feat(config): Allow overriding the root_dir

CHANGELOG.md

@@ -6,6 +6,13 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+
+### Added
+
+- Config: Add a new `config.server.root_dir` option to override the root
+  directory detection logic
+
 ## [4.23.5] - 2024-05-24
 
 ### Fixed

doc/rustaceanvim.txt

@@ -234,12 +234,13 @@ RustcOpts                                                            *RustcOpts*
 RustaceanLspClientOpts                                  *RustaceanLspClientOpts*
 
     Fields: ~
-        {auto_attach?}           (boolean|fun(bufnr:integer):boolean)                               Whether to automatically attach the LSP client. Defaults to `true` if the `rust-analyzer` executable is found.
-        {cmd?}                   (string[]|fun():string[])                                          Command and arguments for starting rust-analyzer
-        {settings?}              (table|fun(project_root:string|nil,default_settings:table):table)  Setting passed to rust-analyzer. Defaults to a function that looks for a `rust-analyzer.json` file or returns an empty table. See https://rust-analyzer.github.io/manual.html#configuration.
-        {standalone?}            (boolean)                                                          Standalone file support (enabled by default). Disabling it may improve rust-analyzer's startup time.
-        {logfile?}               (string)                                                           The path to the rust-analyzer log file.
-        {load_vscode_settings?}  (boolean)                                                          Whether to search (upward from the buffer) for rust-analyzer settings in .vscode/settings json. If found, loaded settings will override configured options. Default: false
+        {auto_attach?}           (boolean|fun(bufnr:integer):boolean)                                              Whether to automatically attach the LSP client. Defaults to `true` if the `rust-analyzer` executable is found.
+        {cmd?}                   (string[]|fun():string[])                                                         Command and arguments for starting rust-analyzer
+        {root_dir?}              (string|fun(filename:string,default:fun(filename:string):string|nil):string|nil)  The directory to use for the attached LSP. Can be a function, which may return nil if no server should attach. The second argument contains the default implementation, which can be used for fallback behavior.
+        {settings?}              (table|fun(project_root:string|nil,default_settings:table):table)                 Setting passed to rust-analyzer. Defaults to a function that looks for a `rust-analyzer.json` file or returns an empty table. See https://rust-analyzer.github.io/manual.html#configuration.
+        {standalone?}            (boolean)                                                                         Standalone file support (enabled by default). Disabling it may improve rust-analyzer's startup time.
+        {logfile?}               (string)                                                                          The path to the rust-analyzer log file.
+        {load_vscode_settings?}  (boolean)                                                                         Whether to search (upward from the buffer) for rust-analyzer settings in .vscode/settings json. If found, loaded settings will override configured options. Default: false
 
 
 RustaceanDapOpts                                              *RustaceanDapOpts*

lua/rustaceanvim/cargo.lua

@@ -27,13 +27,29 @@ local function get_mb_active_client_root(file_name)
   end
 end
 
+---Attempts to find the root for an existing active client. If no existing
+---client root is found, returns the result of evaluating `config.root_dir`.
+---@param config RustaceanLspClientConfig
 ---@param file_name string
 ---@return string | nil root_dir
-function cargo.get_root_dir(file_name)
+function cargo.get_config_root_dir(config, file_name)
   local reuse_active = get_mb_active_client_root(file_name)
   if reuse_active then
     return reuse_active
   end
+
+  local config_root_dir = config.root_dir
+  if type(config_root_dir) == 'function' then
+    return config_root_dir(file_name, cargo.get_root_dir)
+  else
+    return config_root_dir
+  end
+end
+
+---The default implementation used for `vim.g.rustaceanvim.server.root_dir`
+---@param file_name string
+---@return string | nil root_dir
+function cargo.get_root_dir(file_name)
   local path = file_name:find('%.rs$') and vim.fs.dirname(file_name) or file_name
   if not path then
     return nil

lua/rustaceanvim/config/check.lua

@@ -89,6 +89,7 @@ function M.validate(cfg)
     cmd = { server.cmd, { 'function', 'table' } },
     standalone = { server.standalone, 'boolean' },
     settings = { server.settings, { 'function', 'table' }, true },
+    root_dir = { server.root_dir, { 'function', 'string' } },
   })
   if not ok then
     return false, err

lua/rustaceanvim/config/init.lua

@@ -110,6 +110,7 @@ vim.g.rustaceanvim = vim.g.rustaceanvim
 ---@class RustaceanLspClientOpts
 ---@field auto_attach? boolean | fun(bufnr: integer):boolean Whether to automatically attach the LSP client. Defaults to `true` if the `rust-analyzer` executable is found.
 ---@field cmd? string[] | fun():string[] Command and arguments for starting rust-analyzer
+---@field root_dir? string | fun(filename: string, default: fun(filename: string):string|nil):string|nil The directory to use for the attached LSP. Can be a function, which may return nil if no server should attach. The second argument contains the default implementation, which can be used for fallback behavior.
 ---@field settings? table | fun(project_root:string|nil, default_settings: table):table Setting passed to rust-analyzer. Defaults to a function that looks for a `rust-analyzer.json` file or returns an empty table. See https://rust-analyzer.github.io/manual.html#configuration.
 ---@field standalone? boolean Standalone file support (enabled by default). Disabling it may improve rust-analyzer's startup time.
 ---@field logfile? string The path to the rust-analyzer log file.

lua/rustaceanvim/config/internal.lua

@@ -1,4 +1,5 @@
 local types = require('rustaceanvim.types.internal')
+local cargo = require('rustaceanvim.cargo')
 local compat = require('rustaceanvim.compat')
 local config = require('rustaceanvim.config')
 local executors = require('rustaceanvim.executors')
@@ -275,6 +276,10 @@ local RustaceanDefaultConfig = {
     cmd = function()
       return { 'rust-analyzer', '--log-file', RustaceanConfig.server.logfile }
     end,
+
+    ---@type string | fun(filename: string, default: fun(filename: string):string|nil):string|nil
+    root_dir = cargo.get_root_dir,
+
     --- standalone file support
     --- setting it to false may improve startup time
     ---@type boolean

lua/rustaceanvim/lsp.lua

@@ -95,7 +95,7 @@ M.start = function(bufnr)
   local client_config = config.server
   ---@type LspStartConfig
   local lsp_start_config = vim.tbl_deep_extend('force', {}, client_config)
-  local root_dir = cargo.get_root_dir(bufname)
+  local root_dir = cargo.get_config_root_dir(client_config, bufname)
   if not root_dir then
     --- No project root found. Start in detached/standalone mode.
     root_dir = vim.fs.dirname(bufname)

lua/rustaceanvim/neotest/init.lua

@@ -27,12 +27,13 @@
 
 ---@diagnostic disable: duplicate-set-field
 
+local cargo = require('rustaceanvim.cargo')
+local compat = require('rustaceanvim.compat')
+local config = require('rustaceanvim.config.internal')
 local lib = require('neotest.lib')
 local nio = require('nio')
-local trans = require('rustaceanvim.neotest.trans')
-local cargo = require('rustaceanvim.cargo')
 local overrides = require('rustaceanvim.overrides')
-local compat = require('rustaceanvim.compat')
+local trans = require('rustaceanvim.neotest.trans')
 
 ---@package
 ---@type neotest.Adapter
@@ -42,7 +43,7 @@ local NeotestAdapter = { name = 'rustaceanvim' }
 ---@param file_name string
 ---@return string | nil
 NeotestAdapter.root = function(file_name)
-  return cargo.get_root_dir(file_name)
+  return cargo.get_config_root_dir(config.server, file_name)
 end
 
 ---@package