feat(gs/emacs): Update hie invocation for depot

Update the invocation of the hie.sh script as part of
+grfn/haskell-mode-setup to be compatible with the new depot-integrated
xanthous.

Change-Id: Ia3ef50fb08464a533efdfed4da66e2be00446ea6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/891
Tested-by: BuildkiteCI
Reviewed-by: glittershark <grfn@gws.fyi>
Reviewed-by: BuildkiteCI

users/glittershark/emacs.d/config.el

@@ -702,16 +702,18 @@
   (flymake-mode -1)
   ;; If there’s a 'hie.sh' defined locally by a project
   ;; (e.g. to run HIE in a nix-shell), use it…
-  (let ((hie-directory (locate-dominating-file default-directory "hie.sh")))
-    (when hie-directory
-      (setq-local lsp-haskell-process-path-hie (expand-file-name "hie.sh" hie-directory))
-      (setq-local
-       haskell-hoogle-command
+  (when-let ((project-dir (locate-dominating-file default-directory "hie.sh")))
+    (cl-flet
+        ((which (cmd)
                 (s-trim
                  (shell-command-to-string
                   (concat
-          "nix-shell " (expand-file-name "shell.nix" hie-directory)
-          " --run \"which hoogle\" 2>/dev/null"))))))
+                   "nix-shell "
+                   (expand-file-name "shell.nix" project-dir)
+                   " --run \"which " cmd "\" 2>/dev/null")))))
+      (setq-local
+       lsp-haskell-process-path-hie (expand-file-name "hie.sh" project-dir)
+       haskell-hoogle-command (which "hoogle"))))
   ;; … and only then setup the LSP.
   (lsp))
 
@@ -727,7 +729,8 @@
   ;; (haskell-mode . lsp-haskell-enable)
   :config
   (add-hook 'haskell-mode-hook #'+grfn/haskell-mode-setup 't)
-  (setq lsp-haskell-process-path-hie "/home/griffin/.nix-profile/bin/hie-8.6.5"
+  (setq
+   ;; lsp-haskell-process-path-hie "/home/griffin/.nix-profile/bin/hie-8.6.5"
    lsp-haskell-process-args-hie
    '("-d" "-l" "/tmp/hie.log" "+RTS" "-M4G" "-H1G" "-K4G" "-A16M" "-RTS")))