Re: [PATCH v9 3/7] refs: new public ref function: safe_create_reflog

> The safe_create_reflog function creates a reflog, if it does not
> already exist.
> 
> The log_ref_setup function becomes private and gains a force_create
> parameter to force the creation of a reflog even if log_all_ref_updates
> is false or the refname is not one of the special refnames.
> 
> The new parameter also reduces the need to store, modify, and restore
> the log_all_ref_updates global before reflog creation.
> 
> In a moment, we will use this to add reflog creation commands to
> git-reflog.
> 
> Signed-off-by: David Turner <dturner@twopensource.com>
> ---
>  builtin/checkout.c | 14 +++++---------
>  refs.c             | 24 ++++++++++++++++++++----
>  refs.h             |  2 +-
>  3 files changed, 26 insertions(+), 14 deletions(-)
> 
> [...]
> diff --git a/refs.c b/refs.c
> index 2efa2dc..3277768 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -3128,8 +3128,13 @@ static int should_autocreate_reflog(const char *refname)
>  		!strcmp(refname, "HEAD");
>  }
>  
> -/* This function will fill in *err and return -1 on failure */
> -int log_ref_setup(const char *refname, struct strbuf *sb_logfile, struct strbuf *err)
> +/*
> + * Create a reflog for a ref.  If force_create = 0, the reflog will
> + * only be created for certain refs (those for which
> + * should_autocreate_reflog returns non-zero.  Otherwise, create it
> + * regardless of the ref name.  Fill in *err and return -1 on failure.
> + */
> +static int log_ref_setup(const char *refname, struct strbuf *sb_logfile, struct strbuf *err, int force_create)
>  {
>  	int logfd, oflags = O_APPEND | O_WRONLY;
>  	char *logfile;
> @@ -3138,7 +3143,7 @@ int log_ref_setup(const char *refname, struct strbuf *sb_logfile, struct strbuf
>  	logfile = sb_logfile->buf;
>  	/* make sure the rest of the function can't change "logfile" */
>  	sb_logfile = NULL;
> -	if (should_autocreate_reflog(refname)) {
> +	if (force_create || should_autocreate_reflog(refname)) {
>  		if (safe_create_leading_directories(logfile) < 0) {
>  			strbuf_addf(err, "unable to create directory for %s: "
>  				    "%s", logfile, strerror(errno));