Added a setting for an e-mail subject prefix

src/pretix/base/services/mail.py

@@ -36,8 +36,13 @@ def mail(user: User, subject: str, template: str, context: dict, event: Event=No
 
     sender = event.settings.get('mail_from') if event else settings.MAIL_FROM
 
+    subject = str(subject)
+    prefix = event.settings.get('mail_prefix')
+    if prefix:
+        subject = "[%s] %s" % (prefix, subject)
+
     email = EmailMessage(
-        str(subject), body, sender,
+        subject, body, sender,
         to=[user.email]
     )
 

src/pretix/base/settings.py

@@ -89,6 +89,10 @@ DEFAULTS = {
         'default': None,
         'type': str
     },
+    'mail_prefix': {
+        'default': None,
+        'type': str
+    },
     'mail_from': {
         'default': settings.MAIL_FROM,
         'type': str

src/pretix/control/forms/event.py

@@ -151,6 +151,11 @@ class EventSettingsForm(SettingsForm):
         required=False,
         help_text=_("Public email address for contacting the organizer")
     )
+    mail_prefix = forms.CharField(
+        label=_("Subject prefix"),
+        help_text=_("This will be prepended to the subject of all outgoing emails. This could be a short form of "
+                    "your event name.")
+    )
     mail_from = forms.EmailField(
         label=_("Sender address"),
         help_text=_("Sender address for outgoing e-mails")

src/pretix/control/templates/pretixcontrol/event/settings.html

@@ -43,6 +43,7 @@
         </fieldset>
         <fieldset>
             <legend>{% trans "E-Mail settings" %}</legend>
+            {% bootstrap_field sform.mail_prefix layout="horizontal" %}
             {% bootstrap_field sform.mail_from layout="horizontal" %}
         </fieldset>
         <div class="form-group submit-group">