Subject: Re: [PATCH] apply: replace mksnpath() with a mkpathdup() call

From: Junio C Hamano <[email-masked]>
Date: Thu, 04 Apr 2024 14:29:42 -0700

René Scharfe <[email-masked]> writes:

> Support paths longer than PATH_MAX in create_one_file() (which is not a
> hard limit e.g. on Linux) by calling mkpathdup() instead of mksnpath().
> Remove the latter, as it becomes unused by this change.  Resist the
> temptation of using the more convenient mkpath() to avoid introducing a
> dependency on a static variable deep inside the apply machinery.
>
> Suggested-by: Jeff King <[email-masked]>
> Signed-off-by: René Scharfe <[email-masked]>
> ---
>  apply.c | 13 +++++++++----
>  path.c  | 17 -----------------
>  path.h  |  6 ------
>  3 files changed, 9 insertions(+), 27 deletions(-)

As a patch to "apply", this is perfectly good, but in the larger
picture, the value of the patch is in getting rid of mksnpath, isn't
it?

I am tempted to

 - queue it on rs/retire-mksnpath topic branch

 - remove the mention of mksnpath in contrib/vscode/init.sh (I think
   it is registering non-words to spell checker, so having an extra
   entry there would not hurt, but it would more likely to be a typo
   of mkpath than before this patch retires mksnpath function).

 - ask you to come up with a title with more focus on mksnpath than
   on apply.

Thanks.

> diff --git a/apply.c b/apply.c
> index 432837a674..4793b05f3d 100644
> --- a/apply.c
> +++ b/apply.c
> @@ -4502,17 +4502,22 @@ static int create_one_file(struct apply_state *state,
>  		unsigned int nr = getpid();
>
>  		for (;;) {
> -			char newpath[PATH_MAX];
> -			mksnpath(newpath, sizeof(newpath), "%s~%u", path, nr);
> +			char *newpath = mkpathdup("%s~%u", path, nr);
>  			res = try_create_file(state, newpath, mode, buf, size);
> -			if (res < 0)
> +			if (res < 0) {
> +				free(newpath);
>  				return -1;
> +			}
>  			if (!res) {
> -				if (!rename(newpath, path))
> +				if (!rename(newpath, path)) {
> +					free(newpath);
>  					return 0;
> +				}
>  				unlink_or_warn(newpath);
> +				free(newpath);
>  				break;
>  			}
> +			free(newpath);
>  			if (errno != EEXIST)
>  				break;
>  			++nr;
> diff --git a/path.c b/path.c
> index 8bb223c92c..67229edb9c 100644
> --- a/path.c
> +++ b/path.c
> @@ -28,8 +28,6 @@ static int get_st_mode_bits(const char *path, int *mode)
>  	return 0;
>  }
>
> -static char bad_path[] = "/bad-path/";
> -
>  static struct strbuf *get_pathname(void)
>  {
>  	static struct strbuf pathname_array[4] = {
> @@ -59,21 +57,6 @@ static void strbuf_cleanup_path(struct strbuf *sb)
>  		strbuf_remove(sb, 0, path - sb->buf);
>  }
>
> -char *mksnpath(char *buf, size_t n, const char *fmt, ...)
> -{
> -	va_list args;
> -	unsigned len;
> -
> -	va_start(args, fmt);
> -	len = vsnprintf(buf, n, fmt, args);
> -	va_end(args);
> -	if (len >= n) {
> -		strlcpy(buf, bad_path, n);
> -		return buf;
> -	}
> -	return (char *)cleanup_path(buf);
> -}
> -
>  static int dir_prefix(const char *buf, const char *dir)
>  {
>  	int len = strlen(dir);
> diff --git a/path.h b/path.h
> index e053effef2..ea96487b29 100644
> --- a/path.h
> +++ b/path.h
> @@ -23,12 +23,6 @@ const char *mkpath(const char *fmt, ...)
>  char *mkpathdup(const char *fmt, ...)
>  	__attribute__((format (printf, 1, 2)));
>
> -/*
> - * Construct a path and place the result in the provided buffer `buf`.
> - */
> -char *mksnpath(char *buf, size_t n, const char *fmt, ...)
> -	__attribute__((format (printf, 3, 4)));
> -
>  /*
>   * The `git_common_path` family of functions will construct a path into a
>   * repository's common git directory, which is shared by all worktrees.
> --
> 2.44.0