Re: [PATCH v6 1/6] submodules: add helper functions to determine presence of submodules

From: Brandon Williams <bmwill@google.com>
Date: Dec 2, 2016, 21:46 UTC
Message-ID: <20161202214603.GD117792@google.com>
In-Reply-To: <CA+P7+xpJ1=TiWq60wO4ftA-Y6SHAkdbLk=srbTQQsB=D1ZGkrw@mail.gmail.com>

On 12/02, Jacob Keller wrote:

Show 22 quoted lines

> On Fri, Dec 2, 2016 at 11:28 AM, Stefan Beller <sbeller@google.com> wrote:
> > On Fri, Dec 2, 2016 at 11:20 AM, Jacob Keller <jacob.keller@gmail.com> wrote:
> >>>
> >>> So is there a reason why the library function realpath() can't be used?
> >>> From a cursory look at its man page it seems to do the symlink
> >>> resolution.
> >>>
> >>> --
> >>> Brandon Williams
> >>
> >> I believe it uses the same method and thus wouldn't actually resolve
> >> the issue. But I'm not really 100% sure on this.
> >>
> >> Thanks,
> >> Jake
> >
> > I just reviewed 2 libc implementations (glibc and an Android libc) and
> > both of them
> > do not use chdir internally, but use readlink and compose the path 'manually'
> > c.f. http://osxr.org:8080/glibc/source/stdlib/canonicalize.c?v=glibc-2.13
> 
> Interesting. Would this be portable to Windows, though?

Perhaps. It looks like the only crazy thing it does is use readlink, which our real_path function is already doing. I don't think we could drop in their implementation though since there are other things that it does that aren't portable to windows (like determining if a path is absolute or not). Rather their implementation gives me some hope that it is possible to resolve the real path without using chdir.

-- 
Brandon Williams