Comment 7 for bug 1814543

Reverified with 1.7.4 and 1.6.10

$ lxc exec apt-bionic -- apt -o AptCli::Hooks::Install::="/usr/bin/printf '{error should be json}\n\n' >&3" install
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following package was automatically installed and is no longer required:
  libfreetype6
Use 'apt autoremove' to remove it.
E: Hook /usr/bin/printf '{error should be json}\n\n' >&3 reported an error during hello: {error should be json}
E: Hook /usr/bin/printf '{error should be json}\n\n' >&3 reported an error during hello: {error should be json}

$ lxc exec apt-cosmic -- apt -o AptCli::Hooks::Install::="/usr/bin/printf '{error should be json}\n\n' >&3" install
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following package was automatically installed and is no longer required:
  libfreetype6
Use 'apt autoremove' to remove it.
E: Hook /usr/bin/printf '{error should be json}\n\n' >&3 reported an error during hello: {error should be json}
E: Hook /usr/bin/printf '{error should be json}\n\n' >&3 reported an error during hello: {error should be json}