How push a vimrc change to all open windows without doing anything extra each time?

Question

Is there a way to push out a vimrc change to all open windows and instances of vim without having to write/change any buffers or reopen vim? I'd like vim to be able to behave like a modern day IDE for this as I change my vimrc a lot and am trying to learn more vim scripting.

Answer 1

I use the following autocmd which reloads my .vimrc whenever I've finished editing it and close it.

augroup reloadvimrc
  autocmd!
  " auto source whenever vimrc fully closed
  " nested because (as of vim 8.0 patch 1-823) needed to do ColorScheme cmds
  " autocmd BufWinLeave $MYVIMRC nested source $MYVIMRC 
  autocmd BufWinLeave $HOME/.vimrc nested source $HOME/.vimrc
augroup end

Further, I use the following mapping to make it easy to edit my .vimrc

" \V open ~/.vimrc
" nmap <leader>V :-tabf $MYVIMRC<CR>
" bc neovim
nnoremap <leader>V :-tabf $HOME/.vimrc<CR>
vnoremap <leader>V :-tabf $HOME/.vimrc<CR>

In general, this is going to handle most of the cases you're worried about. My understanding is you can never truly accomplish a full, clean reload without restarting Vim because of items like VimEnter and statefulness.

Answer 2

If your vimrc is reloadable, you can simply do :source $MYVIMRC (I have that bound to a command :Reload, which is bound to a keystroke <leader>r). In practice, this means avoiding messing with local settings, using augroups, and not unconditionally calling colorscheme.

Other tips:

• If you are editing an ftplugin or syntax file, you can usually do :edit to force-reload those in a file you're in (but note that any mappings and settings that were there may stick around)
• If you are working on a file in the plugin directory, you can use :runtime—or, better, :Runtime from tpope's scriptease plugin—to load the file.

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Causing all open instances of vim to do this would be tricky, though. If you could send signals to vim, it might be possible, but I couldn't find a way to make it respond to, e.g., USR1.