Panel listing packages empty, but upgrades are available

[Benjamin Bach]

I have 23 upgrades available, but they don't display in update-manager. See attached screenshot.

See attached screenshot.

Behavior is reproducible.

These are the upgrades that are available:

~ sudo apt upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages were automatically installed and are no longer required:
  linux-headers-4.15.0-33 linux-headers-4.15.0-33-generic
  linux-image-4.15.0-33-generic linux-modules-4.15.0-33-generic
  linux-modules-extra-4.15.0-33-generic
Use 'sudo apt autoremove' to remove them.
The following packages have been kept back:
  nodejs
The following packages will be upgraded:
  firefox firefox-locale-en gir1.2-javascriptcoregtk-4.0 gir1.2-webkit2-4.0
  libbrotli1 libjavascriptcoregtk-4.0-18 liblouis-data liblouis14
  libnautilus-extension1a libplymouth4 libwebkit2gtk-4.0-37 libwoff1 nautilus
  nautilus-data plymouth plymouth-label plymouth-theme-ubuntu-logo
  plymouth-theme-ubuntu-text python3-louis python3-update-manager
  slack-desktop update-manager update-manager-core
23 upgraded, 0 newly installed, 0 to remove and 1 not upgraded.
Need to get 119 MB of archives.
After this operation, 2,797 kB of additional disk space will be used.
Do you want to continue? [Y/n]

[Benjamin Bach (benjaoming)]

Here is the output of running update-manager while reproducing the issue:

update-manager --debug
DEBUG:AptClient.DebconfProxy:debconf socket: /tmp/aptdaemon-fwlr2n2s/debconf.socket
DEBUG:root:debconf.start()
DEBUG:root:debconf.stop()
INFO:root:holding back phased update gnome-software (0 < 100)
INFO:root:holding back phased update gnome-software-common (0 < 100)
DEBUG:root:WARNING: can not get name for '<Gtk.TreeViewAccessible object at 0x7f5364dc8240 (GtkTreeViewAccessible at 0x221cde0)>'
DEBUG:root:WARNING: can not get name for '<Gtk.LabelAccessible object at 0x7f5364dc8990 (GtkLabelAccessible at 0x2688c90)>'
DEBUG:root:WARNING: can not get name for '<Gtk.TreeSelection object at 0x7f5364dc8a68 (GtkTreeSelection at 0x26205c0)>'
DEBUG:root:WARNING: can not get name for '<Gtk.TextViewAccessible object at 0x7f5364dcb240 (GtkTextViewAccessible at 0x38be870)>'

[Benjamin Bach (benjaoming)]

update-manager: version 1:18.04.11.5

Sorry, this report should perhaps be moved to the update-manager package?

[Sebastien Bacher (seb128)]

Yes, the issue is in update-manager

[Steve Langasek (vorlon)]

The pop-up with an empty list of packages to install is bug #1072136 which has just been fixed in update-manager 1:18.04.11.6.

It is by design that no packages are shown for installation in this case; we apply phased updates to SRUs so that they are not all presented to all users at the same time. It is also considered a bug in apt that it does not honor phased updates (but there doesn't appear to be a bug open on the apt package about this).

I'm marking this as a duplicate of bug #1072136.