commit https://github.com/vim/vim/commit/437905c25d4cedfa16d0f87392e4a000d22362b7 Author: Bram Moolenaar <Bram@vim.org> Date: Tue Apr 26 19:01:05 2016 +0200 patch 7.4.1789 Problem: Cannot use ch_read() in the close callback. Solution: Do not discard the channel if there is readahead. Do not discard readahead if there is a close callback.

Tests for writefile()

STARTTEST
:source small.vim
:%delete _
:let f = tempname()
:call writefile(["over","written"], f, "b")
:call writefile(["hello","world"], f, "b")
:call writefile(["!", "good"], f, "a")
:call writefile(["morning"], f, "ab")
:call writefile(["", "vimmers"], f, "ab")
:bwipeout!
:$put =readfile(f)
:1 delete _
:w! test.out
:call delete(f)
:qa!
ENDTEST