post_upgrade() {
  if usr/bin/pacman-key -l >/dev/null 2>&1; then
    export GNUPGHOME="$(pacman-conf gpgdir)"
    usr/bin/pacman-key --populate msys2
    usr/bin/gpgconf --kill all
  fi
}

post_install() {
  if [ -x usr/bin/pacman-key ]; then
    post_upgrade
  fi
}