How to work with an "artificial root commit" in a git repository?

Question

Problem and Motivation

We have a larger git repository on our central server. There is a lot of history in it that we want to keep, so rebasing or squashing anything there is not really an option. However, when cloning the repository to our development servers, only recent history is actually relevant. For us, "recent" can be defined as a given tag and any commit earlier in the history can be omitted. The aim here is to save bandwidth, time and disk space.

Ideas for Approach

The current idea is to clone that tag only, using git clone --branch my-root-tag --depth 1 , treating it as an artificial root commit in that local repository. Afterwards, adding branches that we'd like to fetch manually using git remote set-branches --add origin some-branch . All of these branches must include my-root-tag somewhere in their history. However, every fetch would now again transfer the entire history. Is there any way to restrict fetches to stop at my-root-tag instead? It sounds like this approach would need something like asked in git shallow clone since specific commit , ideally wrapped in a git alias to "dynamically" calculate the value of the --depth parameter.

Can anyone think of a way to get this to work or even by applying some entirely different approach?

Results

edit: To summarize, it seems that a git fetch does indeed only transfer the commits up to the grafted new repository root (at least in Git v 2.25.1). Only the original clone needs to be parameterized correctly, while subsequent operations on the repository can be performed using regular (unparameterized) git commands. No shallow-include or shallow-exclude options are actually necessary now. This is great news as it makes that configuration a lot less fragile than initially feared.

Answer 1

It seems that fetching everything up to a commit is what should happen using --shallow-exclude=my-root-tag See How to maintain shallow clone of a set of branches in git

This similar question suggests using --shallow-since=<date of tagged commit> : Git: Shallow copies from a specific commit

Also related:

• A way to keep a shallow git clone just minimally up to date?
• How to git fetch efficiently from a shallow clone