3 files changed, 70 insertions, 6 deletions
diff --git a/runtime/lua/vim/lsp/buf.lua b/runtime/lua/vim/lsp/buf.lua
index 264d7c0247..8bfcd90f12 100644
--- a/runtime/lua/vim/lsp/buf.lua
+++ b/runtime/lua/vim/lsp/buf.lua
@@ -249,13 +249,34 @@ end
 ---@param new_name (string) If not provided, the user will be prompted for a new
 ---name using |input()|.
 function M.rename(new_name)
-  -- TODO(ashkan) use prepareRename
-  -- * result: [`Range`](#range) \| `{ range: Range, placeholder: string }` \| `null` describing the range of the string to rename and optionally a placeholder text of the string content to be renamed. If `null` is returned then it is deemed that a 'textDocument/rename' request is not valid at the given position.
   local params = util.make_position_params()
-  new_name = new_name or npcall(vfn.input, "New Name: ", vfn.expand('<cword>'))
-  if not (new_name and #new_name > 0) then return end
-  params.newName = new_name
-  request('textDocument/rename', params)
+  local function prepare_rename(err, result)
+    if err == nil and result == nil then
+      vim.notify('nothing to rename', vim.log.levels.INFO)
+      return
+    end
+    if result and result.placeholder then
+      new_name = new_name or npcall(vfn.input, "New Name: ", result.placeholder)
+    elseif result and result.start and result['end'] and
+      result.start.line == result['end'].line then
+      local line = vfn.getline(result.start.line+1)
+      local start_char = result.start.character+1
+      local end_char = result['end'].character
+      new_name = new_name or npcall(vfn.input, "New Name: ", string.sub(line, start_char, end_char))
+    else
+      -- fallback to guessing symbol using <cword>
+      --
+      -- this can happen if the language server does not support prepareRename,
+      -- returns an unexpected response, or requests for "default behavior"
+      --
+      -- see https://microsoft.github.io/language-server-protocol/specification#textDocument_prepareRename
+      new_name = new_name or npcall(vfn.input, "New Name: ", vfn.expand('<cword>'))
+    end
+    if not (new_name and #new_name > 0) then return end
+    params.newName = new_name
+    request('textDocument/rename', params)
+  end
+  request('textDocument/prepareRename', params, prepare_rename)
 end
 
 --- Lists all the references to the symbol under the cursor in the quickfix window.
diff --git a/runtime/lua/vim/lsp/health.lua b/runtime/lua/vim/lsp/health.lua
new file mode 100644
index 0000000000..855679a2df
--- /dev/null
+++ b/runtime/lua/vim/lsp/health.lua
@@ -0,0 +1,27 @@
+local M = {}
+
+--- Performs a healthcheck for LSP
+function M.check_health()
+  local report_info = vim.fn['health#report_info']
+  local report_warn = vim.fn['health#report_warn']
+
+  local log = require('vim.lsp.log')
+  local current_log_level = log.get_level()
+  local log_level_string = log.levels[current_log_level]
+  report_info(string.format("LSP log level : %s", log_level_string))
+
+  if current_log_level < log.levels.WARN then
+    report_warn(string.format("Log level %s will cause degraded performance and high disk usage", log_level_string))
+  end
+
+  local log_path = vim.lsp.get_log_path()
+  report_info(string.format("Log path: %s", log_path))
+
+  local log_size = vim.loop.fs_stat(log_path).size
+
+  local report_fn = (log_size / 1000000 > 100 and report_warn or report_info)
+  report_fn(string.format("Log size: %d KB", log_size / 1000 ))
+end
+
+return M
+
diff --git a/runtime/lua/vim/lsp/log.lua b/runtime/lua/vim/lsp/log.lua
index a2d5c3a774..5d2e396cc5 100644
--- a/runtime/lua/vim/lsp/log.lua
+++ b/runtime/lua/vim/lsp/log.lua
@@ -32,6 +32,17 @@ do
 
   vim.fn.mkdir(vim.fn.stdpath('cache'), "p")
   local logfile = assert(io.open(logfilename, "a+"))
+
+  local log_info = vim.loop.fs_stat(logfilename)
+  if log_info and log_info.size > 1e9 then
+    local warn_msg = string.format(
+      "LSP client log is large (%d MB): %s",
+      log_info.size / (1000 * 1000),
+      logfilename
+    )
+    vim.notify(warn_msg)
+  end
+
   -- Start message for logging
   logfile:write(string.format("[ START ] %s ] LSP logging initiated\n", os.date(log_date_format)))
   for level, levelnr in pairs(log.levels) do
@@ -88,6 +99,11 @@ function log.set_level(level)
   end
 end
 
+--- Gets the current log level.
+function log.get_level()
+  return current_log_level
+end
+
 --- Checks whether the level is sufficient for logging.
 ---@param level number log level
 ---@returns (bool) true if would log, false if not