Re: How de-duplicate similar repositories with alternates

From: Derrick Stolee <stolee@gmail.com>
Date: Dec 4, 2018, 12:07 UTC
Message-ID: <5f2f5c9f-c27b-2577-ca4d-375c92ab9186@gmail.com>
In-Reply-To: <20181204070602.GB11010@sigill.intra.peff.net>

On 12/4/2018 2:06 AM, Jeff King wrote:

Show 9 quoted lines

> On Thu, Nov 29, 2018 at 10:55:49AM -0800, Stefan Beller wrote:
>
>> I view alternates as a historic artefact as the deduping
>> of objects client side can be done using worktrees, and on the
>> serverside - I think - most of the git hosters use namespaces
>> and put a fork network into the same repository and use pack islands.
> By contrast, object storage is pretty easy to share. It scales
> reasonably well, and the security model is much simpler due to the
> immutable nature of object names.

And for the client side, we use alternates as an important way to scale VFS for Git to multiple enlistments on the same machine. VFS for Git manages a "shared object cache" (the alternate) that is updated in the background (including multi-pack-index and commit-graph).

Using worktrees for the same effect would add complications to the user interactions, not only when creating an enlistment but the fact that two enlistments cannot check out the same ref will confuse users.

Thanks, -Stolee