From: "Stephen J. Turnbull" <stephen@xemacs.org>
To: David Engster <deng@randomsample.de>
Cc: Eli Zaretskii <eliz@gnu.org>, emacs-devel@gnu.org
Subject: Re: master c6f03ed: Fix a problem in url.el without GnuTLS
Date: Thu, 18 Dec 2014 13:55:26 +0900 [thread overview]
Message-ID: <87wq5pd0ap.fsf@uwakimon.sk.tsukuba.ac.jp> (raw)
In-Reply-To: <87egrynhcd.fsf@engster.org>
David Engster writes:
> up anew. If HEAD is your merge commit, this would mean doing
>
> git branch -D branchname
> git branch branchname HEAD^2
>
> (You have to delete with '-D', since Git won't see your non-rebased
> branch as merged...).
Aside: can't you do this in one operation with "git branch -f
branchname HEAD^2"? (Real question, I don't understand your reference
to "seeing ... branch as merged". The docs seem to indicate it should
work.)
> > That'd lose too much information, so I'd like to avoid that if
> > possible.
>
> What kind of information do you mean here? I'm guessing you want to see
> the merges from master and how you reacted to them? You're right that
> this will be lost.
I think this is the crucial question. git documents are very good at
explaining implementations, but people have a habit of deciding what
they think a command does based on its name. That matters a little
for Eli, and a lot for GitForEmacsDevs.
We really need to see what DAG Eli wants to construct. Then we can
see how to create it using primitives, and finally see if there's a
reasonable shortcut by using more complex commands and appropriate
options (where "reasonable" is defined "Eli feels comfortable with it
for the purposes he has in mind" -- we have to ask Eli :-).
> OK, let me try to summarize what I think are the two main conflicting
> requirements:
>
> . You want to handle merges of local feature branches and public
> branches (like 'emacs-24') in the same way.
>
> I think this one is the strongest requirement, since it means you simply
> cannot use 'rebase' in any way. Also, you've pointed out several other
> problems with 'rebase', like loosing the "real" history of a feature
> branch, and accidental merging of rebased commits.
>
> Therefore, I think a purely merge-based workflow is really the only
> option for you, which however brings us to
>
> . You want to keep a clear history of 'mainline', meaning you want to
> achieve a similar log view to that from Bazaar, using 'git log
> --first-parent'.
>
> This conflicts with how Git orders the parents of a merge. The first
> parent is always the tip of the branch you're currently on. And since
> you do 'git pull' while being on your local master, that will be the
> first parent.
I don't see a conflict here. What I do see is an ambiguity in the
discription of entry conditions. If you bzr-think, on a feature
branch the "local master" is likely to be the feature branch.[1] That
is, the workflow is
git clone git:emacs ./feature-1
cd feature-1
emacs file1 ...
git commit
git pull git:emacs # we've just swapped master and
# origin/master, ie, the public mainline,
# when we push mainline is nonlinear
without actually defining a branch. I agree this is problematic.
It's more complex, but if you do
git clone git:emacs ./feature-1
cd feature-1
git checkout -b feature-1
emacs file1 ...
git commit
git pull git:emacs # origin/master contains public mainline
# feature-1 contains local mainline
To push to public:
git checkout master
git push # public mainline is preserved
git checkout feature-1 # #### these three commands are error-prone
AFAICS this is what you need to do for emacs-24, too. The problems
are (1) a convenient discipline for those last three commands and (2)
recovery from failed push due to concurrent development. I think that
one way to provide convenience and discipline would be to (a) require
that the feature branch workspace be located in a directory with the
same name as the feature branch, and (b) provide git-pull-emacs and
git-push-emacs scripts that check for $(basename $cwd) == feature-name
as a precondition. I don't know about the failed merge recovery,
though.
> Of course, while *you* can take care in keeping the correct ordering of
> mainline, others won't do that (I guess most are not even aware of this
> issue),
All bzr fans are aware of it though. It's an important part of
Bazaar's identity in VCS space. The problem will be git users who are
used to a spaghetti DAG.
> One could implement a git hook that checks for a linear git history
> of mainline and that rejects pushes otherwise, but I guess Stefan
> isn't very inclined to agree to that.
