From: Junio C Hamano <gitster@pobox.com>
To: Johan Herland <johan@herland.net>
Cc: git@vger.kernel.org
Subject: Re: [RFD] Making "git push [--force/--delete]" safer?
Date: Wed, 03 Jul 2013 01:49:56 -0700 [thread overview]
Message-ID: <7vli5ogh8r.fsf@alter.siamese.dyndns.org> (raw)
In-Reply-To: <CALKQrgdovWTd50LVDnNR+BhurWgSCKkhr88wCo01VZF3sd5PNg@mail.gmail.com> (Johan Herland's message of "Wed, 3 Jul 2013 08:34:25 +0200")
Johan Herland <johan@herland.net> writes:
> Overnight, it occured to me that --force-if-expected could be
> simplified by leveraging the existing --force option; for the above
> two examples, respectively:
>
> $ git push --force --expect
> # validate foo @ origin == @{upstream} before pushing
>
> and
>
> $ git push --force --expect=refs/original/foo my_remote HEAD:foo
> # validate foo @ my_remote == refs/original/foo before pushing
First, on the name.
I do not think either "--validate" or "--expect" is particularly a
good one. The former lets this feature squat on a good name that
covers a much broader spectrum, forbidding people from adding other
kinds of validation later. "--expect" is slightly less bad in that
sense; saying "we expect this" does imply "otherwise it is an
unexpected situation and we would fail", but the name still does not
feel ideal.
What is the essense of compare-and-swap? Perhaps we can find a good
word by thinking that question through.
To me, it is a way to implement a "lock" on the remote ref without
actually taking a lock (which would leave us open for a stale lock),
and this "lock"-ness is what we want in order to guarantee safety.
So we could perhaps call it "--lockref"?
I'll leave the name open but tentatively use this name in the
following, primarily to see how well it sits on the command line
examples.
Then on the semantics/substance.
I had quite a similar thought as you had while reading your initial
response. In the most generic form, we would want to be able to
pass necessary information fully via the option, i.e.
--lockref=theirRefName:expectedValue
but when the option is spelled without details, we could fill in the
default values by making a reasonable guess of what the user could
have meant. If we only have --lockref without refname nor value,
then we will enable the safety for _all_ refs that we are going to
update during this push. If we have --lockref=theirRefName without
the expected value for that ref, we will enable the safety only for
the ref (you can give more than one --lockref=theirRefName), and
guess what value we should expect. If we have a fully specified
option, we do not have to guess the value.
And for the expected value, when we have a tracking branch for the
branch at the remote we are trying to update, its value is a very
good guess of what the user meant.
Note, however, that this is very different from @{upstream}.
You could be pushing a branch "frotz", that is configured to
integrate with "master" taken from "origin", but
(1) to a branch different from "master" of "origin", e.g.
$ git push --lockref origin frotz:nitfol
$ git push --lockref origin :nitfol ;# deleting
(2) even to a branch of a remote that is different from "origin",
e.g.
$ git push --lockref xyzzy frotz:nitfol
$ git push --lockref xyzzy :nitfol ;# deleting
Even in these case, if you have a remote tracking branch for the
destination (i.e. you have refs/remotes/origin/nitfol in case (1) or
refs/remotes/xyzzy/nitfol in case (2) to be updated by fetching from
origin or xyzzy), we can and should use that value as the default.
There is no room for frotz@{upstream} (or @{upstream} of the current
branch) to get in the picture.
