Add identifier field to questions

src/pretix/base/migrations/0085_auto_20180312_1119.py

@@ -0,0 +1,59 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.11 on 2018-03-12 11:19
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+from django.utils.crypto import get_random_string
+
+
+def set_identifiers(apps, schema_editor):
+    Question = apps.get_model('pretixbase', 'Question')
+    QuestionOption = apps.get_model('pretixbase', 'QuestionOption')
+
+    for q in Question.objects.select_related('event'):
+        if not q.identifier:
+            charset = list('ABCDEFGHJKLMNPQRSTUVWXYZ3789')
+            while True:
+                code = get_random_string(length=8, allowed_chars=charset)
+                if not Question.objects.filter(event=q.event, identifier=code).exists():
+                    q.identifier = code
+                    q.save()
+                    break
+
+    for q in QuestionOption.objects.select_related('question', 'question__event'):
+        if not q.identifier:
+            charset = list('ABCDEFGHJKLMNPQRSTUVWXYZ3789')
+            while True:
+                code = get_random_string(length=8, allowed_chars=charset)
+                if not QuestionOption.objects.filter(question__event=q.question.event, identifier=code).exists():
+                    q.identifier = code
+                    q.save()
+                    break
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0084_questionoption_position'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='question',
+            name='identifier',
+            field=models.CharField(default='', max_length=190),
+            preserve_default=False,
+        ),
+        migrations.AddField(
+            model_name='questionoption',
+            name='identifier',
+            field=models.CharField(default='', max_length=190),
+            preserve_default=False,
+        ),
+        migrations.AlterField(
+            model_name='user',
+            name='locale',
+            field=models.CharField(choices=[('en', 'English'), ('de', 'German'), ('de-informal', 'German (informal)'), ('nl', 'Dutch'), ('da', 'Danish'), ('pt-br', 'Portuguese (Brazil)')], default='en', max_length=50, verbose_name='Language'),
+        ),
+        migrations.RunPython(set_identifiers, migrations.RunPython.noop)
+    ]