From: Junio C Hamano <gitster@pobox•com>
To: Nicolas Sebrecht <nicolas.s.dev@gmx•fr>
Cc: Matthieu Moy <Matthieu.Moy@imag•fr>, git@vger•kernel.org
Subject: Re: [PATCH] Re: push: point to 'git pull' and 'git push --force' in case of non-fast forward
Date: Thu, 06 Aug 2009 14:32:13 -0700 [thread overview]
Message-ID: <7vprb8d3xe.fsf@alter.siamese.dyndns.org> (raw)
In-Reply-To: <20090806211610.GB12924@vidovic> (Nicolas Sebrecht's message of "Thu\, 6 Aug 2009 23\:16\:10 +0200")
Nicolas Sebrecht <nicolas.s.dev@gmx•fr> writes:
>> +Note about fast-forwards
>> +------------------------
>> +
>> +When an update changes a branch (or more in general, a ref) that used to
>> +point at commit A to point at another commit B, it is called a
>> +fast-forward update if and only if B is a descendant of A.
>> +
>> +In a fast-forward update from A to B, the set of commits that the original
>> +commit A built on top of is a subset of the commits the new commit B
>> +builds on top of. Hence, it does not lose any history.
>> +
>> +In contrast, a non-fast-forward update will lose history.
>
> I believe that this sentence a bit too much scaring for the beginner.
> There are two kinds of update (push and pull). We loose history only
> when pushing.
Three points that makes me think your suggested update is not appropriate
are:
(1) This patch is about git-push documentation;
(2) The opposite of git-push is git-fetch, not git-pull; and a non
fast-forward fetch does lose history if you start building on a
now-rewound tip of the remote tracking branch; and
(3) We _do_ want this section to be scary. We want the readers to be
fully aware of the implications before tempting them with the --force
option.
>> +Alternatively, you can rebase your change between X and B on top of A,
>> +with "git pull --rebase", and push the result back. The rebase will
>> +create a new commit D that builds the change between X and B on top of
>> +A.
>> +
>> +----------------
>> +
>> + B D
>> + / /
>> + ---X---A
>> +
>> +----------------
>
> Wouldn't "git pull --rebase" loose B? Shouldn't we have this
>
> ----------------
>
> D
> /
> ---X---A
>
> ----------------
>
> instead?
This makes B _loose_ (or, dangling), but does not _lose_ it. It is still
reachable from the reflog.
We could choose to not draw it for simplicity, or we could annotate it
like this for completeness (and to give a warm-fuzzy feeling to the reader
that nothing is lost).
----------------
branch@{1} (reachable from reflog)
branch
B D
/ /
---X------A
----------------
I don't know which is better. If we were printing in colours in the
documentation, I would keep B but draw it in light gray.
next prev parent reply other threads:[~2009-08-06 21:32 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-06 17:32 [PATCH] push: point to 'git pull' and 'git push --force' in case of non-fast forward Matthieu Moy
2009-08-06 20:04 ` Michael J Gruber
2009-08-07 19:21 ` Matthieu Moy
2009-08-07 19:46 ` Michael J Gruber
2009-08-06 20:15 ` Junio C Hamano
2009-08-06 21:16 ` [PATCH] " Nicolas Sebrecht
2009-08-06 21:32 ` Junio C Hamano [this message]
2009-08-07 19:37 ` [PATCH] " Matthieu Moy
2009-08-07 20:05 ` Junio C Hamano
2009-08-07 20:22 ` Matthieu Moy
2009-08-08 7:51 ` [PATCH v2] " Matthieu Moy
2009-08-08 8:35 ` Teemu Likonen
2009-08-08 15:22 ` Matthieu Moy
2009-08-08 16:25 ` Junio C Hamano
2009-08-08 22:23 ` [PATCH v2] " Nicolas Sebrecht
2009-08-09 18:35 ` [PATCH v2] " Matthieu Moy
2009-08-09 20:22 ` Junio C Hamano
2009-08-10 8:43 ` Matthieu Moy
2009-08-10 8:49 ` Junio C Hamano
2009-08-10 8:56 ` Matthieu Moy
2009-08-11 3:03 ` Nanako Shiraishi
2009-09-06 6:44 ` [RFC/PATCH 0/4] make helpful messages optional Jeff King
2009-09-06 6:46 ` [PATCH 1/4] push: fix english in non-fast-forward message Jeff King
2009-09-06 6:47 ` [PATCH 2/4] push: re-flow " Jeff King
2009-09-06 6:48 ` [PATCH 3/4] push: make non-fast-forward help message configurable Jeff King
2009-09-06 7:09 ` Junio C Hamano
2009-09-06 7:23 ` Jeff King
2009-09-06 7:30 ` Junio C Hamano
2009-09-06 7:32 ` Jeff King
2009-09-06 7:52 ` Junio C Hamano
2009-09-06 11:30 ` Sverre Rabbelier
2009-09-07 0:44 ` Nanako Shiraishi
2009-09-07 7:35 ` Johannes Sixt
2009-09-07 7:40 ` Mike Hommey
2009-09-07 8:24 ` Jeff King
2009-09-07 8:34 ` Matthieu Moy
2009-09-07 8:54 ` Jeff King
2009-09-07 11:20 ` Matthieu Moy
2009-09-08 18:51 ` Uri Okrent
2009-09-09 11:22 ` Jeff King
2009-09-09 11:26 ` [PATCH 0/2] configurable advice messages Jeff King
2009-09-09 11:38 ` [PATCH 1/2] push: make non-fast-forward help message configurable Jeff King
2009-09-09 19:06 ` Junio C Hamano
2009-09-09 20:39 ` Jeff King
2009-09-09 21:47 ` Junio C Hamano
2009-09-09 11:43 ` [PATCH 2/2] status: make "how to stage" messages optional Jeff King
2009-09-06 6:50 ` [PATCH 4/4] " Jeff King
2009-09-06 11:53 ` [RFC/PATCH 0/4] make helpful " Matthieu Moy
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