From 9dbb8410c1231a7b3e5eb878b256fbece47a3209 Mon Sep 17 00:00:00 2001
From: Erik Stein <erik@classlibrary.net>
Date: Sat, 13 Oct 2018 16:01:45 +0200
Subject: [PATCH] Option to allow empty runtimes (without even a start date).

---
 CHANGES                       | 1 +
 shared/utils/models/events.py | 6 ++++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/CHANGES b/CHANGES
index 3a31be9..c3ee13e 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,5 +1,6 @@
 0.2.13 2018-10-13
 - Improved USE_TRANSLATABLE_FIELDS
+- Option to allow empty runtimes (without even a start date).
 
 0.2.12 2018-09-28
 - Additional text template tags.
diff --git a/shared/utils/models/events.py b/shared/utils/models/events.py
index 8cc5aff..2482d06 100644
--- a/shared/utils/models/events.py
+++ b/shared/utils/models/events.py
@@ -7,8 +7,8 @@ from django.core.exceptions import ValidationError
 from django.db import models
 from django.utils.translation import ugettext_lazy as _
 
-from shared.utils.dateformat import format_partial_date, format_date_range
 from ..conf import USE_TRANSLATABLE_FIELDS
+from ..dateformat import format_partial_date, format_date_range
 
 
 if USE_TRANSLATABLE_FIELDS:
@@ -40,11 +40,13 @@ class RuntimeMixin(models.Model):
         max_length=200, null=True, blank=True,
         help_text=_("Alternativer Text für die Laufzeitangabe"))
 
+    allow_empty_runtime = False
+
     class Meta:
         abstract = True
 
     def clean(self):
-        if not (self.from_year_value or self.until_year_value):
+        if not self.allow_empty_runtime and not (self.from_year_value or self.until_year_value):
             raise ValidationError(_('Please enter either a from or an until date year.'))
 
         # Update from/sort date fields