Re: [PATCH v4 15/27] fast-import.c: change update_branch to use ref transactions

[Eric Sunshine <sunshine@sunshineco.com>]

On Mon, Apr 28, 2014 at 6:54 PM, Ronnie Sahlberg <sahlberg@google.com> wrote:
> Change update_branch() to use ref transactions for updates.
>
> Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
> ---
>  fast-import.c | 20 ++++++++++++--------
>  1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/fast-import.c b/fast-import.c
> index fb4738d..300c8dc 100644
> --- a/fast-import.c
> +++ b/fast-import.c
> @@ -1678,36 +1678,40 @@ found_entry:
>  static int update_branch(struct branch *b)
>  {
>         static const char *msg = "fast-import";
> -       struct ref_lock *lock;
> +       struct ref_transaction *transaction;
>         unsigned char old_sha1[20];
> +       struct strbuf err = STRBUF_INIT;
>
>         if (is_null_sha1(b->sha1))
>                 return 0;
>         if (read_ref(b->name, old_sha1))
>                 hashclr(old_sha1);
> -       lock = lock_any_ref_for_update(b->name, old_sha1, 0, NULL);
> -       if (!lock)
> -               return error("Unable to lock %s", b->name);
>         if (!force_update && !is_null_sha1(old_sha1)) {
>                 struct commit *old_cmit, *new_cmit;
>
>                 old_cmit = lookup_commit_reference_gently(old_sha1, 0);
>                 new_cmit = lookup_commit_reference_gently(b->sha1, 0);
>                 if (!old_cmit || !new_cmit) {
> -                       unlock_ref(lock);
>                         return error("Branch %s is missing commits.", b->name);
>                 }
>
>                 if (!in_merge_bases(old_cmit, new_cmit)) {
> -                       unlock_ref(lock);
>                         warning("Not updating %s"
>                                 " (new tip %s does not contain %s)",
>                                 b->name, sha1_to_hex(b->sha1), sha1_to_hex(old_sha1));
>                         return -1;
>                 }
>         }
> -       if (write_ref_sha1(lock, b->sha1, msg) < 0)
> -               return error("Unable to update %s", b->name);
> +       transaction = ref_transaction_begin();
> +       if ((!transaction ||
> +           ref_transaction_update(transaction, b->name, b->sha1, old_sha1,
> +                                  0, 1)) ||
> +           (ref_transaction_commit(transaction, msg, &err) &&
> +            !(transaction = NULL))) {
> +               ref_transaction_rollback(transaction);
> +               return error("Unable to update branch %s: %s", b->name,
> +                            strbuf_detach(&err, NULL));

Iffy strbuf handling. The strbuf content is being leaked here whether
detached or not.

> +       }
>         return 0;
>  }
>
> --
> 1.9.1.528.g98b8868.dirty