bug#41890: 28.0.50; [PATCH]: Add bindings for project.el

[Juri Linkov]

>> But why project--keymap-prompt, though? I thought you were going to do
>> something that would look like a "normal" prefix keymap. They don't prompt.
>
> Over in the other bug I received feedback from Juri which I understood
> as saying that only a patch using the prompting approach would be likely
> to be merged, so I've been working on that.  Sounds like things are more
> undecided than I thought?

Sorry for the confusion.  Actually I referred to the patch that sets
the transient map.  The fact that it also displays a prompt is a minor detail,
not needed for your patch.

The patch that I referred to was posted by Philip in
https://debbugs.gnu.org/41890#50  This patch uses
set-transient-map to set project-prefix-map,
and the prompt is displayed by ‘message’.

But later Philip sent another patch in
https://debbugs.gnu.org/41890#100
that doesn't use set-transient-map
for the reasons that I don't understand.
Providing the explanation Philip said:

  It turned out that the transient map approach didn't work, as it
  ignored the value in default-directory, thus running all commands in
  whatever the current project was.

Maybe the same function can set default-directory
to solve the problem to be able to use set-transient-map?