Subject: Re: [PATCH v2 3/7] config: convert multi_replace to flags

From: Emily Shaffer <[email-masked]>
Date: Mon, 23 Nov 2020 13:43:22 -0800

On Mon, Nov 23, 2020 at 04:05:03PM +0000, Derrick Stolee via GitGitGadget wrote:
> 
> 
> We will extend the flexibility of the config API. Before doing so, let's
> take an existing 'int multi_replace' parameter and replace it with a new
> 'unsigned flags' parameter that can take multiple options as a bit field.
> 
> Update all callers that specified multi_replace to now specify the
> CONFIG_FLAGS_MULTI_REPLACE flag. To add more clarity, extend the
> documentation of git_config_set_multivar_in_file() including a clear
> labeling of its arguments. Other config API methods in config.h require
> only a change of the final parameter from 'int' to 'unsigned'.
> 
> Signed-off-by: Derrick Stolee <[email-masked]>
> ---
> diff --git a/builtin/branch.c b/builtin/branch.c
> index e82301fb1b..5ce3844d22 100644
> --- a/builtin/branch.c
> +++ b/builtin/branch.c
> @@ -829,10 +829,10 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
>  			die(_("Branch '%s' has no upstream information"), branch->name);
>  
>  		strbuf_addf(&buf, "branch.%s.remote", branch->name);
> -		git_config_set_multivar(buf.buf, NULL, NULL, 1);
> +		git_config_set_multivar(buf.buf, NULL, NULL, CONFIG_FLAGS_MULTI_REPLACE);
>  		strbuf_reset(&buf);
>  		strbuf_addf(&buf, "branch.%s.merge", branch->name);
> -		git_config_set_multivar(buf.buf, NULL, NULL, 1);
> +		git_config_set_multivar(buf.buf, NULL, NULL, CONFIG_FLAGS_MULTI_REPLACE);

Converting callers. Straightforward.

[snipping more similar work]

> diff --git a/config.c b/config.c
> index 2b79fe76ad..096f2eae0d 100644
> --- a/config.c
> +++ b/config.c
> @@ -2716,9 +2716,9 @@ void git_config_set(const char *key, const char *value)
>   * if value_regex!=NULL, disregard key/value pairs where value does not match.
>   * if value_regex==CONFIG_REGEX_NONE, do not match any existing values
>   *     (only add a new one)
> - * if multi_replace==0, nothing, or only one matching key/value is replaced,
> - *     else all matching key/values (regardless how many) are removed,
> - *     before the new pair is written.
> + * if (flags & CONFIG_FLAGS_MULTI_REPLACE) == 0, at most one matching
> + *     key/value is replaced, else all matching key/values (regardless
> + *     how many) are removed, before the new pair is written.

This documentation to me sounds like the question you asked on-list the
other day: "does replace-all turn many configs into one, or many configs
into many with the same value?" Is it reflected in user-facing
documentation? Looks like no - you might have a good opportunity here to
make that more clear.

>   *
>   * Returns 0 on success.
>   *
> @@ -2739,7 +2739,7 @@ void git_config_set(const char *key, const char *value)
>  int git_config_set_multivar_in_file_gently(const char *config_filename,
>  					   const char *key, const char *value,
>  					   const char *value_regex,
> -					   int multi_replace)
> +					   unsigned flags)

Well, I wanted to complain about using 'unsigned' instead of 'unsigned
int', but 'git grep -P "unsigned(?! int)"' tells me that it's not a
thing anybody else seems to mind. So I'll just grumble in my corner
instead :)

>  {
>  	int fd = -1, in_fd = -1;
>  	int ret;
> @@ -2756,7 +2756,7 @@ int git_config_set_multivar_in_file_gently(const char *config_filename,
>  	if (ret)
>  		goto out_free;
>  
> -	store.multi_replace = multi_replace;
> +	store.multi_replace = (flags & CONFIG_FLAGS_MULTI_REPLACE) != 0;
>  
>  	if (!config_filename)
>  		config_filename = filename_buf = git_pathdup("config");
> @@ -2845,7 +2845,7 @@ int git_config_set_multivar_in_file_gently(const char *config_filename,
>  
>  		/* if nothing to unset, or too many matches, error out */
>  		if ((store.seen_nr == 0 && value == NULL) ||
> -		    (store.seen_nr > 1 && multi_replace == 0)) {
> +		    (store.seen_nr > 1 && !store.multi_replace)) {

Huh, I wonder why 'store.multi_replace' wasn't used here before, since
it was bothered to be set at earlier. Ah well.

>  void git_config_set_multivar_in_file(const char *config_filename,
>  				     const char *key, const char *value,
> -				     const char *value_regex, int multi_replace)
> +				     const char *value_regex, unsigned flags)

And some more signature conversions. [snip]

>  /**
>   * takes four parameters:
> @@ -276,13 +289,15 @@ int git_config_set_multivar_in_file_gently(const char *, const char *, const cha
>   * - the value regex, as a string. It will disregard key/value pairs where value
>   *   does not match.
>   *
> - * - a multi_replace value, as an int. If value is equal to zero, nothing or only
> - *   one matching key/value is replaced, else all matching key/values (regardless
> - *   how many) are removed, before the new pair is written.
> + * - a flags value with bits corresponding to the CONFIG_FLAG_* macros.
>   *
>   * It returns 0 on success.
>   */
> -void git_config_set_multivar_in_file(const char *, const char *, const char *, const char *, int);
> +void git_config_set_multivar_in_file(const char *config_filename,
> +				     const char *key,
> +				     const char *value,
> +				     const char *value_regex,
> +				     unsigned flags);

Nice opportunity to make the header a little easier to read here.
Thanks.

With just one optional comment,

Reviewed-by: Emily Shaffer <[email-masked]>