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From: Johan Herland <johan@herland.net>
To: Jeff King <peff@peff.net>
Cc: "yaneurabeya ." <yanegomi@gmail.com>,
	Git mailing list <git@vger.kernel.org>
Subject: Re: Fwd: Errors when diff'ing arbitrary upstream remotes are not intuitive if git pull --all hasn't been done
Date: Fri, 25 Oct 2013 09:03:41 +0200	[thread overview]
Message-ID: <CALKQrgc0u8TA4mXc+2Hv+Fyo8EYNuiickF_janeCxkzFn+xAvA@mail.gmail.com> (raw)
In-Reply-To: <20131025061459.GA23524@sigill.intra.peff.net>

On Fri, Oct 25, 2013 at 8:14 AM, Jeff King <peff@peff.net> wrote:
> On Fri, Oct 25, 2013 at 02:14:07AM -0400, Jeff King wrote:
>> >     Could this error message be improved for interactive commands by
>> > first checking to see whether or not the path starts with a remote,
>> > then recommend that the remote be pulled?
>>
>> That might be worth doing. We cannot definitely say the branch exists
>> without hitting the network (which we would not want to do in the
>> general case), but I think it is reasonable for git to give suggestions
>> (we could also give a "did you mean X..." for near-typos, as we do for
>> typo-ed commands like "git dif".
>>
>> If you do try it, please don't just check for the remote name, but
>> actually complete the right-hand side of the fetch refspec for each
>> remote. They are equivalent in the default config, but aren't
>> necessarily so (and there has been talk of adjusting the layout of
>> remote refspecs). I don't recall offhand what functions we have to help
>> you, but I believe Johan (cc'd) was working in this area recently and
>> might be able to say more.

Actually, I don't think there's much refspec stuff to be done here.
When running "git diff $remote/$branch", there are 3 possible
outcomes:

 - $remote is not a valid remote name, the user probably meant
something different (like "nested/branch"). The current error message
is fine.

 - $remote is a valid remote name, but $branch has not (yet) been
fetched from there. Suggest the user run "git fetch $remote"

 - $remote/$branch is a valid remote-tracking branch. The diff works! No errors.

So, AFAICS, the patch should simply:

 1. Split the input on the first '/' into $remote/$branch, and use the
preceding part ($remote) as a potential remote name, and the following
part ($branch) as a potential branch name. (Although it is
theoretically possible to have remote names containing slashes, I
don't think anybody uses them, and we have considered disallowing
them, mainly because of this very issue: it makes "$remote/$branch"
parsing (even more) ambiguous)

 2. See if a remote called $remote exists. If it does, suggest to the
user to run "git fetch $remote". If $remote does not exist, leave the
current error message in place.

Hope this helps,

...Johan

-- 
Johan Herland, <johan@herland.net>
www.herland.net

  reply	other threads:[~2013-10-25  7:03 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CAGH67wSf_RQigCmqRZKOpHdV9ELqE=078mkpwA4dfnUr=AvGVQ@mail.gmail.com>
2013-10-24 18:07 ` Fwd: Errors when diff'ing arbitrary upstream remotes are not intuitive if git pull --all hasn't been done yaneurabeya .
2013-10-25  6:14   ` Jeff King
2013-10-25  6:14     ` Jeff King
2013-10-25  7:03       ` Johan Herland [this message]
2013-10-25  7:10         ` Jeff King
2013-10-25  7:25           ` Johan Herland

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