bug#63648: 29.0.90; project.el: with switch-use-entire-map, switch-project errors on non-project commands

[Dmitry Gutov]

On 01/06/2023 19:05, Juri Linkov wrote:
> > > 1. the current buffer should remain the same for the next command;
> > > 2. the buffer-local value of 'default-directory' should remain the same;
> > > 3. the next command should have a new value of 'default-directory'.
> > >
> > > I see no way to satisfy all these requirements.
> >
> > Except adding a variable like 'project-current-directory-override'
> > somewhere inside 'command_loop_1'.
>
> And indeed with the following patch replacing the current definition of
> 'project-switch-project' with just:
>
>    (defun project-switch-project (dir)
>      (interactive (list (funcall project-prompter)))
>      (setq next-default-directory dir))

Note that we'd need to keep the previous implementation for a number of 
years anyway, to retain compatibility with older emacsen.

> 'C-x p p (select project ...) RET M-& pwd RET' confirms that
> the command runs in the selected project directory.
> Whereas the original buffer keeps its previous buffer-local value
> of 'default-directory'.

I suggest you bring up this feature addition on emacs-devel, or 
otherwise wait for a review from Eli, at least.

It's not a big addition, but it's a distinct new feature (the 
next-default-directory var).