Merge branch 'ao/check-resolve-ref-unsafe-result' into maint

"git commit", after making a commit, did not check for errors when
asking on what branch it made the commit, which has been correted.

* ao/check-resolve-ref-unsafe-result:
commit: check result of resolve_ref_unsafe

diff --cc builtin/commit.c
index d75b3805ea7fe3475564f337bf660d8155909445,b528290902da1153849e6cf4560488c553a1e38a..b2a6c7f100d82c4160c4bea6b4663af5459194cc
--- 1/builtin/commit.c
--- 2/builtin/commit.c
+++ b/builtin/commit.c
@@@ -1491,7 -1482,9 +1491,9 @@@ static void print_summary(const char *p
        rev.diffopt.break_opt = 0;
        diff_setup_done(&rev.diffopt);
  
 -      head = resolve_ref_unsafe("HEAD", 0, junk_oid.hash, NULL);
 +      head = resolve_ref_unsafe("HEAD", 0, NULL, NULL);
+       if (!head)
+               die_errno(_("unable to resolve HEAD after creating commit"));
        if (!strcmp(head, "HEAD"))
                head = _("detached HEAD");
        else