Re: [PATCH 1/2] fetch: allow passing a transaction to `s_update_ref()`

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 8, 2021, 07:18 UTC
Message-ID: <xmqqsg7bj3qs.fsf@gitster.c.googlers.com>
In-Reply-To: <CAP8UFD1YxHGHLEHd_Bx1awSskjM6fHgM52nPWpTG2UHOmaOT9A@mail.gmail.com>

Christian Couder <christian.couder@gmail.com> writes:

Show 9 quoted lines

> Yeah, I think we also don't need the df_conflict variable, and I don't
> like the duplication of the following clean up code:
>
>         ref_transaction_free(transaction_to_free);
>         strbuf_release(&err);
>         free(msg);
>
> Patrick's patch didn't introduce them, but we might still want to get
> rid of them (see below).

Show 16 quoted lines

> diff --git a/builtin/fetch.c b/builtin/fetch.c
> index ecf8537605..8017fc19da 100644
> --- a/builtin/fetch.c
> +++ b/builtin/fetch.c
> @@ -581,6 +581,22 @@ static struct ref *get_ref_map(struct remote *remote,
> #define STORE_REF_ERROR_OTHER 1
> #define STORE_REF_ERROR_DF_CONFLICT 2
>
> +static int do_s_update_ref(struct ref_transaction *transaction,
> ...
> }
>
> static int refcol_width = 10;
> -------------------------------------------------------------------------
>
> After the above patch, Patrick's patch would become:

OK, I think the above as a preliminary clean-up would not hurt, but the "if the caller gave us NULL as the transaction, we are responsible for handling that bogosity" bit feels a bit too magical to my taste. I do understand that your intention is that it releaves the caller ...

Show 12 quoted lines

> @@ -613,9 +615,16 @@ static int s_update_ref(const char *action,
>                rla = default_rla.buf;
>        msg = xstrfmt("%s: %s", rla, action);
>
> -       transaction = ref_transaction_begin(&err);
> +       /*
> +        * If no transaction was passed to us, we manage the
> +        * transaction ourselves. Otherwise, we trust the caller to
> +        * handle the transaction lifecycle.
> +        */
> +       if (!transaction)
> +               transaction = our_transaction = ref_transaction_begin(&err);

... here from having to deal with NULL from ref_transaction_begin(), but I somehow do not see it as a code structure with a good taste.

I dunno.

Without that "if (!transaction ||" bit, I think your do_s_update_ref() is a good clean-up, though.

Thanks.

Show 21 quoted lines

> -       ret = do_s_update_ref(transaction, ref, check_old, &err, msg);
> +       ret = do_s_update_ref(transaction, ref, check_old, !!our_transaction,
> +                             &err, msg);
>        if (ret) {
>                error("%s", err.buf);
>                ret = (ret == TRANSACTION_NAME_CONFLICT)
> @@ -623,7 +632,7 @@ static int s_update_ref(const char *action,
>                        : STORE_REF_ERROR_OTHER;
>        }
>
> -       ref_transaction_free(transaction);
> +       ref_transaction_free(our_transaction);
>        strbuf_release(&err);
>        free(msg);
>        return ret;
> ...
> -------------------------------------------------------------------------
>
> You can find these patches, with Patrick as the author, there:
>
> https://gitlab.com/gitlab-org/gitlab-git/-/commits/cc-improve-s-update-ref/