commit https://github.com/vim/vim/commit/9f5842e63fc63d438cbffcec503e072a06f74dc2 Author: Bram Moolenaar <Bram@vim.org> Date: Sun May 29 16:17:08 2016 +0200 patch 7.4.1857 Problem: When a channel appends to a buffer that is 'nomodifiable' there is an error but appending is done anyway. Solution: Add the 'modifiable' option. Refuse to write to a 'nomodifiable' when the value is 1.