[PATCH 0/4] Remove a user of extra_refs in clone

From: Michael Haggerty <mhagger@alum.mit.edu>

When cloning, write_remote_refs() creates local packed refs from the refs read from the remote repository. It does this by creating extra refs for the references then calling pack_refs() to bake the extra refs into the packed-refs file, then calling clear_extra_refs().

This is silly and relies on the kludgy extra_refs mechanism, which I want to get rid of. Instead, add a function call add_packed_ref() to the refs API, and use it to create packed refs (in the memory cache) directly. Then call pack_refs() as before to write the packed-refs file.

Because the new add_packed_ref() function allows references (perhaps many of them) to be added to an existing ref_array, it would be inefficient to re-sort the list after every addition. So instead, append new entries to the end of the ref_array and note that the array is unsorted. Then, before the ref_array is used, check if it is unsorted and sort it if necessary.

A side effect of this change is that the new packed references are left in the in-memory packed reference cache after the return from write_remote_refs() (whereas previously, the refs were stored as temporary extra refs that were purged before return from the function). I can't see any place in the following code where this would make a difference, but there is quite a bit of code there so it is hard to audit. Confirmation that this is OK would be welcome.

Michael Haggerty (4):
  pack_refs(): remove redundant check
  ref_array: keep track of whether references are sorted
  add_packed_ref(): new function in the refs API.
  write_remote_refs(): create packed (rather than extra) refs

 builtin/clone.c |    3 +--
 pack-refs.c     |    3 +--
 refs.c          |   39 ++++++++++++++++++++++++++++++++-------
 refs.h          |    6 ++++++
 4 files changed, 40 insertions(+), 11 deletions(-)