Dear Maintainer,

I performed a distribution upgrade from Debian 10 Buster (which runs mailman 3.2.1) to Debian 11 Bullseye (which runs mailman
3.3.1) with the command "apt-get full-upgrade -y" and everything apparently worked properly except at the end of the upgrade when
the following error dialog was generated by the mailman3-web and mailman3-full post-installation scripts:

Setting up mailman3-web (0+20200530-2) ...
Determining localhost credentials from /etc/mysql/debian.cnf: succeeded.
dbconfig-common: writing config to /etc/dbconfig-common/mailman3-web.conf
dbconfig-common: flushing administrative password
sed: -e expression #2, char 77: unterminated `s' command
dpkg: error processing package mailman3-web (--configure):
 installed mailman3-web package post-installation script subprocess returned error exit status 1
dpkg: dependency problems prevent configuration of mailman3-full:
 mailman3-full depends on mailman3-web; however:
  Package mailman3-web is not configured yet.

dpkg: error processing package mailman3-full (--configure):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 mailman3-web
 mailman3-full
E: Sub-process /usr/bin/dpkg returned an error code (1)

Now, every time that I execute "apt-get upgrade" then I continue to get the above error dialog.  Also, the command
"dpkg-reconfigure mailman3-web" generates this output:

/usr/sbin/dpkg-reconfigure: mailman3-web is broken or not fully installed

So, I am now stuck since apt-get is saying that mailman3-web is not configured yet, however, neither apt-get nor dpkg-reconfigure
will successfully configure mailman3-web.

Note the syntax error statement from the above dialog which may be the culprit: "sed: -e expression #2, char 77: unterminated `s' command"

Does anybody have any idea how to fix this?  I would very much appreciate some suggestions.

Thanks,

Gordon Dickens

<snip>
<snip>

Not a fix, but a _very_ _dirty_ workaround:

 sudo mv /var/lib/dpkg/info/mailman3-web.postinst /var/lib/dpkg/info/mailman3-web.postinst.disabled

(Only do this if everything else failed.) After that, try the install again by
running

 sudo apt-get -f install

.  Your can now do dpkg/apt stuff again.  However, you'll have to manually
execute all the needed things /var/lib/dpkg/info/mailman3-web.postinst was
trying to achieve: have a look at that script.

HTH, Bye,

Joost