pre-commit script with interactive: true unable to capture user input from console/tty

[marques-work]

I have a simple script that I want to run as a pre-commit hook. It checks if the user is on the main branch, and asks the user to confirm if they really meant to commit directly to main (not everyone on my team has a git prompt that shows the current branch so I thought this would be an easy guard). I don't want to outright deny commits to main because there are valid use cases, so I just want to verify with the user.

Anyway, I've set interactive: true and even tried that in combination with use_stdin: true but the script just hangs and doesn't seem to be receiving any input from the keyboard. I thought this would be simple and straightforward, but apparently not.

I'm using lefthook v1.6.10

My repo is an internal github repo, so I can't link it, but here is what the script looks like:

#!/bin/bash
# vim: sts=2 sw=2 et ai

set -euo pipefail

exec </dev/tty

main() {
  # Get the current branch name
  local branch="$(git rev-parse --abbrev-ref HEAD)"

  # Check if the current branch is main
  if [ 'main' = "$branch" ]; then
    read -r -p 'You are on the `main` branch. Are you sure you want to commit here? [y/N]: ' answer

    if [ 'y' != "$(tr '[:upper:]' '[:lower:]' <<< "$answer")" ]; then
      printf '\e[31;1m[ERROR] %s\e[0m\n' 'Aborted commit!'
      exit 1
    fi
  fi
}

main

And yes, I have tried variations without exec < /dev/tty or with an explicit read -r answer < /dev/tty and neither works.

My lefthook.yml looks like:

pre-commit:
  scripts:
    check-branch.sh:
      runner: bash
      interactive: true

@mrexox any ideas?

[mrexox]

@marques-work , this config should work:

pre-commit:
  scripts:
    check-branch.sh:
      runner: bash
      use_stdin: true
      interactive: true

And no tweak with /dev/tty is required in the script itself. For example, I could make it work with the following script:

read -r -p '[y/N]' answer

if [ "$answer" = "y" ]; then
  echo 'YES'
  exit 0
else
  echo 'NO'
  exit 1
fi

I think it is kind of confusing that both interactive and use_stdin are required. It feels like if we have interactive we probably want to use STDIN too 🤔 . I will rethink this behavior.

Please write back if you get any problems with the configuration.

[marques-work]

Hi @mrexox, so sorry this reply is very late. I created a new repo with just these files, and I still can't get it to work. I installed lefthook 1.6.11 using go's package installer.

I see the same behavior: it prints the prompt and just hangs indefinitely.

It doesn't seem to take any input (typing isn't echoed to the screen, and hitting enter afterward has no effect). I need to hit ctrl-C to abort when this happens.

I wonder if it's either platform specific or if there's something weird with my environment?

I'm on linux (PopOS), running bash 5.1.16(1)-release.

Noteworthy: if I run the script directly in my terminal (not through lefthook), it works as expected.

[marques-work]

Update 2: I created a completely new user on my system with a vanilla .bashrc. It should be running with all defaults -- no customization, completely clean.

Installed golang 1.22.3 and used the same installation method (go's package manager) to install lefthook. Cloned the repo I linked in my previous comment and tried git commit --allow-empty as a test.

Same result -- lefthook just hangs and doesn't accept any input.

[mrexox]

Thank you for providing a repo example. I think I could find the issue and I will try to prepare a fix ASAP.

[mrexox]

Please, check the new 1.6.12 version of lefthook.

[marques-work]

Yes, it works! Thanks so much for the quick fix!

[marques-work]

Update 3: tried with a fresh EC2 (Amazon Linux release 2023.4.20240513) and performed the same test.

Same result (hangs forever):

EC2 is using bash 5.2.15(1)-release.