Unattended-upgrades failed to install exim4-daemon-heavy 4.89-2+deb9u4

[Phil Endecott]

Dear Debian Exim people,

I have a system running exim4-daemon-heavy on Stretch 
with unattended-upgrades.  This morning I checked to see 
if the security upgrade to 4.89-2+deb9u4 had been 
installed and I found this:

$ dpkg -l '*exim*'
(edited output)
ii  exim4-base             4.89-2+deb9u4    amd64
ii  exim4-config           4.89-2+deb9u4    all
ii  exim4-daemon-heavy     4.89-2+deb9u3    amd64

Note the daemon-heavy package has not been upgraded.

# tail /var/log/unattended-upgrades/unattended-upgrades.log
2019-06-06 06:24:33,290 INFO Starting unattended upgrades script
2019-06-06 06:24:33,290 INFO Allowed origins are: ['origin=Debian,codename=stretch,label=Debian-Security']
2019-06-06 06:24:38,294 INFO Packages that will be upgraded: exim4-base exim4-config exim4-daemon-heavy
2019-06-06 06:24:38,296 INFO Writing dpkg log to '/var/log/unattended-upgrades/unattended-upgrades-dpkg.log'
2019-06-06 06:24:42,017 INFO All upgrades installed

# tail /var/log/unattended-upgrades/unattended-upgrades-dpkg.log
Log started: 2019-06-06  06:24:38
apt-listchanges: Reading changelogs...
Preconfiguring packages ...
(Reading database ... 131863 files and directories currently installed.)
Preparing to unpack .../exim4-config_4.89-2+deb9u4_all.deb ...
Unpacking exim4-config (4.89-2+deb9u4) over (4.89-2+deb9u3) ...
Preparing to unpack .../exim4-base_4.89-2+deb9u4_amd64.deb ...
Unpacking exim4-base (4.89-2+deb9u4) over (4.89-2+deb9u3) ...
Setting up exim4-config (4.89-2+deb9u4) ...
Setting up exim4-base (4.89-2+deb9u4) ...
Processing triggers for systemd (232-25+deb9u11) ...
Processing triggers for man-db (2.7.6.1-2) ...
Log ended: 2019-06-06  06:24:42

So unattended-upgrades.log lists exim4-daemon-heavy as "will be upgraded", 
and also reports "All upgrades installed", but unattended-upgrades-dpkg.log 
doesn't mention it at all.

It did install when I tried manually:

# apt-get install exim4-daemon-heavy
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following additional packages will be installed:
  libmariadbclient18
The following packages will be upgraded:
  exim4-daemon-heavy libmariadbclient18
2 upgraded, 0 newly installed, 0 to remove and 112 not upgraded.
Need to get 1,378 kB of archives.
After this operation, 7,168 B of additional disk space will be used.
Do you want to continue? [Y/n] 
Get:1 http://security.debian.org/debian-security stretch/updates/main amd64 exim4-daemon-heavy amd64 4.89-2+deb9u4 [593 kB]
Get:2 http://cdn-aws.deb.debian.org/debian stretch/main amd64 libmariadbclient18 amd64 10.1.38-0+deb9u1 [785 kB]
Fetched 1,378 kB in 0s (15.7 MB/s)                                              
Reading changelogs... Done
Preconfiguring packages ...
(Reading database ... 131863 files and directories currently installed.)
Preparing to unpack .../libmariadbclient18_10.1.38-0+deb9u1_amd64.deb ...
Unpacking libmariadbclient18:amd64 (10.1.38-0+deb9u1) over (10.1.37-0+deb9u1) ...
Preparing to unpack .../exim4-daemon-heavy_4.89-2+deb9u4_amd64.deb ...
Unpacking exim4-daemon-heavy (4.89-2+deb9u4) over (4.89-2+deb9u3) ...
Setting up libmariadbclient18:amd64 (10.1.38-0+deb9u1) ...
Processing triggers for libc-bin (2.24-11+deb9u3) ...
Setting up exim4-daemon-heavy (4.89-2+deb9u4) ...
Updating GnuTLS DH parameter file
Processing triggers for man-db (2.7.6.1-2) ...

Note that that has also installed a new libmariadbclient18.  Is 
that what caused the problem for unattended-upgrades?  Is it OK 
for this security update to require a new version of a library?


(Please Cc: me in any replies.)

Regards,  Phil.