SIGHUP seems to not be propagated to inner child processes

[davoclavo]

Howdy! First of all, I am a recent just convert and I am loving it. Thanks for all the work into this amazing tool.

I have been using a mix of just and zellij to handle some of my workflows, and noticed that when I close a zellij pane running a just recipe it leaves the process alive.

Summary: It seems that a SIGHUP signal is being sent to just, but that signal is not being propagated to the inner child process, which causes the whole process tree to be left alive.

Here is a basic way to reproduce this issue using a simple bash script:

just --version

just 1.16.0

sighup.sh

#!/bin/bash

# Define a function to handle SIGHUP
handle_sighup() {
 echo "Received SIGHUP"
 exit 1
}

# Register the function as a signal handler
trap handle_sighup SIGHUP

# Main program loop
while true; do
 sleep 1
done

justfile

sighup:
  bash ./sighup.sh

Problematic behaviour:

# Run recipe and send it to the background
just sighup &

# Attempt to SIGHUP the `just` process
kill -1 $(pgrep -f 'just sighup')
# Problem here: Nothing happens!

# Attempt to SIGHUP the child process directly
kill -1 $(pgrep -f 'bash ./sighup.sh')
# Got the following expected stdout output
Received SIGHUP
[1]  + 21612 exit 130   just sighup

Expected behaviour:

# Run recipe and send it to the background
just sighup &

# Attempt to SIGHUP the just process
kill -1 $(pgrep -f 'just sighup')

# Get the following expected stdout output and process termination
Received SIGHUP
[1]  + 21612 exit 130   just sighup

Happy to contribute a fix for this, but wanted to check in first if this is something worth fixing, or is it an expected behaviour? Also, any pointers on where to look for would be appreciated.

[davoclavo]

This issue also might be related to these other issues:

#1558
#1560

[damccull]

I'm also experiencing this when using just to launch tasks inside of zellij. I would love to see a fix for this. For now I'm going to have to adjust my zellij layout to launch the commands directly instead of using just. Hopefully can migrate back soon.

[kuglee]

I've also ran into this and it's not ideal. I'd be great to have a fix/option for this.

[casey]

Closing in favor of #2473, where I tried to collect everything related to signal handling in one place. I'm not able to reproduce processes being left behind when just is run inside of zellij. If I run just with a recipe that calls sleep 100 inside a zellij tab, closing that tab doesn't leave behind any processes, which is expected, since even if just ignores SIGHUP, it should be sent to all child processes, so sleep 100 should get it, and just should terminate when it exits. A reproduction would be great!

Currently, just is ignoring SIGHUP sent to it directly. However, I'm not sure if this is a problem, since SIGHUP, when the terminal is closed, should be sent to all child processes, so the child should get it, terminate, and then just should terminate.