Re: Saving space/network on common repos

From: Craig Silverstein <csilvers@khanacademy.org>
Date: Dec 17, 2014, 23:57 UTC
Message-ID: <CAGXKyzEqTik3p=A8NZJ6kUscFjw_Dh1mBPT-ciwq9L8kNKDDig@mail.gmail.com>
In-Reply-To: <20141217223215.GO29365@google.com>

On Wed, Dec 17, 2014 at 2:32 PM, Jonathan Nieder <jrnieder@gmail.com> wrote:

> You might find 'git new-workdir' from contrib/workdir to be helpful.
> It lets you attach multiple working copies to a single set of objects
> and refs.

Thanks! That does indeed sound promising -- like a more principled version of my GIT_OBJECT_DIRECTORY suggestion.

Show 6 quoted lines

>> Question 4) Is there a practical way to set up submodules so they can
>> use the same object-sharing framework that the main repo does?
>
> It's possible to do, but we haven't written a nice UI for it yet.
> (In other words, you can do this by cloning with --no-recurse-submodules
> and manually creating the submodule workdir in the appropriate place.

Hmm, let me see if I understand you right -- you're suggesting that
when cloning my reference repo, I do
    git clone --no-recurse-submodules <my repo>
    for (path, url) in `parse-.gitmodules`: git clone url path
# this is psuedocode, obviously :-)

and then when I want to create a new workdir, I do something like:
    cd reference_repo
    git new-workdir /var/workspace1
    for (path, url) in `parse-.gitmodules`: cd path && git new-workdir
/var/workspace1/path

? Basically, I'm going back to the old git way of having each submodule have its own .git directory, rather than having it have a .git file with a 'gitdir' entry. Am I understanding this right?

Also, it seems to me there's the possibility, with git-newdir, that if several of the workspaces try to fetch at the same time they could step on each others' toes. Is that a problem? I know there's a push lock but I don't believe there's a fetch lock, and I could imagine git getting unhappy if two fetches happened in the same repo at the same time.

craig