patch 8.0.0212: buffer for key name may be too small commit https://github.com/vim/vim/commit/423977d3cebac2be1158b1d11da60fe96db4b750 Author: Bram Moolenaar <Bram@vim.org> Date: Sun Jan 22 15:05:12 2017 +0100 patch 8.0.0212: buffer for key name may be too small Problem: The buffer used to store a key name theoreticaly could be too small. (Coverity) Solution: Count all possible modifier characters. Add a check for the length just in case.

function! Test_WriteFile()
  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")
  let l = readfile(f)
  call assert_equal("hello", l[0])
  call assert_equal("world!", l[1])
  call assert_equal("good", l[2])
  call assert_equal("morning", l[3])
  call assert_equal("vimmers", l[4])
  call delete(f)
endfunction