My impression is that Stefan is not inclined to encourage work on this
problem; he thinks it's a waste of time. I think he'd come around
quickly if presented with either another problem that would be solved
by the same workflow that preserves linear mainline, or a
"sufficiently convenient" workflow that preserves linear mainline. I
don't intend to speak for Stefan, just to encourage you to not give up
on the idea of a hook before you've clarified the point with him.
Footnotes:
[1] I think Eli means that in his feature branch workspace he uses a
branch named for the feature rather than master, but we need to be
clear about this.
next prev parent reply other threads:[~2014-12-18 4:55 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20141211155740.11916.1584@vcs.savannah.gnu.org>
[not found] ` <E1Xz67Y-00036o-Vf@vcs.savannah.gnu.org>
2014-12-11 16:47 ` master c6f03ed: Fix a problem in url.el without GnuTLS Leo Liu
2014-12-11 18:08 ` Eli Zaretskii
2014-12-11 23:00 ` Ted Zlatanov
2014-12-12 9:23 ` Eli Zaretskii
2014-12-12 13:24 ` Ted Zlatanov
2014-12-12 14:28 ` Eli Zaretskii
2014-12-12 16:06 ` Stefan Monnier
2014-12-13 0:25 ` Ted Zlatanov
2014-12-13 0:28 ` Lars Magne Ingebrigtsen
2014-12-13 1:25 ` Ted Zlatanov
2014-12-13 8:04 ` Eli Zaretskii
2014-12-13 10:16 ` David Engster
2014-12-18 22:38 ` David Engster
2014-12-19 8:50 ` Eli Zaretskii
2014-12-13 9:04 ` David Engster
2014-12-13 9:50 ` David Engster
2014-12-13 13:19 ` Ted Zlatanov
2014-12-13 14:13 ` David Engster
2014-12-13 14:25 ` Ted Zlatanov
2014-12-13 15:18 ` Eli Zaretskii
2014-12-13 19:44 ` David Engster
2014-12-13 19:59 ` Eli Zaretskii
2014-12-13 22:00 ` Dmitry Gutov
2014-12-14 3:36 ` Eli Zaretskii
2014-12-13 23:13 ` David Engster
2014-12-14 16:09 ` Eli Zaretskii
2014-12-14 16:37 ` Ted Zlatanov
2014-12-14 16:55 ` Eli Zaretskii
2014-12-14 17:00 ` Ted Zlatanov
2014-12-14 23:21 ` Stefan Monnier
2014-12-14 17:46 ` Paul Eggert
2014-12-14 17:50 ` Eli Zaretskii
2014-12-14 18:28 ` Ted Zlatanov
2014-12-14 19:41 ` David Engster
2014-12-14 21:40 ` David Engster
2014-12-15 3:47 ` Eli Zaretskii
2014-12-15 20:39 ` David Engster
2014-12-16 19:42 ` Eli Zaretskii
2014-12-17 9:58 ` Steinar Bang
2014-12-17 10:52 ` Steinar Bang
2014-12-17 15:36 ` Eli Zaretskii
2014-12-17 15:35 ` Eli Zaretskii
2014-12-17 20:37 ` David Engster
2014-12-18 4:55 ` Stephen J. Turnbull [this message]
2014-12-18 15:39 ` Eli Zaretskii
2014-12-18 20:00 ` Steinar Bang
2014-12-18 20:40 ` Eli Zaretskii
2014-12-19 8:09 ` Steinar Bang
2014-12-19 9:16 ` Eli Zaretskii
2014-12-19 10:33 ` Steinar Bang
2014-12-18 21:18 ` David Engster
2014-12-18 15:38 ` Eli Zaretskii
2014-12-18 19:46 ` Steinar Bang
2014-12-18 20:35 ` Eli Zaretskii
2014-12-19 6:07 ` Yuri Khan
2014-12-19 7:57 ` Steinar Bang
2014-12-19 9:09 ` Eli Zaretskii
2014-12-18 20:46 ` David Engster
2014-12-14 22:42 ` Stefan Monnier
2014-12-15 3:37 ` Eli Zaretskii
2014-12-15 4:46 ` Stefan Monnier
2014-12-12 20:46 ` Lars Magne Ingebrigtsen
2014-12-12 0:30 ` Leo Liu
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