bug#61868: 29.0.60; Eglot: setting "workspace" configurations should be easier

[Augusto Stoffel <arstoffel@gmail.com>]

On Tue, 28 Feb 2023 at 19:33, João Távora wrote:

> Augusto Stoffel <arstoffel@gmail.com> writes:
>
>> I would suggest adding a refined version of this, using a regular buffer
>> for input.  Moreover, one could allow editing the configuration as a
>> JSON (perhaps also retaining the option to edit as a plist).  This would
>> be a natural extension of the existing
>> `eglot-show-workspace-configuration' command.
>
> I like this idea.  I agree it's crazy hard to set and get right.  But
> this idea needs to be refined indeed.
>
> I'm not crazy about adding this complexity to Eglot, especially because
> there's nothing really eglot-specific about it.  It could be used for
> any variable you want to add to the current project's root
> .dir-locals.el.  But that involves much more consultation in
> emacs-devel.

I see this differently.  Emacs doesn't have deeply nested namespaces for
variables and user options.  It's all pretty flat, so there is almost
surely never going to be a variable that is nearly as tricky to set.

[ Incidentally, when I suggested to allow such syntax:

       ((python-mode
       . ((eglot-workspace-configuration
           . (("pylsp.plugins.jedi_completion.include_params" . t)
              ("pylsp.plugins.jedi_completion.fuzzy" . t)
              ("pylsp.plugins.pylint.enabled" . :json-false))))))

   you said it was un-Lispy or something, but I really think it's rather
   the opposite.  Emacs has flat names pretty much like the above. ]

> Here's an idea.  Let's make a bare-bones
> eglot-show-workspace-configuration that simplifies this 80%.  The other
> 20% can for later.
>
> In the patch I sent for the other "workspace configuration" bug, the
> .dir-locals.el is consulted late (actually it is even now).  So a simple
> implementation of eglot-edit-workspace-configuration could be just:
>
>   (defun eglot-edit-workspace-configuration () (interactive)
>     (find-file (expand-file-name ".dir-locals.el" (project-root (project-current)))))
>
> My bet is that that two-liner would go a long way.

No, this is not enough.  At the very least I need a history variable to
look at the previous configurations.  This feature has to be a thing on
top of of `eglot-show-workspace-configuration'.