commit https://github.com/vim/vim/commit/fcaaae6b3fdbf3421a1ff95a25ae16d82381c39a Author: Bram Moolenaar <Bram@vim.org> Date: Sun Jan 24 16:49:11 2016 +0100 patch 7.4.1166 Problem: Can't encode a Funcref into JSON. jsonencode() doesn't handle the same list or dict twice properly. (Nikolay Pavlov) Solution: Give an error. Reset copyID when the list or dict is finished.

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