feat: migrate to vim.lsp.config #3659

Problem:
Nvim 0.11 has vim.lsp.config, which mostly replaces the legacy
nvim-lspconfig "framework".

Solution:
Migrate all configs to `lsp/*` variants. The old configs in
`lua/lspconfig/` are "frozen".

The new configs include these changes:
- `commands` field became raw calls to
  `vim.api.nvim_buf_create_user_command` inside `on_attach`.
- `root_dir` became:
  - `root_markers` whenever the file list was simple didn't need to mach `*`
  - if the logic was complicated, or needed to match something like
    '\*.c', it was defined as a vim.lsp.Config `root_dir` callback.
- `on_config_change` became `before_init`. I don't actually know if this
  is the correct approach, but looking around the documentation of
  `nvim-lspconfig` a saw that it was defined as the function that gets
  called as soon as the config have `root_dir`, and so I thought
  `before_init` might be the closest alternative.
- `docs.description` became a luadoc `@brief` docstring.
- `single_file_support = false`?

Co-authored-by: Aliou Diallo <aliou@users.noreply.github.com>
Co-authored-by: Justin M. Keyes <justinkz@gmail.com>

1 files changed, 118 insertions, 0 deletions

diff --git a/lsp/rust_analyzer.lua b/lsp/rust_analyzer.lua
new file mode 100644
index 00000000..c14df89d
--- /dev/null
+++ b/lsp/rust_analyzer.lua
@@ -0,0 +1,118 @@
+local util = require 'lspconfig.util'
+
+local function reload_workspace(bufnr)
+  bufnr = util.validate_bufnr(bufnr)
+  local clients = vim.lsp.get_clients { bufnr = bufnr, name = 'rust_analyzer' }
+  for _, client in ipairs(clients) do
+    vim.notify 'Reloading Cargo Workspace'
+    client.request('rust-analyzer/reloadWorkspace', nil, function(err)
+      if err then
+        error(tostring(err))
+      end
+      vim.notify 'Cargo workspace reloaded'
+    end, 0)
+  end
+end
+
+local function is_library(fname)
+  local user_home = vim.fs.normalize(vim.env.HOME)
+  local cargo_home = os.getenv 'CARGO_HOME' or user_home .. '/.cargo'
+  local registry = cargo_home .. '/registry/src'
+  local git_registry = cargo_home .. '/git/checkouts'
+
+  local rustup_home = os.getenv 'RUSTUP_HOME' or user_home .. '/.rustup'
+  local toolchains = rustup_home .. '/toolchains'
+
+  for _, item in ipairs { toolchains, registry, git_registry } do
+    if util.path.is_descendant(item, fname) then
+      local clients = vim.lsp.get_clients { name = 'rust_analyzer' }
+      return #clients > 0 and clients[#clients].config.root_dir or nil
+    end
+  end
+end
+
+---@brief
+---
+---https://github.com/rust-lang/rust-analyzer
+--
+-- rust-analyzer (aka rls 2.0), a language server for Rust
+--
+--
+-- See [docs](https://rust-analyzer.github.io/book/configuration.html) for extra settings. The settings can be used like this:
+-- ```lua
+-- vim.lsp.config('rust_analyzer', {
+--   settings = {
+--     ['rust-analyzer'] = {
+--       diagnostics = {
+--         enable = false;
+--       }
+--     }
+--   }
+-- })
+-- ```
+--
+-- Note: do not set `init_options` for this LS config, it will be automatically populated by the contents of settings["rust-analyzer"] per
+-- https://github.com/rust-lang/rust-analyzer/blob/eb5da56d839ae0a9e9f50774fa3eb78eb0964550/docs/dev/lsp-extensions.md?plain=1#L26.
+return {
+  cmd = { 'rust-analyzer' },
+  filetypes = { 'rust' },
+  root_dir = function(bufnr, on_dir)
+    local fname = vim.api.nvim_buf_get_name(bufnr)
+    local reuse_active = is_library(fname)
+    if reuse_active then
+      return reuse_active
+    end
+
+    local cargo_crate_dir = util.root_pattern 'Cargo.toml'(fname)
+    local cargo_workspace_root
+
+    if cargo_crate_dir == nil then
+      on_dir(
+        util.root_pattern 'rust-project.json'(fname)
+          or vim.fs.dirname(vim.fs.find('.git', { path = fname, upward = true })[1])
+      )
+      return
+    end
+
+    local cmd = {
+      'cargo',
+      'metadata',
+      '--no-deps',
+      '--format-version',
+      '1',
+      '--manifest-path',
+      cargo_crate_dir .. '/Cargo.toml',
+    }
+
+    vim.system(cmd, { text = true }, function(output)
+      if output.code == 0 then
+        if output.stdout then
+          local result = vim.json.decode(output.stdout)
+          if result['workspace_root'] then
+            cargo_workspace_root = vim.fs.normalize(result['workspace_root'])
+          end
+        end
+
+        on_dir(cargo_workspace_root or cargo_crate_dir)
+      else
+        vim.notify(('[rust_analyzer] cmd failed with code %d: %s\n%s'):format(output.code, cmd, output.stderr))
+      end
+    end)
+  end,
+  capabilities = {
+    experimental = {
+      serverStatusNotification = true,
+    },
+  },
+  before_init = function(init_params, config)
+    -- See https://github.com/rust-lang/rust-analyzer/blob/eb5da56d839ae0a9e9f50774fa3eb78eb0964550/docs/dev/lsp-extensions.md?plain=1#L26
+    if config.settings and config.settings['rust-analyzer'] then
+      init_params.initializationOptions = config.settings['rust-analyzer']
+    end
+  end,
+  on_attach = function()
+    vim.api.nvim_buf_create_user_command(0, 'CargoReload', function()
+      reload_workspace(0)
+    end, { desc = 'Reload current cargo workspace' })
+  end,
+}