Re: [RFC] rebase: use @{upstream} if no upstream specified

[Martin von Zweigbergk <martin.von.zweigbergk@gmail.com>]

On Sat, Nov 13, 2010 at 4:51 AM, Yann Dirson <ydirson@free.fr> wrote:
> On Fri, Nov 12, 2010 at 09:55:49PM +0100, Martin von Zweigbergk wrote:
>
>> @@ -21,6 +21,10 @@ If <branch> is specified, 'git rebase' will perform an automatic
>>  `git checkout <branch>` before doing anything else.  Otherwise
>>  it remains on the current branch.
>>
>> +If <upstream> is not specified, the upstream configured in
>> +branch.<name>.remote and branch.<name>.merge options will be used; see
>> +linkgit:git-config[1] for details.
>> +
>
> Maybe make explicit that it will abort when no upstream is configured.

Will do.

>
>> @@ -416,9 +409,31 @@ esac
>>
>>  if test -z "$rebase_root"
>>  then
>> -     # The upstream head must be given.  Make sure it is valid.
>> -     upstream_name="$1"
>> -     shift
>> +     case "$#" in
>> +     0)      branch_name=$(git symbolic-ref -q HEAD) &&
>> +             upstream_name=$(git for-each-ref \
>> +                     --format='%(upstream)' ${branch_name})
>> +             if test -z $branch_name
>> +             then
>> +                     die "You are not currently on a branch, so I cannot use any
>> +'branch.<branchname>.merge' in your configuration file.
>> +Please specify which upstream branch you want to use on the command
>> +line and try again (e.g. 'git rebase <upstream branch>').
>> +See git-rebase(1) for details."
>> +             elif test -z $upstream_name
>> +             then
>> +                     die "You asked me to rebase without telling me which branch you
>> +want to rebase against, and 'branch.${branch_name#refs/heads/}.merge' in
>> +your configuration file does not tell me, either. Please
>> +specify which branch you want to use on the command line and
>> +try again (e.g. 'git rebase <upstream branch>').
>> +See git-rebase(1) for details."
>> +             fi
>> +             ;;
>> +     *)      upstream_name="$1"
>> +             shift
>> +             ;;
>> +     esac
>>       upstream=`git rev-parse --verify "${upstream_name}^0"` ||
>>       die "invalid upstream $upstream_name"
>>       unset root_flag
>
> What about simply checking if "rev-parse @{u}" succeeds, in which case
> we can use upstream_name=@{u} ?  If it fails, then we can do the work
> of finding where the config flaw is (and delegate this to a func).
> That would help keep the nominal code path short.

Will make sure to find out the error only when needed as you suggest.

I thought I would need the ref name to be able to walk the reflog if my
other propasal would be accepted (see
http://thread.gmane.org/gmane.comp.version-control.git/161381), but it
seems to work with @{u} as well. I just adapted the call from 'git pull'
(git-parse-remote.sh), but I guess I could use 'git rev-parse @{upstream}'
instead. It does seem more natural to me.

Maybe one of the guys on the CC list can advise?