Subject: Re: [PATCH v2 1/5] mailmap: add a function to inspect the number of entries

From: Ævar Arnfjörð Bjarmason <[email-masked]>
Date: Mon, 04 Jan 2021 16:14:20 +0100

On Sun, Jan 03 2021, brian m. carlson wrote:

> We're soon going to change the type of our mailmap into an opaque struct
> so we can add features and improve performance.  When we do so, it won't
> be possible for users to inspect its internals to determine how many
> items are present, so let's introduce a function that lets users inquire
> how many objects are in the mailmap and use it where we want this
> information.
>
> Signed-off-by: brian m. carlson <[email-masked]>
> ---
>  mailmap.c | 5 +++++
>  mailmap.h | 1 +
>  pretty.c  | 2 +-
>  3 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/mailmap.c b/mailmap.c
> index 962fd86d6d..c9a538f4e2 100644
> --- a/mailmap.c
> +++ b/mailmap.c
> @@ -361,3 +361,8 @@ int map_user(struct string_list *map,
>  	debug_mm("map_user:  --\n");
>  	return 0;
>  }
> +
> +int mailmap_entries(struct string_list *map)

We're returning ->nr here from string_list, whose "nr" is unsigned
int. Wouldn't it make more sense to do the same here?...

> +{
> +	return map->nr;
> +}
> diff --git a/mailmap.h b/mailmap.h
> index d0e65646cb..ff57b05a15 100644
> --- a/mailmap.h
> +++ b/mailmap.h
> @@ -5,6 +5,7 @@ struct string_list;
>  
>  int read_mailmap(struct string_list *map, char **repo_abbrev);
>  void clear_mailmap(struct string_list *map);
> +int mailmap_entries(struct string_list *map);
>  
>  int map_user(struct string_list *map,
>  			 const char **email, size_t *emaillen, const char **name, size_t *namelen);
> diff --git a/pretty.c b/pretty.c
> index 7a7708a0ea..43a0039870 100644
> --- a/pretty.c
> +++ b/pretty.c
> @@ -681,7 +681,7 @@ static int mailmap_name(const char **email, size_t *email_len,
>  		mail_map = xcalloc(1, sizeof(*mail_map));
>  		read_mailmap(mail_map, NULL);
>  	}
> -	return mail_map->nr && map_user(mail_map, email, email_len, name, name_len);
> +	return mailmap_entries(mail_map) && map_user(mail_map, email, email_len, name, name_len);

...and isn't this introducing a bug where the number of entries is
beyond "signed int" but not "unsigned int" by overflowing?

Bikeshedding: For both hashmap and strmap we have a
{hashmap,strmap}_get_size() function. I think a "static inline unsigned
int mailmap_get_size()" here would be more consistent & obvious.

>  }
>  
>  static size_t format_person_part(struct strbuf *sb, char part,