nvim: added gopls and adjusted lsp config

vim/.config/nvim/lsp/gopls.lua

@@ -0,0 +1,98 @@
+---@brief
+---
+--- https://github.com/golang/tools/tree/master/gopls
+---
+--- Google's lsp server for golang.
+
+--- @class go_dir_custom_args
+---
+--- @field envvar_id string
+---
+--- @field custom_subdir string?
+
+local mod_cache = nil
+local std_lib = nil
+
+---@param custom_args go_dir_custom_args
+---@param on_complete fun(dir: string | nil)
+local function identify_go_dir(custom_args, on_complete)
+  local cmd = { 'go', 'env', custom_args.envvar_id }
+  vim.system(cmd, { text = true }, function(output)
+    local res = vim.trim(output.stdout or '')
+    if output.code == 0 and res ~= '' then
+      if custom_args.custom_subdir and custom_args.custom_subdir ~= '' then
+        res = res .. custom_args.custom_subdir
+      end
+      on_complete(res)
+    else
+      vim.schedule(function()
+        vim.notify(
+          ('[gopls] identify ' .. custom_args.envvar_id .. ' dir cmd failed with code %d: %s\n%s'):format(
+            output.code,
+            vim.inspect(cmd),
+            output.stderr
+          )
+        )
+      end)
+      on_complete(nil)
+    end
+  end)
+end
+
+---@return string?
+local function get_std_lib_dir()
+  if std_lib and std_lib ~= '' then
+    return std_lib
+  end
+
+  identify_go_dir({ envvar_id = 'GOROOT', custom_subdir = '/src' }, function(dir)
+    if dir then
+      std_lib = dir
+    end
+  end)
+  return std_lib
+end
+
+---@return string?
+local function get_mod_cache_dir()
+  if mod_cache and mod_cache ~= '' then
+    return mod_cache
+  end
+
+  identify_go_dir({ envvar_id = 'GOMODCACHE' }, function(dir)
+    if dir then
+      mod_cache = dir
+    end
+  end)
+  return mod_cache
+end
+
+---@param fname string
+---@return string?
+local function get_root_dir(fname)
+  if mod_cache and fname:sub(1, #mod_cache) == mod_cache then
+    local clients = vim.lsp.get_clients({ name = 'gopls' })
+    if #clients > 0 then
+      return clients[#clients].config.root_dir
+    end
+  end
+  if std_lib and fname:sub(1, #std_lib) == std_lib then
+    local clients = vim.lsp.get_clients({ name = 'gopls' })
+    if #clients > 0 then
+      return clients[#clients].config.root_dir
+    end
+  end
+  return vim.fs.root(fname, 'go.work') or vim.fs.root(fname, 'go.mod') or vim.fs.root(fname, '.git')
+end
+
+return {
+  cmd = { 'gopls' },
+  filetypes = { 'go', 'gomod', 'gowork', 'gotmpl' },
+  root_dir = function(bufnr, on_dir)
+    local fname = vim.api.nvim_buf_get_name(bufnr)
+    get_mod_cache_dir()
+    get_std_lib_dir()
+    -- see: https://github.com/neovim/nvim-lspconfig/issues/804
+    on_dir(get_root_dir(fname))
+  end,
+}

vim/.config/nvim/lua/plugins/rust-config.lua

@@ -10,9 +10,13 @@ vim.keymap.set(
 )
 vim.keymap.set(
   "n",
-  "K",  -- Override Neovim's built-in hover keymap with rustaceanvim's hover actions
+  "K",
   function()
+    if vim.bo.filetype == "rust" then
       vim.cmd.RustLsp({'hover', 'actions'})
+    else
+      vim.lsp.buf.hover()
+    end
   end,
   { silent = true, buffer = bufnr }
 )