refactor!: disable netrw by default (#155)

If you use oil and you want to still use netrw, set
`default_file_explorer = false`.

It is nonsensical to both use netrw _and_ have oil hijack directory
buffers (which was the case for the default config). It also causes
undefined behavior and bugs. When `default_file_explorer = true` (the
default) oil will now disable netrw for you.

lua/oil/config.lua

@@ -1,4 +1,7 @@
 local default_config = {
+  -- Oil will take over directory buffers (e.g. `vim .` or `:e src/`)
+  -- Set to false if you still want to use netrw.
+  default_file_explorer = true,
   -- Id is automatically added at the beginning, and name at the end
   -- See :help oil-columns
   columns = {
@@ -23,8 +26,6 @@ local default_config = {
     conceallevel = 3,
     concealcursor = "n",
   },
-  -- Oil will take over directory buffers (e.g. `vim .` or `:e src/`
-  default_file_explorer = true,
   -- Restore window options to previous values when leaving an oil buffer
   restore_win_options = true,
   -- Skip the confirmation popup for simple operations

lua/oil/init.lua

@@ -846,8 +846,13 @@ M.setup = function(opts)
   end, { desc = "Open oil file browser on a directory", nargs = "*", complete = "dir" })
   local aug = vim.api.nvim_create_augroup("Oil", {})
 
-  if config.default_file_explorer and vim.fn.exists("#FileExplorer") then
-    vim.api.nvim_create_augroup("FileExplorer", { clear = true })
+  if config.default_file_explorer then
+    vim.g.loaded_netrw = 1
+    vim.g.loaded_netrwPlugin = 1
+    -- If netrw was already loaded, clear this augroup
+    if vim.fn.exists("#FileExplorer") then
+      vim.api.nvim_create_augroup("FileExplorer", { clear = true })
+    end
   end
 
   local patterns = {}
@@ -967,24 +972,6 @@ M.setup = function(opts)
       end,
     })
   end
-  if
-    vim.g.loaded_netrwPlugin ~= 1
-    and not config.silence_netrw_warning
-    and config.default_file_explorer
-  then
-    vim.api.nvim_create_autocmd("FileType", {
-      desc = "Inform user how to disable netrw",
-      group = aug,
-      pattern = "netrw",
-      once = true,
-      callback = function()
-        vim.notify(
-          "If you expected an Oil buffer here, you may want to disable netrw (:help netrw-noload)\nSet `default_file_explorer = false` in oil.setup() to not take over netrw buffers, or `silence_netrw_warning = true` to disable this message.",
-          vim.log.levels.WARN
-        )
-      end,
-    })
-  end
   vim.api.nvim_create_autocmd("WinNew", {
     desc = "Restore window options when splitting an oil window",
     group = aug,