Comment 0 for bug 1657440

# apt --version
apt 1.2.18 (amd64)

xenial

I got myself into a situation where a repository has a Release and a Release.gpg file, but apt is just ignoring the gpg one and won't download it via apt update for some reason:

The repository in question is http://ubuntu-cloud.archive.canonical.com/ubuntu/dists/xenial-updates/newton/. See how locally I have just the Release file:

root@juju-cb14ed-0-lxd-3:/var/lib/apt/lists# l *Release*
-rw-r--r-- 1 root root 100K Jan 15 18:03 archive.ubuntu.com_ubuntu_dists_xenial-backports_InRelease
-rw-r--r-- 1 root root 242K Apr 21 2016 archive.ubuntu.com_ubuntu_dists_xenial_InRelease
-rw-r--r-- 1 root root 100K Jan 18 11:42 archive.ubuntu.com_ubuntu_dists_xenial-updates_InRelease
-rw-r--r-- 1 root root 100K Jan 18 11:42 security.ubuntu.com_ubuntu_dists_xenial-security_InRelease
-rw-r--r-- 1 root root 7.7K Jan 18 11:45 ubuntu-cloud.archive.canonical.com_ubuntu_dists_xenial-updates_newton_Release

Now I try an update. See how the Release.gpg file gets a "Hit:" instead of a "Get:":
root@juju-cb14ed-0-lxd-3:/var/lib/apt/lists# apt update
Get:1 http://security.ubuntu.com/ubuntu xenial-security InRelease [102 kB]
Hit:2 http://archive.ubuntu.com/ubuntu xenial InRelease
Ign:3 http://ubuntu-cloud.archive.canonical.com/ubuntu xenial-updates/newton InRelease
Get:4 http://archive.ubuntu.com/ubuntu xenial-updates InRelease [102 kB]
Hit:5 http://ubuntu-cloud.archive.canonical.com/ubuntu xenial-updates/newton Release
Get:6 http://ubuntu-cloud.archive.canonical.com/ubuntu xenial-updates/newton Release.gpg [543 B]
Hit:7 http://archive.ubuntu.com/ubuntu xenial-backports InRelease
Fetched 205 kB in 0s (395 kB/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done
8 packages can be upgraded. Run 'apt list --upgradable' to see them.

And I can't install packages:
root@juju-cb14ed-0-lxd-3:/var/lib/apt/lists# apt dist-upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following NEW packages will be installed:
  python3-setuptools
The following packages will be upgraded:
  dh-python dnsmasq-base python-pkg-resources python-setuptools python3-cryptography python3-pkg-resources python3-requests python3-urllib3
8 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 1,193 kB of archives.
After this operation, 808 kB of additional disk space will be used.
Do you want to continue? [Y/n]
WARNING: The following packages cannot be authenticated!
  dh-python dnsmasq-base python-setuptools python-pkg-resources python3-pkg-resources python3-setuptools python3-cryptography python3-requests python3-urllib3
Install these packages without verification? [y/N] n
E: Some packages could not be authenticated
root@juju-cb14ed-0-lxd-3:/var/lib/apt/lists#

Somehow apt is thinking it has the Release.gpg file, but it doesn't?

This server is behind a squid proxy.