Subject: Re: [PATCH 6/8] refs/reftable-backend: add support for symref updates

From: Patrick Steinhardt <[email-masked]>
Date: Tue, 2 Apr 2024 14:20:38 +0200

On Sat, Mar 30, 2024 at 11:46:21PM +0100, Karthik Nayak wrote:
> From: Karthik Nayak <[email-masked]>
> 
> Add support for transactional symbolic reference updates in the reftable
> backend.
> 
> While this commit is setting up the reftable-backend to support symrefs
> in transaction's. It will only be used in a consequent commit, when we
> wire up the `update-symref` option for `git-update-ref`.
> 
> Signed-off-by: Karthik Nayak <[email-masked]>
> ---
>  refs/reftable-backend.c | 23 +++++++++++++++++++----
>  1 file changed, 19 insertions(+), 4 deletions(-)
> 
> diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
> index 92f2803e90..35f2e8e050 100644
> --- a/refs/reftable-backend.c
> +++ b/refs/reftable-backend.c
> @@ -884,7 +884,7 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store,
>  			new_update = ref_transaction_add_update(
>  					transaction, "HEAD",
>  					u->flags | REF_LOG_ONLY | REF_NO_DEREF,
> -					&u->new_oid, &u->old_oid, u->msg, NULL);
> +					&u->new_oid, &u->old_oid, u->msg, u->symref_target);
>  			string_list_insert(&affected_refnames, new_update->refname);
>  		}
>  
> @@ -909,9 +909,11 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store,
>  
>  			/*
>  			 * There is no need to write the reference deletion
> -			 * when the reference in question doesn't exist.
> +			 * when the reference in question doesn't exist except
> +			 * when we want to create new symrefs.

Nit: it's not really an exception because it's not a reference deletion
in the first place when we write a symref.

Patrick

>  			 */
> -			 if (u->flags & REF_HAVE_NEW && !is_null_oid(&u->new_oid)) {
> +			if ((u->flags & REF_HAVE_NEW && !is_null_oid(&u->new_oid)) ||
> +			    u->flags & REF_UPDATE_SYMREF) {
>  				 ret = queue_transaction_update(refs, tx_data, u,
>  								&current_oid, err);
>  				 if (ret)
> @@ -963,7 +965,7 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store,
>  				 */
>  				new_update = ref_transaction_add_update(
>  						transaction, referent.buf, new_flags,
> -						&u->new_oid, &u->old_oid, u->msg, NULL);
> +						&u->new_oid, &u->old_oid, u->msg, u->symref_target);
>  				new_update->parent_update = u;
>  
>  				/*
> @@ -1026,6 +1028,7 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store,
>  		 */
>  		if ((u->type & REF_ISSYMREF) ||
>  		    (u->flags & REF_LOG_ONLY) ||
> +		    (u->flags & REF_UPDATE_SYMREF) ||
>  		    (u->flags & REF_HAVE_NEW && !oideq(&current_oid, &u->new_oid))) {
>  			ret = queue_transaction_update(refs, tx_data, u,
>  						       &current_oid, err);
> @@ -1187,6 +1190,18 @@ static int write_transaction_table(struct reftable_writer *writer, void *cb_data
>  			ret = reftable_writer_add_ref(writer, &ref);
>  			if (ret < 0)
>  				goto done;
> +		} else if (u->flags & REF_UPDATE_SYMREF) {
> +			struct write_create_symref_arg create  = {
> +				.refs = arg->refs,
> +				.stack = arg->stack,
> +				.refname = u->refname,
> +				.target = u->symref_target,
> +				.logmsg = u->msg,
> +			};
> +
> +			write_symref_with_log(writer, &create, ts);
> +			if (ret < 0)
> +				goto done;
>  		}
>  	}
>  
> -- 
> 2.43.GIT
>