patch 8.0.1391: encoding empty string to JSON sometimes gives "null" commit https://github.com/vim/vim/commit/b29d328eb403a243431f4d0d5b360b4ac46bbc3e Author: Bram Moolenaar <Bram@vim.org> Date: Fri Dec 15 21:25:01 2017 +0100 patch 8.0.1391: encoding empty string to JSON sometimes gives "null" Problem: Encoding empty string to JSON sometimes gives "null". Solution: Handle NULL string as empty string. (closes https://github.com/vim/vim/issues/2446)