feat(loader): warn when maplocalleader is changed after init (#1326)

* feat(loader): warn when maplocalleader is changed after init

* docs: default maplocalleader

---------

Co-authored-by: Folke Lemaitre <folke.lemaitre@gmail.com>

README.md

@@ -67,6 +67,7 @@ require("lazy").setup(plugins, opts)
 ```lua
 -- Example using a list of specs with the default options
 vim.g.mapleader = " " -- Make sure to set `mapleader` before lazy so your mappings are correct
+vim.g.maplocalleader = "\\" -- Same for `maplocalleader`
 
 require("lazy").setup({
   "folke/which-key.nvim",
@@ -537,7 +538,7 @@ Any command can have a **bang** to make the command wait till it finished. For e
 if you want to sync lazy from the cmdline, you can use:
 
 ```shell
-$ nvim --headless "+Lazy! sync" +qa
+nvim --headless "+Lazy! sync" +qa
 ```
 
 `opts` is a table with the following key-values:

lua/lazy/core/config.lua

@@ -199,6 +199,9 @@ M.me = nil
 ---@type string
 M.mapleader = nil
 
+---@type string
+M.maplocalleader = nil
+
 function M.headless()
   return #vim.api.nvim_list_uis() == 0
 end
@@ -245,6 +248,7 @@ function M.setup(opts)
   -- disable plugin loading since we do all of that ourselves
   vim.go.loadplugins = false
   M.mapleader = vim.g.mapleader
+  M.maplocalleader = vim.g.maplocalleader
 
   if M.headless() then
     require("lazy.view.commands").setup()

lua/lazy/core/loader.lua

@@ -50,6 +50,7 @@ function M.setup()
     Util.track()
   end
   Config.mapleader = vim.g.mapleader
+  Config.maplocalleader = vim.g.maplocalleader
 
   -- report any warnings & errors
   Config.spec:report()

lua/lazy/manage/reloader.lua

@@ -76,6 +76,13 @@ function M.check(start)
     Config.mapleader = vim.g.mapleader
   end
 
+  if Loader.init_done and Config.maplocalleader ~= vim.g.maplocalleader then
+    vim.schedule(function()
+      require("lazy.core.util").warn("You need to set `vim.g.maplocalleader` **BEFORE** loading lazy")
+    end)
+    Config.maplocalleader = vim.g.maplocalleader
+  end
+
   if not (start or #changes == 0) then
     vim.schedule(function()
       if Config.options.change_detection.notify and not Config.headless() then