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 19:45:45 +0300
> 
> >>> Anyway, if you-two feel strongly about keeping the current solution,
> >>> i.e. having VC commands use project.el-collected history, I'd
> >>> appreciate if that function could be moved to vc.el from vc-hooks.el,
> >>> thanks in advance.
> >>
> >> We can't just move it: it accesses information private to project.el.
> >> The best we could do is a wrapper function.
> > 
> > Sorry, I don't understand: why can't we move it from vc-hooks.el to
> > vc.el, and why doing that would need a wrapper?
> 
> It would be a wrapper for a project.el function. But if it works for 
> you, okay.

We are going in circles again.  Can you explain why vc-known-roots
cannot be moved to vc.el in its entirety?