Re: [PATCH v4 12/27] replace.c: use the ref transaction functions for updates

[Eric Sunshine <sunshine@sunshineco.com>]

On Mon, Apr 28, 2014 at 6:54 PM, Ronnie Sahlberg <sahlberg@google.com> wrote:
> Update replace.c to use ref transactions for updates.
>
> Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
> ---
>  builtin/replace.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/builtin/replace.c b/builtin/replace.c
> index b62420a..b037b29 100644
> --- a/builtin/replace.c
> +++ b/builtin/replace.c
> @@ -129,7 +129,8 @@ static int replace_object(const char *object_ref, const char *replace_ref,
>         unsigned char object[20], prev[20], repl[20];
>         enum object_type obj_type, repl_type;
>         char ref[PATH_MAX];
> -       struct ref_lock *lock;
> +       struct ref_transaction *transaction;
> +       struct strbuf err = STRBUF_INIT;
>
>         if (get_sha1(object_ref, object))
>                 die("Failed to resolve '%s' as a valid ref.", object_ref);
> @@ -157,11 +158,12 @@ static int replace_object(const char *object_ref, const char *replace_ref,
>         else if (!force)
>                 die("replace ref '%s' already exists", ref);
>
> -       lock = lock_any_ref_for_update(ref, prev, 0, NULL);
> -       if (!lock)
> -               die("%s: cannot lock the ref", ref);
> -       if (write_ref_sha1(lock, repl, NULL) < 0)
> -               die("%s: cannot update the ref", ref);
> +       transaction = ref_transaction_begin();
> +       if (!transaction ||
> +           ref_transaction_update(transaction, ref, repl, prev,
> +                                  0, !is_null_sha1(prev)) ||
> +           ref_transaction_commit(transaction, NULL, &err))
> +               die(_("%s: failed to replace ref: %s"), ref, err.buf);

Even though 'err' will be empty after this conditional, would
strbuf_release(&err) here be warranted to future-proof it? Today's
implementation of strbuf will not have allocated any memory, but
perhaps a future change might pre-allocate (unlikely though that is),
which would leak here.

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