FZF blocks Vim while opened in tmux pane

[kodemeister]

• Category
  • fzf binary
  • fzf-tmux script
  • Key bindings
  • Completion
  • Vim
  • Neovim
  • Etc.
• OS
  • Linux
  • Mac OS X
  • Windows
  • Windows Subsystem for Linux
  • Etc.
• Shell
  • bash
  • zsh
  • fish

Steps to reproduce:

1. Run Vim inside tmux
2. Run FZF
3. Switch back to Vim pane
4. Type any characters

Expected: Vim consumes typed characters as usual
Observed: Vim is blocked and typed characters are echoed on the screen until FZF is closed

This issue per se is not so important but it causes another bugs: #434, tmux-plugins/vim-tmux-focus-events#2. With set -g focus-events on tmux sends FocusIn/FocusOut escape sequences (<Esc>[I and <Esc>[O) to Vim instance. But since Vim is blocked by FZF, these escape sequences are echoed on the screen as ^[[I and ^[[O.

By default, Neovim doesn't have such issues because FZF is running asynchronously in separate terminal. But in Vim FZF is invoked with blocking system() call.

https://github.com/junegunn/fzf/blob/master/plugin/fzf.vim#L395

Would it be possible to have the same asynchronous FZF behavior in Vim as well, e.g. by using Vim 8 job API?

[junegunn]

I'm not sure if I want to rewrite Vim plugin to work in asynchronous manner, as it complicates the implementation without obvious benefit (and also because I don't use the tmux plugin). Have you tried the workaround suggested in tmux-plugins/vim-tmux-focus-events#2 (comment)?

[kodemeister]

Yes, I've tried this workaround but unfortunately it doesn't work for me. Once I open FZF, leftover characters begin to appear.

Another affected plugin is https://github.com/christoomey/vim-tmux-navigator. Again, navigation works fine until I open FZF. While it's opened, I can't switch from Vim to other panes using vim-tmux-navigator because Vim is blocked.

I could give async FZF invocation a try using Neovim implementation as an example. At first glance, it doesn't seem to be so hard. Can you please point me out any clues/caveats here?