lang/rust: add eglot docs & inhibit package.el usage #2195

modules/lang/rust/README.org

@@ -13,6 +13,7 @@
   - [[#keybinds][Keybinds]]
 - [[#configuration][Configuration]]
   - [[#enable-rust-analyzer][Enable rust-analyzer]]
+  - [[#enabling-elgot-support-for-rust][Enabling elgot support for Rust]]
 - [[#troubleshooting][Troubleshooting]]
 
 * Description
@@ -73,11 +74,22 @@ and the ~+lsp~ flag on this module.
 
 * TODO Configuration
 ** Enable rust-analyzer
-You'll need [[https://github.com/rust-analyzer/rust-analyzer][rust-analyzer]] installed on your system, then add the following to
-=$DOOMDIR/config.el=:
+You'll need [[https://github.com/rust-analyzer/rust-analyzer][rust-analyzer]] installed on your system, then use the following:
 
 #+BEGIN_SRC elisp
+;; in $DOOMDIR/config.el
 (setq lsp-rust-server 'rust-analyzer)
 #+END_SRC
 
+** Enabling elgot support for Rust
+Doom doesn't have eglot support (yet), but if you've installed it yourself and
+want rust to use eglot instead of LSP, use the following:
+
+#+BEGIN_SRC elisp
+;; in $DOOMDIR/config.el
+(after! rustic
+  (setq rustic-lsp-server 'rust-analyzer ; optional
+        rustic-lsp-client 'eglot))
+#+END_SRC
+
 * TODO Troubleshooting

modules/lang/rust/config.el

@@ -46,7 +46,23 @@
           :desc "cargo run"      "r" #'rustic-cargo-run)
         (:prefix ("t" . "cargo test")
           :desc "all"          "a" #'rustic-cargo-test
-          :desc "current test" "t" #'rustic-cargo-current-test)))
+          :desc "current test" "t" #'rustic-cargo-current-test))
+
+  (defadvice! +rust--dont-install-packages-p (orig-fn &rest args)
+    :around #'rustic-setup-lsp
+    (cl-letf (;; `rustic-setup-lsp' uses `package-installed-p' to determine if
+              ;; lsp-mode/elgot are available. This breaks because Doom doesn't
+              ;; use package.el to begin with (and lazy loads it).
+              ((symbol-function #'package-installed-p)
+               (lambda (pkg)
+                 (require pkg nil t)))
+              ;; If lsp/elgot isn't available, it attempts to install lsp-mode
+              ;; via package.el. Doom manages its own dependencies so we disable
+              ;; that behavior.
+              ((symbol-function #'rustic-install-lsp-client-p)
+               (lambda (&rest _)
+                 (message "No RLS server running"))))
+      (apply orig-fn args))))
 
 
 (use-package! racer