Re: [PATCH] clone: do not segfault when specifying a nonexistent branch

[Duy Nguyen <pclouds@gmail.com>]

On Sun, Oct 6, 2013 at 4:27 PM, Stefan Beller
<stefanbeller@googlemail.com> wrote:
>>> @@ -688,7 +688,7 @@ static void write_refspec_config(const char* src_ref_prefix,
>>>
>>>         if (option_mirror || !option_bare) {
>>>                 if (option_single_branch && !option_mirror) {
>>> -                       if (option_branch) {
>>> +                       if (option_branch && our_head_points_at) {
>>>                                 if (strstr(our_head_points_at->name, "refs/tags/"))
>>>                                         strbuf_addf(&value, "+%s:%s", our_head_points_at->name,
>>>                                                 our_head_points_at->name);
>>
>> This prevents the segfault, but what about remote.*.fetch? Should we
>> setup standard refspec for fetch or..?
>>
>
> Looking at the code a few lines below, this comment comes up:
>
>         /*
>          * otherwise, the next "git fetch" will
>          * simply fetch from HEAD without updating
>          * any remote-tracking branch, which is what
>          * we want.
>          */
>
> This behavior was good for the case (!option_branch && !remote_head_points_at)
> Now we extend that behavior doing nothing to
>          ((!option_branch || !our_head_points_at) &&  !remote_head_points_at)
>
> I am not sure how to handle that case best. The user has given a non existing branch,
> so it doesn't make sense to track that branch, but only have that
> registered as a remote*.fetch?
>
> Reading the documentation enhancements of 31b808a
> (2012-09-20, clone --single: limit the fetch refspec to fetched branch), doesn't
> talk about this corner case. So maybe the remote.*.fetch shall be set, but no branch
> should be checked out, when running
> git clone --depth 1 -b test https://github.com/mitfik/coredump.git /tmp/coredump.git
>
> Does that make sense?

Looking further back to 86ac751 (Allow cloning an empty repository -
2009-01-23), the reason to allow cloning an empty repository is so
that the user does not have do manual configuration, so I agree with
your "maybe". git-clone.txt should have a short description about this
too in case somebody runs into this and cares enough to check the
document before heading to Stack Overflow.
-- 
Duy