Optionally ask for email addresses twice

src/pretix/base/settings.py

@@ -35,6 +35,10 @@ DEFAULTS = {
         'default': 'False',
         'type': bool
     },
+    'order_email_asked_twice': {
+        'default': 'False',
+        'type': bool
+    },
     'invoice_address_asked': {
         'default': 'True',
         'type': bool,

src/pretix/control/forms/event.py

@@ -275,6 +275,11 @@ class EventSettingsForm(SettingsForm):
         required=False,
         widget=forms.CheckboxInput(attrs={'data-checkbox-dependency': '#id_settings-attendee_emails_asked'}),
     )
+    order_email_asked_twice = forms.BooleanField(
+        label=_("Ask for the order email address twice"),
+        help_text=_("Require customers to fill in the primary email address twice to avoid errors."),
+        required=False,
+    )
     max_items_per_order = forms.IntegerField(
         min_value=1,
         label=_("Maximum number of items per order"),

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

@@ -42,6 +42,7 @@
             {% bootstrap_field sform.max_items_per_order layout="horizontal" %}
             {% bootstrap_field sform.attendee_names_asked layout="horizontal" %}
             {% bootstrap_field sform.attendee_names_required layout="horizontal" %}
+            {% bootstrap_field sform.order_email_asked_twice layout="horizontal" %}
             {% bootstrap_field sform.attendee_emails_asked layout="horizontal" %}
             {% bootstrap_field sform.attendee_emails_required layout="horizontal" %}
             {% bootstrap_field sform.cancel_allow_user layout="horizontal" %}

src/pretix/presale/forms/checkout.py

@@ -26,12 +26,23 @@ class ContactForm(forms.Form):
         self.event = kwargs.pop('event')
         super().__init__(*args, **kwargs)
 
+        if self.event.settings.order_email_asked_twice:
+            self.fields['email_repeat'] = forms.EmailField(
+                label=_('E-mail address (repeated)'),
+                help_text=_('Please enter the same email address again to make sure you typed it correctly.')
+            )
+
         responses = contact_form_fields.send(self.event)
         for r, response in sorted(responses, key=lambda r: str(r[0])):
             for key, value in response.items():
                 # We need to be this explicit, since OrderedDict.update does not retain ordering
                 self.fields[key] = value
 
+    def clean(self):
+        if self.event.settings.order_email_asked_twice:
+            if self.cleaned_data['email'] != self.cleaned_data['email_repeat']:
+                raise ValidationError(_('Please enter the same email address twice.'))
+
 
 class InvoiceAddressForm(forms.ModelForm):