commit https://github.com/vim/vim/commit/174674743d9a2d7361c9cd89836f8dd8651edeeb Author: Bram Moolenaar <Bram@vim.org> Date: Tue Nov 10 17:50:24 2015 +0100 patch 7.4.915 Problem: When removing from 'path' and then adding, a comma may go missing. (Malcolm Rowe) Solution: Fix the check for P_ONECOMMA. (closes #471)

Test for ":options".

STARTTEST
:so small.vim
:let caught = 'ok'
:try
  :options
:catch 
  :let caught = v:throwpoint . "\n" . v:exception
:endtry
:buf 1
:$put =caught
:"
:" Test that changing 'path' keeps two commas.
:set path=foo,,bar
:set path-=bar
:set path+=bar
:$put =&path
:/^result/,$w! test.out
:qa!
ENDTEST

result