How to shallow clone a local git repository with a relative path?

Question

Shallow clones of local directories require file:// as explained at: git clone: warning: --depth is ignored in local clones; use file:// instead

But how

Answer 1

But how to use relative paths with that?

This is not supported; file:// expects only absolute paths. There are e.g. RFC1738 and RFC8089 which describe this kind of URIs.

A file URL takes the form:

   file:///

where is the fully qualified domain name of the system on
which the is accessible, and is a hierarchical
directory path of the form //.../.

When you write file://mymodule, the mymodule can be interpreted as a hostname.