polls/validators//models: add validation that only vote can be create…

…d per choice per user

apps/polls/models.py

@@ -5,6 +5,7 @@
 from adhocracy4.comments import models as comment_models
 from adhocracy4.models.base import UserGeneratedContentModel
 from adhocracy4.modules import models as module_models
+from apps.polls.validators import single_vote_per_user
 
 
 class QuestionQuerySet(models.QuerySet):
@@ -99,6 +100,16 @@ class Vote(UserGeneratedContentModel):
         related_name='votes'
     )
 
+    def save(self, *args, **kwargs):
+        self.validate_unique()
+        return super().save(*args, **kwargs)
+
+    def validate_unique(self, exclude=None):
+        super(Vote, self).validate_unique(exclude)
+        single_vote_per_user(self.creator,
+                             self.choice,
+                             self.pk)
+
     # Make Vote instances behave like items for rule checking
     @property
     def module(self):

apps/polls/validators.py

@@ -21,21 +21,17 @@ def single_item_per_module(module, model, pk=None):
 def single_vote_per_user(user, choice, pk=None):
     from .models import Vote  # avoid circular import
 
-    if choice.question.multiple_choice:
-        # Allow multiple votes per user for multiple choice questions.
-        return
-
     qs = Vote.objects\
-        .filter(choice__question=choice.question)\
-        .filter(creator=user)
+        .filter(choice=choice,
+                creator=user)
 
     if pk:
         qs = qs.exclude(pk=pk)
 
     if qs.exists():
         raise ValidationError({
             NON_FIELD_ERRORS: [
-                _('Only one vote per question is allowed per user.'),
+                _('Only one vote per choice is allowed per user.'),
             ]
         })