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From: Junio C Hamano <gitster@pobox.com>
To: Patrick Steinhardt <ps@pks.im>
Cc: git@vger.kernel.org, Christian Couder <christian.couder@gmail.com>
Subject: Re: [PATCH v2 2/4] fetch: refactor `s_update_ref` to use common exit path
Date: Fri, 08 Jan 2021 15:50:00 -0800	[thread overview]
Message-ID: <xmqqim87gf9z.fsf@gitster.c.googlers.com> (raw)
In-Reply-To: <718a8bf5d7a0ed92c3004991a42419279ff38253.1610107599.git.ps@pks.im> (Patrick Steinhardt's message of "Fri, 8 Jan 2021 13:11:19 +0100")

Patrick Steinhardt <ps@pks.im> writes:

> @@ -598,30 +598,33 @@ static int s_update_ref(const char *action,
>  	msg = xstrfmt("%s: %s", rla, action);
>  
>  	transaction = ref_transaction_begin(&err);
> -	if (!transaction ||
> -	    ref_transaction_update(transaction, ref->name,
> -				   &ref->new_oid,
> -				   check_old ? &ref->old_oid : NULL,
> -				   0, msg, &err))
> -		goto fail;
> +	if (!transaction) {
> +		ret = STORE_REF_ERROR_OTHER;
> +		goto out;
> +	}
> +
> +	ret = ref_transaction_update(transaction, ref->name, &ref->new_oid,
> +				     check_old ? &ref->old_oid : NULL,
> +				     0, msg, &err);
> +	if (ret) {
> +		ret = STORE_REF_ERROR_OTHER;
> +		goto out;
> +	}

The above certainly got cleaner thanks to Christian's suggestion,
but I wonder why

	transaction = ref_transaction_begin(&err);
	if (!transaction ||
	    ref_transaction_update(transaction, ref->name,
				   &ref->new_oid,
				   check_old ? &ref->old_oid : NULL,
				   0, msg, &err)) {
		ret = STORE_REF_ERROR_OTHER;
		goto out;
	}

shouldn't be sufficient.

>  	ret = ref_transaction_commit(transaction, &err);
>  	if (ret) {
> -		df_conflict = (ret == TRANSACTION_NAME_CONFLICT);
> -		goto fail;
> +		ret = (ret == TRANSACTION_NAME_CONFLICT) ? STORE_REF_ERROR_DF_CONFLICT
> +							 : STORE_REF_ERROR_OTHER;
> +		goto out;
>  	}
> 
> +out:
>  	ref_transaction_free(transaction);

It is a bit funny to see a goto that jumps to the label without
having anything else in between, but we know we will be adding more
code just before the "out:" label, so it is a good preliminary
preparation.

I think a variant that is much easier to follow would be to write
like this instead:

	switch (ref_transaction_commit(transaction, &err)) {
        case 0: /* happy */
		break;
	case TRANSACTION_NAME_CONFLICT:
		ret = STORE_REF_ERROR_DF_CONFLICT;
		goto out;
	default:
		ret = STORE_REF_ERROR_OTHER;
		goto out;
	}

> +	if (ret)
> +		error("%s", err.buf);

OK.

>  	strbuf_release(&err);
>  	free(msg);
> -	return 0;
> -fail:
> -	ref_transaction_free(transaction);
> -	error("%s", err.buf);
> -	strbuf_release(&err);
> -	free(msg);
> -	return df_conflict ? STORE_REF_ERROR_DF_CONFLICT
> -			   : STORE_REF_ERROR_OTHER;
> +	return ret;
>  }
>  
>  static int refcol_width = 10;

THanks.

  reply	other threads:[~2021-01-08 23:52 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-07 13:51 [PATCH 0/2] fetch: implement support for atomic reference updates Patrick Steinhardt
2021-01-07 13:51 ` [PATCH 1/2] fetch: allow passing a transaction to `s_update_ref()` Patrick Steinhardt
2021-01-07 22:59   ` Junio C Hamano
2021-01-08  0:45     ` Christian Couder
2021-01-08  7:18       ` Junio C Hamano
2021-01-07 13:51 ` [PATCH 2/2] fetch: implement support for atomic reference updates Patrick Steinhardt
2021-01-08  0:19   ` Junio C Hamano
2021-01-08 12:11 ` [PATCH v2 0/4] " Patrick Steinhardt
2021-01-08 12:11   ` [PATCH v2 1/4] fetch: extract writing to FETCH_HEAD Patrick Steinhardt
2021-01-08 23:40     ` Junio C Hamano
2021-01-11 10:26       ` Patrick Steinhardt
2021-01-11 19:24         ` Junio C Hamano
2021-01-08 12:11   ` [PATCH v2 2/4] fetch: refactor `s_update_ref` to use common exit path Patrick Steinhardt
2021-01-08 23:50     ` Junio C Hamano [this message]
2021-01-11 10:28       ` Patrick Steinhardt
2021-01-08 12:11   ` [PATCH v2 3/4] fetch: allow passing a transaction to `s_update_ref()` Patrick Steinhardt
2021-01-08 23:53     ` Junio C Hamano
2021-01-08 12:11   ` [PATCH v2 4/4] fetch: implement support for atomic reference updates Patrick Steinhardt
2021-01-09  0:05     ` Junio C Hamano
2021-01-11 10:42       ` Patrick Steinhardt
2021-01-11 19:47         ` Junio C Hamano
2021-01-12 12:22           ` Patrick Steinhardt
2021-01-12 12:29             ` Patrick Steinhardt
2021-01-12 19:19             ` Junio C Hamano
2021-01-11 11:05 ` [PATCH v3 0/5] " Patrick Steinhardt
2021-01-11 11:05   ` [PATCH v3 1/5] fetch: extract writing to FETCH_HEAD Patrick Steinhardt
2021-01-11 23:16     ` Junio C Hamano
2021-01-11 11:05   ` [PATCH v3 2/5] fetch: use strbuf to format FETCH_HEAD updates Patrick Steinhardt
2021-01-11 11:10     ` Patrick Steinhardt
2021-01-11 11:17     ` Christian Couder
2021-01-11 23:21     ` Junio C Hamano
2021-01-11 11:05   ` [PATCH v3 3/5] fetch: refactor `s_update_ref` to use common exit path Patrick Steinhardt
2021-01-11 11:05   ` [PATCH v3 4/5] fetch: allow passing a transaction to `s_update_ref()` Patrick Steinhardt
2021-01-11 11:05   ` [PATCH v3 5/5] fetch: implement support for atomic reference updates Patrick Steinhardt
2021-01-12  0:04   ` [PATCH v3 0/5] " Junio C Hamano
2021-01-12 12:27 ` [PATCH v4 " Patrick Steinhardt
2021-01-12 12:27   ` [PATCH v4 1/5] fetch: extract writing to FETCH_HEAD Patrick Steinhardt
2021-01-12 12:27   ` [PATCH v4 2/5] fetch: use strbuf to format FETCH_HEAD updates Patrick Steinhardt
2021-01-12 12:27   ` [PATCH v4 3/5] fetch: refactor `s_update_ref` to use common exit path Patrick Steinhardt
2021-01-12 12:27   ` [PATCH v4 4/5] fetch: allow passing a transaction to `s_update_ref()` Patrick Steinhardt
2021-01-12 12:27   ` [PATCH v4 5/5] fetch: implement support for atomic reference updates Patrick Steinhardt

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