feat: auto-detect the rustc edition

CHANGELOG.md

@@ -14,6 +14,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   when using cargo-nextest 0.9.7 [[#460](https://github.com/mrcjkb/rustaceanvim/issues/460)].
 - Neotest: Disable ansi colour coding in output to ensure output can be parsed.
 - `Rustc unpretty`: Support Windows.
+- Auto-detect the `rustc` edition.
+  This deprecates the `vim.g.rustaceanvim.tools.rustc.edition` option
+  in favour of `vim.g.rustaceanvim.tools.rustc.default_edition`.
 
 ## [5.1.0] - 2024-07-27
 

doc/rustaceanvim.txt

@@ -268,9 +268,10 @@ rustaceanvim.crate-graph.Opts                    *rustaceanvim.crate-graph.Opts*
 rustaceanvim.rustc.Opts                                *rustaceanvim.rustc.Opts*
 
     Fields: ~
-        {edition}  (string)
-                             The edition to use. See https://rustc-dev-guide.rust-lang.org/guides/editions.html.
-                             Default '2021'.
+        {default_edition?}  (string)
+                                      The default edition to use if it cannot be auto-detected.
+                                      See https://rustc-dev-guide.rust-lang.org/guides/editions.html.
+                                      Default '2021'.
 
 
 rustaceanvim.lsp.ClientOpts                        *rustaceanvim.lsp.ClientOpts*

lua/rustaceanvim/cargo.lua

@@ -76,6 +76,29 @@ local function get_cargo_metadata(path)
   return cargo_crate_dir
 end
 
+---@param buf_name? string
+---@return string edition
+function cargo.get_rustc_edition(buf_name)
+  local config = require('rustaceanvim.config.internal')
+  ---@diagnostic disable-next-line: undefined-field
+  if config.tools.rustc.edition then
+    vim.deprecate('vim.g.rustaceanvim.config.tools.edition', 'default_edition', '6.0.0', 'rustaceanvim')
+    ---@diagnostic disable-next-line: undefined-field
+    return config.tools.rustc.edition
+  end
+  buf_name = buf_name or vim.api.nvim_buf_get_name(0)
+  local path = vim.fs.dirname(buf_name)
+  local _, cargo_metadata = get_cargo_metadata(path)
+  local default_edition = config.tools.rustc.default_edition
+  if not cargo_metadata then
+    return default_edition
+  end
+  local package = vim.iter(cargo_metadata.packages or {}):find(function(pkg)
+    return type(pkg.edition) == 'string'
+  end)
+  return package and package.edition or default_edition
+end
+
 ---The default implementation used for `vim.g.rustaceanvim.server.root_dir`
 ---@param file_name string
 ---@return string | nil root_dir
@@ -85,8 +108,7 @@ function cargo.get_root_dir(file_name)
     return nil
   end
   local cargo_crate_dir, cargo_metadata = get_cargo_metadata(path)
-  local cargo_workspace_dir = cargo_metadata and vim.print(cargo_metadata['workspace_root'])
-  return cargo_workspace_dir
+  return cargo_metadata and cargo_metadata.workspace_root
     or cargo_crate_dir
     ---@diagnostic disable-next-line: missing-fields
     or vim.fs.dirname(vim.fs.find({ 'rust-project.json' }, {

lua/rustaceanvim/commands/rustc_unpretty.lua

@@ -1,6 +1,6 @@
 local M = {}
 
-local config = require('rustaceanvim.config.internal')
+local cargo = require('rustaceanvim.cargo')
 local ui = require('rustaceanvim.ui')
 local api = vim.api
 local ts = vim.treesitter
@@ -139,7 +139,7 @@ function M.rustc_unpretty(level)
     '--crate-type',
     'lib',
     '--edition',
-    config.tools.rustc.edition,
+    cargo.get_rustc_edition(),
     '-Z',
     'unstable-options',
     '-Z',

lua/rustaceanvim/config/check.lua

@@ -65,7 +65,7 @@ function M.validate(cfg)
   end
   local rustc = tools.rustc
   ok, err = validate('tools.rustc', {
-    edition = { rustc.edition, 'string' },
+    default_edition = { rustc.default_edition, 'string' },
   })
   if not ok then
     return false, err

lua/rustaceanvim/config/init.lua

@@ -156,9 +156,10 @@ vim.g.rustaceanvim = vim.g.rustaceanvim
 
 ---@class rustaceanvim.rustc.Opts
 ---
----The edition to use. See https://rustc-dev-guide.rust-lang.org/guides/editions.html.
+---The default edition to use if it cannot be auto-detected.
+---See https://rustc-dev-guide.rust-lang.org/guides/editions.html.
 ---Default '2021'.
----@field edition string
+---@field default_edition? string
 
 ---@class rustaceanvim.lsp.ClientOpts
 ---

lua/rustaceanvim/config/internal.lua

@@ -236,7 +236,7 @@ local RustaceanDefaultConfig = {
     ---@class rustaceanvim.rustc.Config
     rustc = {
       ---@type string
-      edition = '2021',
+      default_edition = '2021',
     },
   },