Sorry for the possible duplicate, but it seems this message didn't reach 
the bug tracker, or other recipients. Resending contents below.

On 23/08/2023 20:54, Juri Linkov wrote:
> There is no code where to bind a dynamic variable, because its value
> should be available for the next command in the command loop.
> If you agree there is no other way to implement this than next-default-directory,
> then I could bring up the discussion on emacs-devel.

Before we dive into all that, why not try advice on 'command-execute'? 
For the PoC code at least. It's in Lisp since 2013.

The comment in its body does say "Called directly from the C code", but 
I'm not sure if that has any direct implications for us.

This attached piece of code implements the project-switch-project as you 
outlined. Does it work well for you/others? Careful when testing or 
modifying: a typo can break the command loop (and thus the session).

To me it seems a little too bare-bones, lacking the instructive hints 
project-switch-project currently has.