Re: [PATCH v3 2/6] branch.c: replace `git_config()` with `git_config_get_string()`

[Junio C Hamano <gitster@pobox.com>]

Tanay Abhra <tanayabh@gmail.com> writes:

> Use `git_config_get_string()` instead of `git_config()` to take advantage of
> the config-set API which provides a cleaner control flow.
>
> Signed-off-by: Tanay Abhra <tanayabh@gmail.com>
> ---
>  branch.c | 24 ++++--------------------
>  1 file changed, 4 insertions(+), 20 deletions(-)
>
> diff --git a/branch.c b/branch.c
> index 46e8aa8..827307f 100644
> --- a/branch.c
> +++ b/branch.c
> @@ -140,33 +140,17 @@ static int setup_tracking(const char *new_ref, const char *orig_ref,
>  	return 0;
>  }
>  
> -struct branch_desc_cb {
> -	const char *config_name;
> -	const char *value;
> -};
> -
> -static int read_branch_desc_cb(const char *var, const char *value, void *cb)
> -{
> -	struct branch_desc_cb *desc = cb;
> -	if (strcmp(desc->config_name, var))
> -		return 0;
> -	free((char *)desc->value);
> -	return git_config_string(&desc->value, var, value);
> -}
> -
>  int read_branch_desc(struct strbuf *buf, const char *branch_name)
>  {
> -	struct branch_desc_cb cb;
> +	const char *v = NULL;
>  	struct strbuf name = STRBUF_INIT;
>  	strbuf_addf(&name, "branch.%s.description", branch_name);
> -	cb.config_name = name.buf;
> -	cb.value = NULL;
> -	if (git_config(read_branch_desc_cb, &cb) < 0) {
> +	if (git_config_get_string(name.buf, &v)) {
>  		strbuf_release(&name);
>  		return -1;
>  	}
> -	if (cb.value)
> -		strbuf_addstr(buf, cb.value);
> +	strbuf_addstr(buf, v);
> +	free((char*)v);

In this cast, I smell an API mistake to insist an extra constness to
the output parameter of git_config_get_string() in [3/4] of the
previous series.  Unlike the underlying git_config_get_value(),
which lets the caller peek into the internal cached copy, the caller
of git_config_get_string() is given its own copy, and I do not
offhand see a good reason to forbid the caller from modifying it.

>  	strbuf_release(&name);
>  	return 0;
>  }