Function setProcessGroup

internal/tools/bash_unix.go:14–23

setProcessGroup gives the shell its own process group and a Cancel that SIGKILLs the whole group. Without it, backgrounded children (`cmd &`) outlive the shell on cancel or timeout, the leak we prevent. Unix-only: Setpgid and negative-PID Kill aren't portable (Windows has its own build).

(cmd *exec.Cmd)

// the shell on cancel or timeout, the leak we prevent. Unix-only: Setpgid and
// negative-PID Kill aren't portable (Windows has its own build).
func setProcessGroup(cmd *exec.Cmd) {
	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
	cmd.Cancel = func() error {
		if cmd.Process == nil {
			return nil
		}
		// Negative pid targets the whole group (shell is the leader).
		return syscall.Kill(-cmd.Process.Pid, syscall.SIGKILL)
	}
}