bug#73279: [PATCH] Eglot: use immediate-mode eglot--request for :completionItem/resolve

[Eli Zaretskii <eliz@gnu.org>]

> From: Brennan Vincent <brennan@umanwizard.com>
> Date: Sun, 15 Sep 2024 15:22:05 -0400
> 
> * lisp/progmodes/eglot.el: use immediate-mode eglot--request for
> :completionItem/resolve in eglot-completion-at-point.
> 
> With the previous behavior, we are informing the language server of the
> modified state of the buffer after initially inserting the completion,
> but before fully resolving the completion item.
> 
> This confuses rust-analyzer (and maybe others, I don't know) and causes
> it not to return the correct set of additionalTextEdits.
> 
> A simple Rust program that reveals the issue follows. Put the point
> after HashSet and attempt to complete. With the previous behavior, the
> language server fails to tell us to insert "use
> std::collections::HashSet" at the top of the file. With the new behavior
> as of this commit, completion works successfully (as it did in emacs
> 29.4).
> 
> struct S<T> {
>     x: T
> }
> 
> impl<T> S<HashSet<T>> {
> }
> 
> fn main() {}
> ---
>  lisp/progmodes/eglot.el | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/lisp/progmodes/eglot.el b/lisp/progmodes/eglot.el
> index 82e99a2c920..e9de099d2cd 100644
> --- a/lisp/progmodes/eglot.el
> +++ b/lisp/progmodes/eglot.el
> @@ -3229,7 +3229,9 @@ eglot-completion-at-point
>                                                          :resolveProvider)
>                                   (plist-get lsp-comp :data))
>                              (eglot--request server :completionItem/resolve
> -                                            lsp-comp :cancel-on-input t)
> +                                            lsp-comp
> +                                            :cancel-on-input t
> +                                            :immediate t)
>                            lsp-comp))))))
>        (when (and (consp eglot--capf-session)
>                   (= (car bounds) (car (nth 0 eglot--capf-session)))
> -- 
> 2.45.2

João, any comments?