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

On Sun, Oct 6, 2013 at 4:27 PM, Stefan Beller
[off-list ref] wrote:

quoted

quoted

@@ -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