Subject: Re: [PATCH v6 08/42] refs.c: change ref_transaction_update() to do error checking and return status

From: Michael Haggerty <[email-masked]>
Date: Mon, 05 May 2014 15:08:17 +0200

On 05/01/2014 10:37 PM, Ronnie Sahlberg wrote:
> Update ref_transaction_update() do some basic error checking and return
> true on error. Update all callers to check ref_transaction_update() for error.
> There are currently no conditions in _update that will return error but there
> will be in the future.

I would change s/true/non-zero/, because error return values are not
just boolean values; the error values sometimes encode the type of error
that occurred.

> 
> Signed-off-by: Ronnie Sahlberg <[email-masked]>
> ---
>  builtin/update-ref.c | 10 ++++++----
>  refs.c               |  9 +++++++--
>  refs.h               | 10 +++++-----
>  3 files changed, 18 insertions(+), 11 deletions(-)
> 
> diff --git a/builtin/update-ref.c b/builtin/update-ref.c
> index 2bef2a0..59c4d6b 100644
> --- a/builtin/update-ref.c
> +++ b/builtin/update-ref.c
> @@ -197,8 +197,9 @@ static const char *parse_cmd_update(struct strbuf *input, const char *next)
>  	if (*next != line_termination)
>  		die("update %s: extra input: %s", refname, next);
>  
> -	ref_transaction_update(transaction, refname, new_sha1, old_sha1,
> -			       update_flags, have_old);
> +	if (ref_transaction_update(transaction, refname, new_sha1, old_sha1,
> +				   update_flags, have_old))
> +		die("update %s: failed", refname);
>  
>  	update_flags = 0;
>  	free(refname);
> @@ -286,8 +287,9 @@ static const char *parse_cmd_verify(struct strbuf *input, const char *next)
>  	if (*next != line_termination)
>  		die("verify %s: extra input: %s", refname, next);
>  
> -	ref_transaction_update(transaction, refname, new_sha1, old_sha1,
> -			       update_flags, have_old);
> +	if (ref_transaction_update(transaction, refname, new_sha1, old_sha1,
> +				   update_flags, have_old))
> +		die("failed transaction update for %s", refname);
>  
>  	update_flags = 0;
>  	free(refname);
> diff --git a/refs.c b/refs.c
> index 308e13e..1a903fb 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -3333,19 +3333,24 @@ static struct ref_update *add_update(struct ref_transaction *transaction,
>  	return update;
>  }
>  
> -void ref_transaction_update(struct ref_transaction *transaction,
> +int ref_transaction_update(struct ref_transaction *transaction,
>  			    const char *refname,
>  			    const unsigned char *new_sha1,
>  			    const unsigned char *old_sha1,
>  			    int flags, int have_old)
>  {
> -	struct ref_update *update = add_update(transaction, refname);
> +	struct ref_update *update;
> +
> +	if (have_old && !old_sha1)
> +		die("have_old is true but old_sha1 is NULL");

This new check is orthogonal to the rest of the patch, isn't it?

>  
> +	update = add_update(transaction, refname);
>  	hashcpy(update->new_sha1, new_sha1);
>  	update->flags = flags;
>  	update->have_old = have_old;
>  	if (have_old)
>  		hashcpy(update->old_sha1, old_sha1);
> +	return 0;
>  }
>  
>  void ref_transaction_create(struct ref_transaction *transaction,
> diff --git a/refs.h b/refs.h
> index bc7715e..0364a3e 100644
> --- a/refs.h
> +++ b/refs.h
> @@ -237,11 +237,11 @@ void ref_transaction_rollback(struct ref_transaction *transaction);
>   * that the reference should have had before the update, or zeros if
>   * it must not have existed beforehand.
>   */

Please update the docstring above to explain the return value.

> -void ref_transaction_update(struct ref_transaction *transaction,
> -			    const char *refname,
> -			    const unsigned char *new_sha1,
> -			    const unsigned char *old_sha1,
> -			    int flags, int have_old);
> +int ref_transaction_update(struct ref_transaction *transaction,
> +			   const char *refname,
> +			   const unsigned char *new_sha1,
> +			   const unsigned char *old_sha1,
> +			   int flags, int have_old);
>  
>  /*
>   * Add a reference creation to transaction.  new_sha1 is the value
> 

Michael

-- 
Michael Haggerty
[email-masked]
http://softwareswirl.blogspot.com/