[PATCH 0/4] forbid HEAD as a tagname

So, here is a cleaned up version, which ended up to be a 4-patch series.

 - The first two steps move code around to get rid of the "strbuf_"
   prefix from three misnamed helper functions that are more about
   refs than they are about string manipulation operations.  We now
   have:

   - copy_branchname() that copies a branchname while applying
     interpret_branch_name() like @{-1} for previous branch, @{u}
     for upstream, etc.

   - check_branch_ref() and check_tag_ref() that are allowed to be a
     bit stricter than check_refname_format(), e.g., to reject "HEAD"
     as the name of a branch or a tag.

 - The third step updates a test that assumes HEAD can be usable as
   the name of a tag, but the breakage the test tries to protect is
   not specific to any tagname.

 - The final step then forbids "git tag" from using "HEAD" as the
   name of a tag.

Junio C Hamano (4):
  refs: move ref name helpers around
  refs: drop strbuf_ prefix from helpers
  t5604: do not expect that HEAD is a valid tagname
  tag: "git tag" refuses to use HEAD as a tagname

 branch.c                   |  2 +-
 builtin/branch.c           | 10 ++++----
 builtin/check-ref-format.c |  2 +-
 builtin/checkout.c         |  2 +-
 builtin/merge.c            |  2 +-
 builtin/tag.c              | 13 +----------
 builtin/worktree.c         |  8 +++----
 gitweb/gitweb.perl         |  2 +-
 object-name.c              | 36 -----------------------------
 refs.c                     | 47 ++++++++++++++++++++++++++++++++++++++
 refs.h                     | 29 +++++++++++++++++++++++
 strbuf.h                   | 22 ------------------
 t/t5604-clone-reference.sh |  6 ++---
 t/t7004-tag.sh             |  6 +++++
 14 files changed, 100 insertions(+), 87 deletions(-)