[Pkg-mailman-hackers] Bug#919970: mailman3: Creating template causes mail to stop sending mail

[Abhijith PA]

Package: mailman3
Version: 3.2.0-4
Severity: important

Hello.

When creating custom templates for mailing list from webapps. The
mailman3 stop distributing mails. Steps to reproduce.

After creating mailing lists.

1. Go to particular list profile by clicking from the landing page
(assuming /postorius/lists/) .
2. Find the templates section and create a new template. ( I created
footer for non-digest regular message )
3. After saving template start sending mail to the list and see the logs.


-- System Information:
Debian Release: buster/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 4.18.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_IN, LC_CTYPE=en_IN (charmap=UTF-8), LANGUAGE=en_IN:en
(charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages mailman3 depends on:
pn  dbconfig-sqlite3 | dbconfig-pgsql | dbconfig-mysql | dbconfig-n  <none>
ii  debconf [debconf-2.0]                                            1.5.69
ii  logrotate
3.14.0-4
ii  lsb-base
9.20170808
ii  python3                                                          3.6.6-1
pn  python3-aiosmtpd                                                 <none>
pn  python3-alembic                                                  <none>
pn  python3-click                                                    <none>
pn  python3-dnspython                                                <none>
pn  python3-falcon                                                   <none>
pn  python3-flufl.bounce                                             <none>
pn  python3-flufl.i18n                                               <none>
pn  python3-flufl.lock                                               <none>
pn  python3-lazr.config                                              <none>
pn  python3-passlib                                                  <none>
pn  python3-psycopg2 | python3-pymysql                               <none>
pn  python3-public                                                   <none>
ii  python3-requests
2.18.4-2
pn  python3-sqlalchemy                                               <none>
pn  python3-zope.component                                           <none>
pn  python3-zope.configuration                                       <none>
pn  python3-zope.event                                               <none>
pn  python3-zope.interface                                           <none>
ii  ucf                                                              3.0038

Versions of packages mailman3 recommends:
ii  exim4-daemon-light [mail-transport-agent]  4.91-7

Versions of packages mailman3 suggests:
ii  chromium [www-browser]                                    69.0.3497.92-1
ii  firefox-esr [www-browser]                                 60.3.0esr-1
pn  mailman3-doc                                              <none>
pn  postgresql | default-mysql-server | virtual-mysql-server  <none>
ii  w3m [www-browser]                                         0.5.3-36+b1