Add `lsp-use-workspace-root-for-server-default-directory' (#3327)

This is a buffer-local variable to enable temporarily binding
`default-directory' to `lsp-workspace-root' when running an LSP server, allowing
for project-local LSP server installations (e.g. as with `dotnet tool` for F#).

Author: drvink

CHANGELOG.org

@@ -36,6 +36,7 @@
   * Drop deprecated rust-analyzer variable lsp-rust-analyzer-import-merge-behaviour
   * Added run and debug code lenses to ~lsp-kotlin~
   * Add setting UPDATE_EXPECT=1 when running `expect!` tests ~lsp-rust~
+  * Add ~lsp-use-workspace-root-for-server-default-directory~.
 ** Release 8.0.0
   * Add ~lsp-clients-angular-node-get-prefix-command~ to get the Angular server from another location which is still has ~/lib/node_modules~ in it.
   * Set ~lsp-clients-angular-language-server-command~ after the first connection to speed up subsequent connections.

clients/lsp-fsharp.el

@@ -167,6 +167,20 @@ UPDATE? is t."
    error-callback
    "dotnet" "tool" (if update? "update" "install") "-g" "fsautocomplete"))
 
+(defcustom lsp-fsharp-use-dotnet-tool-for-fsac t
+  "Run FsAutoComplete as a dotnet tool.
+
+The binary will be invoked via \"dotnet fsautocomplete\" in the
+project's root directory, which will run a project-local tool if
+available, else the globally installed tool."
+  :group 'lsp-fsharp
+  :type 'boolean
+  :risky t)
+
+(defun lsp-fsharp--fsac-cmd ()
+  "The location of fsautocomplete executable."
+  (expand-file-name "fsautocomplete.dll" lsp-fsharp-server-install-dir))
+
 (defun lsp-fsharp--make-launch-cmd ()
   "Build the command required to launch fsautocomplete."
 
@@ -199,8 +213,10 @@ UPDATE? is t."
 
 (defun lsp-fsharp--test-fsautocomplete-present ()
   "Return non-nil if dotnet tool fsautocomplete is installed globally."
-  (string-match-p "fsautocomplete"
-                  (shell-command-to-string "dotnet tool list -g")))
+  (if lsp-fsharp-use-dotnet-tool-for-fsac
+      (string-match-p "fsautocomplete"
+                      (shell-command-to-string "dotnet tool list -g"))
+    (f-exists? (lsp-fsharp--fsac-cmd))))
 
 (defun lsp-fsharp--project-list ()
   "Get the list of files we need to send to fsharp/workspaceLoad."

lsp-mode.el

@@ -200,6 +200,9 @@ Takes a value accepted by `spinner-start'."
                  ,@(mapcar (lambda (c) (list 'const (car c)))
                            spinner-types)))
 
+(defvar-local lsp-use-workspace-root-for-server-default-directory nil
+  "Use `lsp-workspace-root' for `default-directory' when starting LSP process.")
+
 (defvar-local lsp--cur-workspace nil)
 
 (defvar-local lsp--cur-version 0)
@@ -7021,6 +7024,16 @@ Ignore non-boolean keys whose value is nil."
                                                       (eval value))))
                     process-environment))))
 
+(defun lsp--default-directory-for-connection (&optional path)
+  "Return path to be used for the working directory of a LSP process.
+
+If `lsp-use-workspace-root-for-server-default-directory' is
+non-nil, uses `lsp-workspace-root' to find the directory
+corresponding to PATH, else returns `default-directory'."
+  (if lsp-use-workspace-root-for-server-default-directory
+      (lsp-workspace-root path)
+    default-directory))
+
 (defun lsp-stdio-connection (command &optional test-command)
   "Returns a connection property list using COMMAND.
 COMMAND can be: A string, denoting the command to launch the
@@ -7045,6 +7058,7 @@ returned by COMMAND is available via `executable-find'"
                          (process-environment
                           (lsp--compute-process-environment environment-fn)))
                      (let* ((stderr-buf (format "*%s::stderr*" process-name))
+                            (default-directory (lsp--default-directory-for-connection))
                             (proc (make-process
                                    :name process-name
                                    :connection-type 'pipe