How to deal with partial svn:externals when migrat

Question

I would like to import a SVN repository into a GitHub Enterprise repository

There are many questions related to this matter and most of them can be addressed either with Git submodules or Git subtree.

In my case I have two repositories:

• The main project repository
• The modules repository (a big SVN repository over 2 GB)

This module repository has the following architecture:

foolib/
   moduleA/
      ...
   moduleB/
      ...
   ...

For the project, only few modules from foolib are used as svn:externals. For example this main project only uses moduleA from foolib.

As mentioned in this question one possible solution is to use sparse-checkout. I'm guessing Git subtree would also do the trick. Unfortunately it doesn't solve the main issue.

If my project is very small, as long as I get something from foolib, even with sparce-checkout, I will retrieve the whole history of foolib (e.g. 2 GB). This issue doesn't exist with SVN because an svn:externals property only fetches what it needs, not the whole history.

I can imagine to do foolish things like recreating a local sparse repository dynamically using the commits listed in git log --follow foolib/moduleA. But I assume this is not a good solution.

What would be the correct workflow to get a similar behavior in Git without having to fetch the whole history of foolib everything I need only few modules?