patchcontrib/subtree: allow addition of remote branch with name not locally present

> cmd_add() attempts to check for the validity of refspec for the repository
> it is about to add as a subtree. It tries to do so before contacting the
> repository. If the refspec happens to exist locally (say 'master') then
> the test passes and the repo is fetched. If the refspec doesn't exist
> locally then the test fails and the remote repo is never contacted.
>
> Removing the tests still works as the git fetch command fails with the
> perfectly accurate error:
>
>   fatal: Couldn't find remote ref <refspec>
>
> Signed-off-by: Paul Campbell <pcampbell@carnegiecollege.ac.uk>
> ---
>
> I must confess to not understanding the comment preceding the
> rev-parse test. Given that it is against the rev-parse and not the
> cmd_add_repository call I'm assuming it can be removed.

>  contrib/subtree/git-subtree.sh | 8 --------
>  1 file changed, 8 deletions(-)
>
> diff --git a/contrib/subtree/git-subtree.sh b/contrib/subtree/git-subtree.sh
> index 8a23f58..9a38b18 100755
> --- a/contrib/subtree/git-subtree.sh
> +++ b/contrib/subtree/git-subtree.sh
> @@ -503,14 +503,6 @@ cmd_add()
>
>             "cmd_add_commit" "$@"
>         elif [ $# -eq 2 ]; then
> -           # Technically we could accept a refspec here but we're
> -           # just going to turn around and add FETCH_HEAD under the
> -           # specified directory.  Allowing a refspec might be
> -           # misleading because we won't do anything with any other
> -           # branches fetched via the refspec.
> -           git rev-parse -q --verify "$2^{commit}" >/dev/null ||
> -           die "'$2' does not refer to a commit"
> -
>             "cmd_add_repository" "$@"
>         else
>             say "error: parameters were '$@'"
> --
> 1.8.2.rc1

> Paul Campbell <pcampbell@kemitix.net> writes:
>
>> cmd_add() attempts to check for the validity of refspec for the repository
>> it is about to add as a subtree. It tries to do so before contacting the
>> repository. If the refspec happens to exist locally (say 'master') then
>> the test passes and the repo is fetched. If the refspec doesn't exist
>> locally then the test fails and the remote repo is never contacted.
>>
>> Removing the tests still works as the git fetch command fails with the
>> perfectly accurate error:
>>
>>   fatal: Couldn't find remote ref <refspec>
>>
>> Signed-off-by: Paul Campbell <pcampbell@carnegiecollege.ac.uk>
>> ---
>>
>> I must confess to not understanding the comment preceding the
>> rev-parse test. Given that it is against the rev-parse and not the
>> cmd_add_repository call I'm assuming it can be removed.
>
> This is contrib/ material and I do not use the command, so anything
> I say should be taken with a moderate amount of salt, but I think
> the comment is talking about _not_ accepting a full storing refspec,
> or worse yet wildcard, e.g.
>
>         refs/heads/topic:refs/remotes/origin/topic
>         refs/heads/*:refs/remotes/origin/*
>
> which will not make sense given that you are only adding a single
> commit via "cmd_add".  Also, if you have already fetched from the
> remote, "rev-parse $2^{commit}" at this point will protect against
> a typo by the end user.
>
> As you noticed, checking if $2 is a commit using rev-parse _before_
> fetching $2 from the remote repository is not a valid way to check
> against such errors.  So I tend to agree that removing the "die"
> will be a good idea.
>
> Typing "tipoc" when the user meant "topic" will error out at the
> "git fetch" done in cmd_add_repository, but that fetch will happily
> fetch and store whatever a refspec specifies, so you might want to
> replace the bogus "rev-parse before fetching" check to "reject
> refspec" with something else.