bug#59214: [PATCH] Alternate rust-analyzer command added

[M. Ian Graham]

Pankaj Jangid <pankaj@codeisgreat.org> wrote:

> -(defvar eglot-server-programs `((rust-mode . ,(eglot-alternatives 
> '("rust-analyzer" "rls")))
> +(defvar eglot-server-programs `((rust-mode . ,(eglot-alternatives 
> '("rust-analyzer" "("rustup" "run" "stable" "rust-analyzer") "rls")))

I just noticed this quote from the announcement at 
https://blog.rust-lang.org/2022/09/22/Rust-1.64.0.html#rust-analyzer-is-now-available-via-rustup
 :

> At this time, to run the rustup-installed version, you need to invoke it this 
> way:
> rustup run stable rust-analyzer
> The next release of rustup will provide a built-in proxy so that running the 
> executable rust-analyzer will launch the appropriate version.

So the current situation is temporary. A rustup-side fix is coming. Once it 
arrives, the right answer--even for rustup users--will be "just add what you 
want to PATH and eglot will defer to your environment." Rustup will do this for 
them automatically, for the rust version of their preference, and eglot will 
just work.

In the meantime, as is, rustup users have the option of symlinking 
rust-analyzer into .cargo/bin or adding its location directly to PATH. Anyone 
not comfortable doing this is also probably not running emacs from master, so 
they're unlikely to benefit from a short-term elisp fix until the problem goes 
away. And if emacs adds code depending on rustup, subsequently removing what 
should theoretically be a temporary fix will in practice break users remaining 
on older rustup versions.

Unless I'm misunderstanding the situation above or something has changed since 
the announcement, to me it seems prudent to wait on rustup's fix and avoid 
letting emacs develop an opinion about the installation method or version 
details of external components.

Cheers,
Ian