US #675: Define on delete action

taiga/projects/userstories/migrations/0005_auto_20141009_1656.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('userstories', '0004_auto_20141001_1817'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='userstory',
+            name='generated_from_issue',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.SET_NULL, blank=True, to='issues.Issue', verbose_name='generated from issue', related_name='generated_user_stories', null=True),
+        ),
+    ]

taiga/projects/userstories/models.py

@@ -94,6 +94,7 @@ class UserStory(OCCModelMixin, WatchedModelMixin, BlockedMixin, TaggedMixin, mod
                                            verbose_name=_("is team requirement"))
     attachments = generic.GenericRelation("attachments.Attachment")
     generated_from_issue = models.ForeignKey("issues.Issue", null=True, blank=True,
+                                             on_delete=models.SET_NULL,
                                              related_name="generated_user_stories",
                                              verbose_name=_("generated from issue"))
     _importing = None