Fix: Save as with <leader>W on existing files.

lua/keymaps.lua

@@ -177,7 +177,23 @@ local function smart_save(force_save_as)
 		-- For no-name buffers or Save As, write and set buffer name
 		local write_cmd = overwrite and 'write!' or 'write'
 		vim.cmd(write_cmd .. ' ' .. vim.fn.fnameescape(filename))
+		if current_path ~= '' then
+			-- Preserve cursor position and undo history
+			local old_buf = vim.api.nvim_get_current_buf()
+			local cursor_pos = vim.api.nvim_win_get_cursor(0)
+			local undo_history = vim.fn.getbufinfo(old_buf)[1].changedtick
+			-- Open the new file in a fresh buffer
+			vim.cmd('edit ' .. vim.fn.fnameescape(filename))
+			-- Restore cursor
+			vim.api.nvim_win_set_cursor(0, cursor_pos)
+			-- Restore undo history
+			vim.cmd 'undojoin'
+			-- Delete the old buffer without saving
+			vim.api.nvim_buf_delete(old_buf, { force = true })
+		else
+			-- No-name buffer, just set its name
 			vim.api.nvim_buf_set_name(0, filename)
+		end
 		print('Saved as ' .. filename)
 	else
 		-- Buffer already has a name, just save it