowing empty
commit messages without a flag.  We'd like to warn against that kind
of poor practice.  However, that implicitly means that commands which
build on top of git-commit might copy that default even when it
doesn't make sense.  So it's not at all clear to me that cherry-pick
or rebase -i/-m should have the same default.  They do, but that may
have been entirely accidental.  And when someone comes along and
notices the problematic default of stopping with empty commit
messages, they assume it was intended and add a flag to change it, as
happened for both commands.

On the other hand git-am was designed from the workflow of applying
many patches from the beginning, and has a different default.
am-based rebases copy that default of silently applying commits with
empty commit messages; it may not be clear that rebase should copy the
default from am, but it does.  Yet, despite the fact that ignoring
empty commit messages is the default backend for rebases, and thus is
likely used more than the other rebase backends, no one has ever
submitted a patch to add a flag to rebase to get the opposite
behavior.  To me, this argues pretty strongly that not only is
ignoring empty messages the right default, that it's a waste of time
to implement a flag (e.g. --no-allow-empty-message) providing the
opposite behavior for rebases.

It is obvious that one of the two rebase backends have the wrong
default, because they should have the same default as each other.  I
am inclined to believe, based on the above logic, that am-based rebase
has the correct default.  I also suspect that cherry-pick has the
wrong default, though it's not as cut-and-dry since it doesn't have
multiple backends with conflicting defaults.


Does that make sense?  Am I overlooking anything important?

  reply	other threads:[~2018-06-20 16:47 UTC|newest]

