Subject: bug#79024: Other working tree information in project--list

From: Sean Whitton <[email-masked]>
Date: Mon, 21 Jul 2025 10:53:29 +0100

Hello,

On Fri 18 Jul 2025 at 10:36am +01, Sean Whitton wrote:

> Dmitry, what do you think about a new project-prompter-predicate which
> project prompters should use to filter the list of projects offered?  VC
> could bind that to something which only lets through related worktrees.

I've got a second extension of project.el to ask about.

Mercurial doesn't maintain records of shared repositories.
The first repository knows nothing about shares created from it, and
each share only has a reference back to the first repository.

Therefore, to support the VC API for other working trees, Emacs needs to
maintain records of its own about other working trees for Mercurial
repositories.

Initially I'll implement this by just looking it up each time but that
will get slow.  project--list's docstring talks about storing metadata
there.  Could I perhaps treat the entries in project--list as plists or
alists, and push some entries there?  I could use symbols with a vc--
prefix as the keys into the lists, indicating this is not data that
project.el itself should have much to do with?  Or what do you think?

-- 
Sean Whitton