bug#41821: 28.0.50; read-directory-name in vc commands should provide defaults from projects

[Eli Zaretskii]

> Cc: 41821@debbugs.gnu.org, juri@linkov.net
> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Thu, 25 Jun 2020 20:19:27 +0300
> 
> > We are going in circles again.  Can you explain why vc-known-roots
> > cannot be moved to vc.el in its entirety?
> 
> To re-iterate:
> 
> - We can't just move it: it accesses information private to project.el.

What does project.el has to do with this?  I didn't ask to move the
function to project.el.  What am I missing?

> - We can't move said information (the variable and mechanism to 
> save/restore it)

Which information? what variable?  Please be more specific.