[PATCH 0/4] Use transactions for renames

[Ronnie Sahlberg <sahlberg@google.com>]

This series is based on ref-transactions-reflog
It is also available at
https://github.com/rsahlberg/git/tree/ref-transactions-rename

This series adds support to perform rename_ref as a single transaction for
both deleting/re-creating the ref and updating the reflog.

Since we no longer use rename() for the reflog changes we can now support
renames even if the reflogs are symlinks.

In order to make the delete-then-create fully atomic and also to ensure that
at no point in time is the object unreferenced we add support to do
deletes via the packed refs file to transaction_commit. For any refs that are
to be deleted, we first copy these refs to the packed refs file.
This allows us to immediately delete the loose ref files for those refs and
still being able to cancel/rollback the transaction.
Once all the changes are successfully updated we finally commit the packed
refs file a second time at which stage all the refs-to-be-deleted all
disappear in one atomic rename().

This allows us to perform transactions that delete multiple refs and have the
delete appear as one atomic transaction to any external observer.


Ronnie Sahlberg (4):
  refs.c: allow passing raw git_committer_info as email to
    _update_reflog
  refs.c: return error instead of dying when locking fails during
    transaction
  refs.c: use packed refs when deleting refs during a transaction
  refs.c: update rename_ref to use a transaction

 refs.c            | 308 +++++++++++++++++++++++++++++++++---------------------
 refs.h            |   1 +
 t/t3200-branch.sh |   7 --
 3 files changed, 192 insertions(+), 124 deletions(-)

-- 
2.0.0.583.g402232d