widgets can only be called when ZLE is active

Question

I have been dealing with this problem for almost a month now, and I feel frustrated, Any help would be greatly appreciated.

I am trying to write a widget for my takenote command. The purpose of the widget is to feed all the markdown files in ~/notes folder into fzf so that the user can select one of them and starts editing it. After the user types takenote and presses <tab> I expect the widget to run.

Here is the _takenote.zsh widget definition:

#compdef takenote
local file=$( find -L "$HOME/notes/" -print 2> /dev/null | fzf-tmux +m )
zle reset-prompt
compadd $file
return 1

Unfortunately, the above code doesn't work because of zle reset-prompt, if I remove it then the result would be like this:

And after selecting the file it would turn into:

Which as you see will corrupt the prompt and the command itself. It appears to me that what I need to do is do a zle reset-prompt before calling compadd but this can only work when I bind the function to a key otherwise, I will get the following error:

widgets can only be called when ZLE is active

Answer 1

I finally found a workaround for the issue. Although I am not satisfied with the strategy since it is not self contained in the widget itself, but it works. The solution involves trapping fzf-completion after it is invoked and calling zle reset-prompt.

For registering the trap add the following snippet to your .zshrc file (see Zsh menu completion causes problems after zle reset-prompt ):

TMOUT=1
TRAPALRM() {
   if [[ "$WIDGET" =~ ^(complete-word|fzf-completion)$ ]]; then
      # limit the reset-prompt functionality to the `takenote` script
      if [[ "$LBUFFER" == "takenote "* ]]; then
         zle reset-prompt
      fi
   fi
}

---

The _takenote widget:

#compdef takenote
local file=$( find -L "$HOME/notes/" -print 2> /dev/null | fzf-tmux +m )
compadd $file
return 0

p.s: I would still love to move the trap inside the widget, and avoid registering it in the init script (.zshrc)

Answer 2

I was getting the same error when trying to use bindkey for a widget to use vim to open the fzf selected file. Turns out I have to open the file in function1 and then have a function2 calling function1 and then reset-prompt to avoid this widgets can only be called when ZLE is active error. Like you said, it is really frustrating and took me almost a day to figure out!

Example code:

## use rg to get file list
export FZF_DEFAULT_COMMAND='rg --files --hidden'

## file open (function1)
__my-fo() (
  setopt localoptions pipefail no_aliases 2> /dev/null
  local file=$(eval "${FZF_DEFAULT_COMMAND}" | FZF_DEFAULT_OPTS="--height ${FZF_TMUX_HEIGHT:-40%} --reverse $FZF_DEFAULT_OPTS --preview 'bat --color=always --line-range :500 {}'" $(__fzfcmd) -m "$@" | while read item; do
    echo -n "${(q)item}"
  done)
  local ret=$?
  if [[ -n $file ]]; then
    $EDITOR $file
  fi
  return $ret
)

## define zsh widget(function2)
__my-fo-widget(){
  __my-fo
  local ret=$?
  zle reset-prompt
  return $ret
}

zle -N __my-fo-widget
bindkey ^p __my-fo-widget

Answer 3

After two days, I finally managed to find a hint on how to achieve it thanks to the excellent fzf-tab-completion project:

https://github.com/lincheney/fzf-tab-completion/blob/c91959d81320935ae88c090fedde8dcf1ca70a6f/zsh/fzf-zsh-completion.sh#L120

So actually, all that you need to do is:

#compdef takenote
local file=$( find -L "$HOME/notes/" -print 2> /dev/null | fzf-tmux +m )
compadd $file
    
TRAPEXIT() {
   zle reset-prompt
}
return 0

And it finally works. Cheers!