bug#70577: [PATCH] New command other-project-prefix

[Juri Linkov <juri@linkov.net>]

>> Something is wrong here.  I bound 'other-project-prefix' to 'C-x p P'.
>> Then typing 'C-x p P C-x d' asked a directory name, then later
>> after selecting a project asked for the directory name again.
>
> Looks like that has to do with the interactive spec. See the attached next
> revision, it seems to behave better.

Thanks, this works now (except that it can't be debugged because of the
Lisp error: (wrong-type-argument listp ignore)).

Also 'C-h' is not a problem: 'help-form-show' does nothing
without 'help-form', but with 'help-form' works fine:

      (define-key map (vector help-char)
                  (lambda ()
                    (interactive)
                    (let ((help-form "You can use any global keybinding."))
                      (help-form-show))))

However, a much bigger problem is that unfortunately many test cases from
https://debbugs.gnu.org/63648#203 are broken.  For example,
'C-x p p C-b' fails the same way as in bug#58784.
'C-x p p f M-n' fails because it expects to read arguments
in a previous project with an old value of default-directory, etc.

Maybe this could be fixed by running 'interactive' in a previous project
by using something like:

  (around-fun
   (lambda (command &rest _args)
     (interactive (lambda (spec)
                    (let ((default-directory prev-dir))
                      (advice-eval-interactive-spec spec))))