Comment 3 for bug 1741861

This is still a problem on 18.04.

tj  /  tmp  apt list virt-* --installed
Listing... Done
virt-manager/bionic,bionic,now 1:1.5.0-0ubuntu1 all [installed]
virt-viewer/bionic,now 6.0-2 amd64 [installed,automatic]
 tj  /  tmp  apt list *spice* --installed
Listing... Done
libspice-client-glib-2.0-8/bionic,now 0.34-1.1build1 amd64 [installed,automatic]
libspice-client-gtk-3.0-5/bionic,now 0.34-1.1build1 amd64 [installed,automatic]
libspice-server1/bionic,now 0.14.0-1ubuntu2 amd64 [installed]
spice-client-glib-usb-acl-helper/bionic,now 0.34-1.1build1 amd64 [installed,automatic]
spice-client-gtk/bionic,now 0.34-1.1build1 amd64 [installed]
spice-vdagent/bionic,now 0.17.0-1ubuntu2 amd64 [installed,automatic]

I suspect because the packages are Recommends: not Depends:

  Recommends: gir1.2-spiceclientglib-2.0
  Recommends: gir1.2-spiceclientgtk-3.0

so if --no-install-recommends is used or is set as the default those packages won't be installed.

Changelog says these are Depends.