commit https://github.com/vim/vim/commit/707659490d35e8d66e8bbdcfd93b12dc1387d86c Author: Bram Moolenaar <Bram@vim.org> Date: Sun Feb 28 19:28:59 2016 +0100 patch 7.4.1451 Problem: Vim hangs when a channel has a callback but isn't referenced. Solution: Have channel_unref() only return TRUE when the channel was actually freed.