Subject: Re: [PATCH 02/11] refs.c: change ref_transaction_update() to do error checking and return status

From: Michael Haggerty <[email-masked]>
Date: Sat, 19 Apr 2014 20:55:18 +0200

On 04/17/2014 09:46 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.
> 
> Signed-off-by: Ronnie Sahlberg <[email-masked]>
> ---
>  builtin/update-ref.c | 11 +++++++----
>  refs.c               |  9 +++++++--
>  refs.h               | 10 +++++-----
>  3 files changed, 19 insertions(+), 11 deletions(-)
> 
> diff --git a/builtin/update-ref.c b/builtin/update-ref.c
> index 405267f..12bfacc 100644
> --- a/builtin/update-ref.c
> +++ b/builtin/update-ref.c
> @@ -197,8 +197,10 @@ 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("failed transaction update for %s", refname);
> +
>  
>  	update_flags = 0;
>  	free(refname);
> @@ -286,8 +288,9 @@ 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 138ab70..da1761d 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -3327,19 +3327,24 @@ 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)
> +		return error("have_old is true but old_sha1 is NULL");

The function documentation doesn't seem to allow old_sha1 == NULL.  That
means that calling it that way is a bug, not an error.  Therefore, I
think this should result in

    die("BUG: have_old is true but old_sha1 is NULL");

>  
> +	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 892c5b6..00e4f7b 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.
>   */
> -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 Haggerty
[email-masked]
http://softwareswirl.blogspot.com/