Re: [RFC] Submodules in GIT

From: Linus Torvalds <torvalds@osdl.org>
Date: Dec 3, 2006, 17:54 UTC
Message-ID: <Pine.LNX.4.64.0612030946150.3476@woody.osdl.org>
In-Reply-To: <e7bda7770612030119v197cbc95h6b3fa9e22b78c058@mail.gmail.com>

On Sun, 3 Dec 2006, Torgil Svensson wrote:

Show 8 quoted lines

>
> On 12/2/06, Linus Torvalds <torvalds@osdl.org> wrote:
> > 
> > In other words, I don't think people expect or want something hugely more
> > complicated than the CVS/modules kind of file.
> 
> What about the case when you want _everything_, do you then have to
> know the names of all submodules, present and past?

Afaik, the way people do this historically is simply:

 - often have an alias for "everything" (eg "all" or "src" or "world"), 
   and if you want everything, you basically ask for it by checking out 
   the "src" module.

   Ie this is the "upstream" way to let downstream check out everything.

 - if you're downstream, and you have a partial repo, and you realize that 
   you want everything else, you just look at gitweb (assuming it is 
   extended to show module information, of course ;) or the .gitmodules 
   (or whatever it would be called) file to get the other pieces manually.

But hey, I also think it would be fine to have "git clone --allmodules" or something ("fetch" too). I think this whole question will depend more on how people end up _using_ module support than on any technical issues per se. Again, I suspect the people who now set up modules in CVS are likely to have a better idea than I do about how they usually do it (and why).

> If you have an old irrelevant submodule in the history that happens to
> have the same name as one of them you are interested in, do you get
> this as well?

I dunno. Details, details. I'm also not sure this is hugely important.

It could be "solved" by simply having the requirement that all modules need to be named differently (notice that "module name" is _not_ the same thing as "the directory name where the module shows up". That's not the case even in CVS modules, and with a "link" type in the git tree object, the directory where a module shows up would basically be totally independent of the "name" of the module).

> During a debugging session it might be convenient to do a "all but X"
> kind of fetch if you have a project dependent on several small modules
> and one of them is the big black sheep.

I suspect it's more common to name the modules you want to fetch explicitly, rather than make it a "negative" choice, but that sounds largely like just an interface issue.