[PATCH 0/20] rs/ref-transaction-1 (Re: Transaction patch series overview)

> This series teaches the tag, replace, commit, cherry-pick,
> fast-import, checkout -b, branch, receive-pack, and http-fetch
> commands and all update_ref and delete_ref callers to use the ref
> transaction API instead of lock_ref_sha1.
>
> The main user-visible change should be some cosmetic changes to error
> messages.  The series also combines multiple ref updates into a single
> transaction in 'git http-fetch -w' and when writing tags in
> fast-import but otherwise doesn't change the granularity of
> transactions.
>
> Reviewed at https://code-review.googlesource.com/#/q/topic:ref-transaction-1
>
> ----------------------------------------------------------------
> Ronnie Sahlberg (20):
>       refs.c: change ref_transaction_create to do error checking and return status
>       refs.c: update ref_transaction_delete to check for error and return status
>       refs.c: make ref_transaction_begin take an err argument
>       refs.c: add transaction.status and track OPEN/CLOSED
>       tag.c: use ref transactions when doing updates
>       replace.c: use the ref transaction functions for updates
>       commit.c: use ref transactions for updates
>       sequencer.c: use ref transactions for all ref updates
>       fast-import.c: change update_branch to use ref transactions
>       branch.c: use ref transaction for all ref updates
>       refs.c: change update_ref to use a transaction
>       receive-pack.c: use a reference transaction for updating the refs
>       fast-import.c: use a ref transaction when dumping tags
>       walker.c: use ref transaction for ref updates
>       refs.c: make lock_ref_sha1 static
>       refs.c: remove the update_ref_lock function
>       refs.c: remove the update_ref_write function
>       refs.c: remove lock_ref_sha1
>       refs.c: make prune_ref use a transaction to delete the ref
>       refs.c: make delete_ref use a transaction