Re: [PATCH v5 04/11] setup_git_directory_1(): avoid changing global state

>  /*
>   * We cannot decide in this function whether we are in the work tree or
>   * not, since the config can only be read _after_ this function was called.
> + *
> + * Also, we avoid changing any global state (such as the current working
> + * directory) to allow early callers.
> + *
> + * The directory where the search should start needs to be passed in via the
> + * `dir` parameter; upon return, the `dir` buffer will contain the path of
> + * the directory where the search ended, and `gitdir` will contain the path of
> + * the discovered .git/ directory, if any. This path may be relative against
> + * `dir` (i.e. *not* necessarily the cwd).

> -static const char *setup_git_directory_gently_1(int *nongit_ok)
> +static enum discovery_result setup_git_directory_gently_1(struct strbuf *dir,
> ...
> @@ -889,63 +888,104 @@ static const char *setup_git_directory_gently_1(int *nongit_ok)
>  	 */
>  	one_filesystem = !git_env_bool("GIT_DISCOVERY_ACROSS_FILESYSTEM", 0);
>  	if (one_filesystem)
> -		current_device = get_device_or_die(".", NULL, 0);
> +		current_device = get_device_or_die(dir->buf, NULL, 0);
>  	for (;;) {
> -		gitfile = (char*)read_gitfile(DEFAULT_GIT_DIR_ENVIRONMENT);
> -		if (gitfile)
> -			gitdirenv = gitfile = xstrdup(gitfile);
> -		else {
> -			if (is_git_directory(DEFAULT_GIT_DIR_ENVIRONMENT))
> -				gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
> +		int offset = dir->len;
> +
> +		if (offset > min_offset)
> +			strbuf_addch(dir, '/');
> +		strbuf_addstr(dir, DEFAULT_GIT_DIR_ENVIRONMENT);
> +		gitdirenv = read_gitfile(dir->buf);
> +		if (!gitdirenv && is_git_directory(dir->buf))
> +			gitdirenv = DEFAULT_GIT_DIR_ENVIRONMENT;
> +		strbuf_setlen(dir, offset);
> +		if (gitdirenv) {
> +			strbuf_addstr(gitdir, gitdirenv);
> +			return GIT_DIR_DISCOVERED;
>  		}