Thread overview: 130+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-07  4:58 RFC: rebase inconsistency in 2.18 -- course of action? Elijah Newren
2018-06-07  5:04 ` [PATCH] t3401: add directory rename testcases for rebase and am Elijah Newren
2018-06-25 16:17   ` Elijah Newren
2018-06-07  5:05 ` [PATCH] apply: fix grammar error in comment Elijah Newren
2018-06-07  5:05 ` [PATCH] t5407: fix test to cover intended arguments Elijah Newren
2018-06-07  5:06 ` [PATCH] git-rebase--merge: modernize "git-$cmd" to "git $cmd" Elijah Newren
2018-06-07  5:24   ` Elijah Newren
2018-06-27  7:46   ` [PATCH v2] " Elijah Newren
2018-07-12 15:49     ` Johannes Schindelin
2018-07-13 16:13       ` Elijah Newren
2018-07-14 22:20         ` Johannes Schindelin
2018-06-07  5:06 ` [PATCH 1/2] t3422: new testcases for checking when incompatible options passed Elijah Newren
2018-06-07  5:06   ` [PATCH 2/2] git-rebase: error out " Elijah Newren
2018-06-10 19:40     ` Phillip Wood
2018-06-11 15:19       ` Elijah Newren
2018-06-11 15:59         ` Phillip Wood
2018-06-11 15:49       ` Elijah Newren
2018-06-12  9:45         ` Phillip Wood
2018-06-17  5:58   ` [RFC PATCH v2 0/7] Document/fix/warn about rebase incompatibilities and inconsistences Elijah Newren
2018-06-17  5:58     ` [RFC PATCH v2 1/7] git-rebase.txt: document incompatible options Elijah Newren
2018-06-17 15:38       ` Phillip Wood
2018-06-20 17:09         ` Elijah Newren
2018-06-17 17:15       ` Eric Sunshine
2018-06-20 17:10         ` Elijah Newren
2018-06-17  5:58     ` [RFC PATCH v2 2/7] git-rebase.sh: update help messages a bit Elijah Newren
2018-06-17  5:58     ` [RFC PATCH v2 3/7] t3422: new testcases for checking when incompatible options passed Elijah Newren
2018-06-17  5:58     ` [RFC PATCH v2 4/7] git-rebase: error out " Elijah Newren
2018-06-17  5:58     ` [RFC PATCH v2 5/7] git-rebase.txt: document behavioral inconsistencies between modes Elijah Newren
2018-06-17  5:58     ` [RFC PATCH v2 6/7] git-rebase.txt: address confusion between --no-ff vs --force-rebase Elijah Newren
2018-06-17  5:58     ` [RFC PATCH v2 7/7] git-rebase: make --allow-empty-message the default Elijah Newren
2018-06-17 15:30       ` Phillip Wood
2018-06-20 16:47         ` Elijah Newren [this message]
2018-06-17 15:41     ` [RFC PATCH v2 0/7] Document/fix/warn about rebase incompatibilities and inconsistences Phillip Wood
2018-06-21 15:00     ` [PATCH v3 0/7] Document/fix/warn about rebase incompatibilities and inconsistencies Elijah Newren
2018-06-21 15:00       ` [PATCH v3 1/7] git-rebase.txt: document incompatible options Elijah Newren
2018-06-21 19:47         ` Junio C Hamano
2018-06-21 20:33           ` Elijah Newren
2018-06-22  8:32         ` SZEDER Gábor
2018-06-21 15:00       ` [PATCH v3 2/7] git-rebase.sh: update help messages a bit Elijah Newren
2018-06-21 19:58         ` Junio C Hamano
2018-06-21 20:34           ` Elijah Newren
2018-06-21 15:00       ` [PATCH v3 3/7] t3422: new testcases for checking when incompatible options passed Elijah Newren
2018-06-21 20:04         ` Junio C Hamano
2018-06-21 20:37           ` Elijah Newren
2018-06-21 21:18           ` Eric Sunshine
2018-06-21 15:00       ` [PATCH v3 4/7] git-rebase: error out " Elijah Newren
2018-06-21 20:29         ` Junio C Hamano
2018-06-21 20:41           ` Elijah Newren
2018-06-21 15:00       ` [PATCH v3 5/7] git-rebase.txt: document behavioral inconsistencies between modes Elijah Newren
2018-06-21 20:44         ` Junio C Hamano
2018-06-21 21:25           ` Elijah Newren
2018-06-21 15:00       ` [PATCH v3 6/7] git-rebase.txt: address confusion between --no-ff vs --force-rebase Elijah Newren
2018-06-21 20:46         ` Junio C Hamano
2018-06-21 21:22           ` Elijah Newren
2018-06-21 15:00       ` [RFC PATCH v3 7/7] git-rebase: make --allow-empty-message the default Elijah Newren
2018-06-25 16:12       ` [PATCH v4 0/9] Document/fix/warn about rebase incompatibilities and inconsistencies Elijah Newren
2018-06-25 16:12         ` [PATCH v4 1/9] git-rebase.txt: document incompatible options Elijah Newren
2018-06-25 16:12         ` [PATCH v4 2/9] git-rebase.sh: update help messages a bit Elijah Newren
2018-06-25 16:12         ` [PATCH v4 3/9] t3422: new testcases for checking when incompatible options passed Elijah Newren
2018-06-26 18:17           ` Junio C Hamano
2018-06-27  6:50             ` Elijah Newren
2018-06-25 16:12         ` [PATCH v4 4/9] git-rebase: error out " Elijah Newren
2018-06-25 16:12         ` [PATCH v4 5/9] git-rebase.txt: address confusion between --no-ff vs --force-rebase Elijah Newren
2018-06-25 16:12         ` [PATCH v4 6/9] directory-rename-detection.txt: technical docs on abilities and limitations Elijah Newren
2018-06-25 16:12         ` [PATCH v4 7/9] git-rebase.txt: document behavioral differences between modes Elijah Newren
2018-06-25 16:12         ` [PATCH v4 8/9] t3401: add directory rename testcases for rebase and am Elijah Newren