Except when you happen to be pushing with "push.default = upstream",
that is. But that is a natural consequence of the more generic
check with "our remote tracking branch of the branch we are updating
at the remote" rule.
next prev parent reply other threads:[~2013-07-03 8:52 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-02 20:57 [RFD] Making "git push [--force/--delete]" safer? Junio C Hamano
2013-07-02 22:55 ` Johan Herland
2013-07-03 6:34 ` Johan Herland
2013-07-03 8:49 ` Junio C Hamano [this message]
2013-07-03 10:00 ` Johan Herland
2013-07-03 10:06 ` Jonathan del Strother
2013-07-03 10:11 ` Johan Herland
2013-07-03 10:50 ` Michael Haggerty
2013-07-03 12:06 ` Johannes Sixt
2013-07-03 19:53 ` Junio C Hamano
2013-07-04 5:37 ` Johannes Sixt
2013-07-04 5:46 ` Junio C Hamano
2013-07-03 19:50 ` Junio C Hamano
2013-07-03 20:18 ` Junio C Hamano
2013-07-03 19:48 ` Junio C Hamano
2013-07-09 19:53 ` [PATCH 0/7] safer "push --force" with compare-and-swap Junio C Hamano
2013-07-09 19:53 ` [PATCH 1/7] cache.h: move remote/connect API out of it Junio C Hamano
2013-07-09 19:53 ` [PATCH 2/7] builtin/push.c: use OPT_BOOL, not OPT_BOOLEAN Junio C Hamano
2013-07-09 19:53 ` [PATCH 3/7] push: beginning of compare-and-swap "force/delete safety" Junio C Hamano
2013-07-09 19:53 ` [PATCH 4/7] remote.c: add command line option parser for --lockref Junio C Hamano
2013-07-16 22:13 ` John Keeping
2013-07-17 17:06 ` Junio C Hamano
2013-07-17 17:09 ` Junio C Hamano
2013-07-09 19:53 ` [PATCH 5/7] push --lockref: implement logic to populate old_sha1_expect[] Junio C Hamano
2013-07-09 19:53 ` [PATCH 6/7] t5533: test "push --lockref" Junio C Hamano
2013-07-09 19:53 ` [PATCH 7/7] push: document --lockref Junio C Hamano
2013-07-09 20:17 ` Aaron Schrab
2013-07-09 20:39 ` Junio C Hamano
2013-07-09 20:24 ` Johannes Sixt
2013-07-09 20:37 ` Junio C Hamano
2013-07-09 20:55 ` Johannes Sixt
2013-07-09 22:09 ` Junio C Hamano
2013-07-09 23:08 ` Junio C Hamano
2013-07-11 21:10 ` Johannes Sixt
2013-07-11 21:57 ` Junio C Hamano
2013-07-11 22:14 ` Junio C Hamano
2013-07-12 17:21 ` Johannes Sixt
2013-07-12 17:40 ` Junio C Hamano
2013-07-12 20:00 ` Johannes Sixt
2013-07-12 21:19 ` Junio C Hamano
2013-07-13 6:52 ` Johannes Sixt
2013-07-13 18:14 ` Junio C Hamano
2013-07-13 20:08 ` Junio C Hamano
2013-07-13 21:11 ` Johannes Sixt
2013-07-14 14:28 ` John Keeping
2013-07-13 20:17 ` Johannes Sixt
2013-07-14 19:17 ` Junio C Hamano
2013-07-14 20:21 ` Johannes Sixt
2013-07-14 20:34 ` Jonathan Nieder
2013-07-14 20:49 ` Jonathan Nieder
2013-07-14 20:59 ` Johannes Sixt
2013-07-14 21:28 ` Jonathan Nieder
2013-07-15 4:10 ` Junio C Hamano
2013-07-15 4:44 ` Jonathan Nieder
2013-07-15 15:37 ` Junio C Hamano
2013-07-15 20:30 ` Johannes Sixt
2013-07-15 3:50 ` Junio C Hamano
2013-07-15 15:47 ` Default expectation of --lockref Junio C Hamano
2013-07-15 20:27 ` [PATCH 7/7] push: document --lockref Johannes Sixt
2013-07-09 21:37 ` Marc Branchaud
2013-07-09 20:27 ` Michael Haggerty
2013-07-09 20:42 ` Junio C Hamano
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