Re: [PATCH 4/4] submodule--helper: use relative path if possible

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 31, 2016, 16:59 UTC
Message-ID: <xmqqd1qapore.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <1459383457-6848-5-git-send-email-sbeller@google.com>

Stefan Beller <sbeller@google.com> writes:

Show 36 quoted lines

> As submodules have working directory and their git directory far apart
> relative_path(gitdir, work_dir) will not produce a relative path when
> git_dir is absolute. When the gitdir is absolute, we need to convert
> the workdir to an absolute path as well to compute the relative path.
>
> (e.g. gitdir=/home/user/project/.git/modules/submodule,
> workdir=submodule/, relative_dir doesn't take the current working directory
> into account, so there is no way for it to know that the correct answer
> is indeed "../.git/modules/submodule", if the workdir was given as
> /home/user/project/submodule, the answer is obvious.)
>
> Signed-off-by: Stefan Beller <sbeller@google.com>
> ---
>  builtin/submodule--helper.c | 7 +++++++
>  t/t7400-submodule-basic.sh  | 2 +-
>  2 files changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
> index 914e561..0b0fad3 100644
> --- a/builtin/submodule--helper.c
> +++ b/builtin/submodule--helper.c
> @@ -159,6 +159,7 @@ static int module_clone(int argc, const char **argv, const char *prefix)
>  	FILE *submodule_dot_git;
>  	char *sm_gitdir, *cwd, *p;
>  	struct strbuf rel_path = STRBUF_INIT;
> +	struct strbuf abs_path = STRBUF_INIT;
>  	struct strbuf sb = STRBUF_INIT;
>  
>  	struct option module_clone_options[] = {
> @@ -219,7 +220,12 @@ static int module_clone(int argc, const char **argv, const char *prefix)
>  	if (!submodule_dot_git)
>  		die_errno(_("cannot open file '%s'"), sb.buf);
>  
> +	strbuf_addf(&abs_path, "%s/%s",
> +		    get_git_work_tree(),
> +		    path);

The "path" is assumed to be _always_ relative to work tree?

I am wondering if it would be prudent to have an assert for that before doing this, just like I suggested assert(path) for [2/4] earlier [*1*].

On the other hand, if we allow path to be absolute, this would need to become something like:

	if (is_absolute_path(path))
        	strbuf_addstr(&abs_path, path);
	else
        	strbuf_addf(&abs_path, "%s/%s", get_git_work_tree(), path);

>  	fprintf(submodule_dot_git, "gitdir: %s\n",
> +		is_absolute_path(sm_gitdir) ?
> +		relative_path(sm_gitdir, abs_path.buf, &rel_path) :
>  		relative_path(sm_gitdir, path, &rel_path));

It seems that the abs_path computation is not needed at all if sm_gitdir is relative to begin with. I wonder if the code gets easier to read and can avoid unnecessary strbuf manipulation if this entire hunk is structured more like so:

	if (is_absolute_path(sm_gitdir)) {
		...
	} else {
        	...
	}
	fprintf(submodule_dot_git, "gitdir: %s\n",
        	relative_path(sm_gitdir, base_path, &rel_path));

>  	if (fclose(submodule_dot_git))
>  		die(_("could not close file %s"), sb.buf);

[Footnote]

*1* BTW, I tightened the assert for 2/4 to "assert(path && *path)" to match the assumption in its log message, i.e. "The calling shell code makes sure that path is non-NULL and non empty".