Allow to set multiple email invoice recipients (Z#23190766)

src/pretix/base/services/invoices.py

@@ -531,7 +531,7 @@ def send_invoices_to_organizer(sender, **kwargs):
                 if i.event.settings.invoice_email_organizer:
                     with language(i.event.settings.locale):
                         mail(
-                            email=i.event.settings.invoice_email_organizer,
+                            email=[e.strip() for e in i.event.settings.invoice_email_organizer.split(",")],
                             subject=_('New invoice: {number}').format(number=i.number),
                             template=LazyI18nString.from_gettext(_(
                                 'Hello,\n\n'

src/pretix/base/settings.py

@@ -71,6 +71,7 @@ from pretix.base.reldate import (
     RelativeDateField, RelativeDateTimeField, RelativeDateWrapper,
     SerializerRelativeDateField, SerializerRelativeDateTimeField,
 )
+from pretix.base.validators import multimail_validate
 from pretix.control.forms import (
     ExtFileField, FontSelect, MultipleLanguagesWidget, SingleLanguageWidget,
 )
@@ -1233,14 +1234,18 @@ DEFAULTS = {
     'invoice_email_organizer': {
         'default': '',
         'type': str,
-        'form_class': forms.EmailField,
-        'serializer_class': serializers.EmailField,
+        'form_class': forms.CharField,
+        'serializer_class': serializers.CharField,
         'form_kwargs': dict(
             label=_("Email address to receive a copy of each invoice"),
             help_text=_("Each newly created invoice will be sent to this email address shortly after creation. You can "
                         "use this for an automated import of invoices to your accounting system. The invoice will be "
                         "the only attachment of the email."),
-        )
+            validators=[multimail_validate],
+        ),
+        'serializer_kwargs': dict(
+            validators=[multimail_validate],
+        ),
     },
     'show_items_outside_presale_period': {
         'default': 'True',