2018-06-25 16:13         ` [RFC PATCH v4 9/9] git-rebase: make --allow-empty-message the default Elijah Newren
2018-06-27  7:23         ` [PATCH v5 0/9] Document/fix/warn about rebase incompatibilities and inconsistencies Elijah Newren
2018-06-27  7:23           ` [PATCH v5 1/9] git-rebase.txt: document incompatible options Elijah Newren
2018-06-27  7:23           ` [PATCH v5 2/9] git-rebase.sh: update help messages a bit Elijah Newren
2018-06-27  7:23           ` [PATCH v5 3/9] t3422: new testcases for checking when incompatible options passed Elijah Newren
2018-06-27  7:23           ` [PATCH v5 4/9] git-rebase: error out " Elijah Newren
2018-06-27  7:23           ` [PATCH v5 5/9] git-rebase.txt: address confusion between --no-ff vs --force-rebase Elijah Newren
2018-06-27  7:23           ` [PATCH v5 6/9] directory-rename-detection.txt: technical docs on abilities and limitations Elijah Newren
2018-06-27  7:23           ` [PATCH v5 7/9] git-rebase.txt: document behavioral differences between modes Elijah Newren
2018-06-27  7:23           ` [PATCH v5 8/9] t3401: add directory rename testcases for rebase and am Elijah Newren
2018-06-27  7:23           ` [RFC PATCH v5 9/9] git-rebase: make --allow-empty-message the default Elijah Newren
2018-09-12  2:42             ` 2.19.0 regression: leaving editor with empty commit message doesn't stop rebase [was: Re: [RFC PATCH v5 9/9] git-rebase: make --allow-empty-message the default] SZEDER Gábor
2018-09-12  6:21               ` Elijah Newren
2018-09-12 21:18               ` [PATCH] sequencer: fix --allow-empty-message behavior, make it smarter Elijah Newren
2018-09-13 20:24                 ` Junio C Hamano
2018-06-29 13:20           ` [PATCH v5 0/9] Document/fix/warn about rebase incompatibilities and inconsistencies Phillip Wood
2018-06-07  5:07 ` [PATCH] git-rebase.sh: handle keep-empty like all other options Elijah Newren
2018-06-10 19:26   ` Phillip Wood
2018-06-11 14:42     ` Elijah Newren
2018-06-11 15:16       ` Phillip Wood
2018-06-11 16:08         ` Elijah Newren
2018-06-12  9:53           ` Phillip Wood
2018-06-07  5:08 ` [PATCH 1/2] t3418: add testcase showing problems with rebase -i and strategy options Elijah Newren
2018-06-07  5:08   ` [PATCH 2/2] Fix use of strategy options with interactive rebases Elijah Newren
2018-06-27  7:36   ` [PATCH v2 0/2] " Elijah Newren
2018-06-27  7:36     ` [PATCH v2 1/2] t3418: add testcase showing problems with rebase -i and strategy options Elijah Newren
2018-06-27  7:45       ` Eric Sunshine
2018-06-27  7:49         ` Elijah Newren
2018-06-27 16:54           ` Junio C Hamano
2018-06-27 17:27             ` Elijah Newren
2018-06-27 18:17               ` Johannes Sixt
2018-06-27 18:24                 ` Eric Sunshine
2018-06-27 18:34                 ` [PATCH v2 1/2] t3418: add testcase showing problems with rebase SZEDER Gábor
2018-06-27 19:20                 ` [PATCH v2 1/2] t3418: add testcase showing problems with rebase -i and strategy options Junio C Hamano
2018-06-27 19:23               ` Junio C Hamano
2018-06-27  7:36     ` [PATCH v2 2/2] Fix use of strategy options with interactive rebases Elijah Newren
2018-06-27 15:48     ` [PATCH v3 0/2] " Elijah Newren
2018-06-27 15:48       ` [PATCH v3 1/2] t3418: add testcase showing problems with rebase -i and strategy options Elijah Newren
2018-06-27 18:28         ` SZEDER Gábor
2018-07-11 10:56           ` SZEDER Gábor
2018-07-11 19:12             ` Elijah Newren
2018-06-27 15:48       ` [PATCH v3 2/2] Fix use of strategy options with interactive rebases Elijah Newren
2018-07-12 15:41         ` Johannes Schindelin
2018-07-13 15:51           ` Elijah Newren
2018-06-07 17:13 ` [RFC PATCH 0/3] Send more rebases through interactive machinery Elijah Newren
2018-06-07 17:13   ` [RFC PATCH 1/3] git-rebase, sequencer: add a --quiet option for the " Elijah Newren
2018-06-09 21:45     ` Johannes Schindelin
2018-06-09 23:05       ` Elijah Newren
2018-06-07 17:13   ` [RFC PATCH 2/3] rebase: Implement --merge via git-rebase--interactive Elijah Newren
2018-06-09 22:04     ` Johannes Schindelin
2018-06-10  1:14       ` Elijah Newren
2018-06-11  9:54         ` Phillip Wood
2018-06-07 17:13   ` [RFC PATCH 3/3] git-rebase.sh: make git-rebase--interactive the default Elijah Newren
2018-06-09 22:11     ` Johannes Schindelin
2018-06-10  1:31       ` Elijah Newren
2018-06-17 21:44         ` Johannes Schindelin
2018-06-20 16:27           ` Elijah Newren
2018-06-21 10:57             ` Johannes Schindelin
2018-06-21 15:36               ` Elijah Newren
2019-01-21 15:55                 ` Johannes Schindelin
2019-01-21 19:02                   ` Elijah Newren
2019-01-22 15:37                     ` Johannes Schindelin
2018-06-11 17:44 ` RFC: rebase inconsistency in 2.18 -- course of action? Junio C Hamano
2018-06-11 20:17   ` Elijah Newren

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