From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jonathan Nieder <jrnieder@gmail.com>
Subject: Re: [PATCH v8 23/44] fetch.c: change s_update_ref to use a ref
 transaction
Date: Fri, 16 May 2014 12:12:31 -0700
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References: <1400174999-26786-1-git-send-email-sahlberg@google.com>
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Cc: git@vger.kernel.org, mhagger@alum.mit.edu,
	Jeff King <peff@peff.net>
To: Ronnie Sahlberg <sahlberg@google.com>
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(+cc: peff for STORE_REF_ERROR_DF_CONFLICT expertise)
Ronnie Sahlberg wrote:

> --- a/builtin/fetch.c
> +++ b/builtin/fetch.c
> @@ -375,7 +375,7 @@ static int s_update_ref(const char *action,
[...]
> +	transaction = ref_transaction_begin();
> +	if (!transaction ||
> +	    ref_transaction_update(transaction, ref->name, ref->new_sha1,
> +				   ref->old_sha1, 0, check_old) ||
> +	    ref_transaction_commit(transaction, msg, NULL)) {
> +		ref_transaction_rollback(transaction);
>  		return errno == ENOTDIR ? STORE_REF_ERROR_DF_CONFLICT :
>  					  STORE_REF_ERROR_OTHER;
> +	}

I'd rather not rely on errno here (see the previous patch for why).
Is there some other way to distinguish the case where a ref couldn't
be created because there was a prefix of that ref in the way?

For example, maybe ref_transaction_commit could return a different
negative integer in this case.

Thanks,
Jonathan