How to prevent Vim from clearing history?

Question

Is there way to prevent Vim from clearing history after exiting Vim?

I want to be able to see the changes I made, while I am using Gundo (or UndoTree), even though I quit vim and the terminal and come back to the same file later on?

Answer 1

Use undotree setting for this - :h undotree.txt, :h undodir and :h presistent_undo.

I have it like so:

if has('persistent_undo')
  if exists('$SUDO_USER')
    " don't create root-owned files
    set noundofile
  else
    set undodir=~/.local/tmp/vim/undo//
    " keep undo files out of the way
    set undodir+=~/.vim/tmp/undo//
    set undodir+=.    
    " actually use undo files
    set undofile
  endif
endif

Despite the check for sudo user to not create a undo file owned by root, this sets few dirs for Vim to create undofile (first available will be used). Also this has set undofile to make sure undofile will be used.

I just checked on some config file with UndoTree and there are changes made 11 days ago and I'm sure I did reboot my laptop in between at least 4 times.