Allow same annotation to be used several times by stats

When using the same annotations twice as stats, it does not work. See tests/test_stats/StatsTest/test_animals_annotation_duplicates

binder/views.py

@@ -2985,12 +2985,13 @@ def stats_view(self, request):
 			stats = stats.split(',')
 
 		return JsonResponse({
-			stat: self._get_stat(request, queryset, stat, annotations, include_annotations)
+			stat: self._get_stat(request, queryset, stat, annotations.copy(), include_annotations)
 			for stat in stats
 		})
 
 
 	def _get_stat(self, request, queryset, stat, annotations, include_annotations):
+		# NOTE: uses annotations! If called multiple times, provide a copy
 		# Get stat definition
 		try:
 			stat = self.stats[stat]

tests/test_stats.py

@@ -86,13 +86,25 @@ def test_stat_not_found(self):
 			'debug': ANY(),
 		})
 
-	def test_animals_by_zoo(self):
-		res = self.get_stats('by_zoo')
+	# annotations
+	def test_animals_annotation(self):
+		res = self.get_stats('stat_total_magic_number')
 		self.assertEqual(res, {
-			'by_zoo': {
-				'value': {'Zoo 1': 1, 'Zoo 2': 2},
-				'other': 0,
+			'stat_total_magic_number': {
+				'value': 6,
 				'filters': {},
-				'group_by': 'zoo.name',
 			},
 		})
+
+	def test_animals_annotation_duplicates(self):
+		res = self.get_stats('stat_total_magic_number,stat_total_magic_number_times_hunderd')
+		self.assertEqual(res, {
+			'stat_total_magic_number': {
+				'value': 6,
+				'filters': {},
+			},
+			'stat_total_magic_number_times_hunderd': {
+				'value': 600,
+				'filters': {},
+			}
+		})

tests/testapp/models/animal.py

@@ -35,3 +35,4 @@ class Annotations:
 			Value(request.GET.get('animal_name_prefix', 'Sir') + ' '),
 			F('name'),
 		))
+		magic_number = Value(2)

tests/testapp/views/animal.py

@@ -1,4 +1,4 @@
-from django.db.models import Count, Value
+from django.db.models import Count, Value, Sum
 
 from binder.views import ModelView, Stat
 
@@ -20,4 +20,12 @@ class AnimalView(ModelView):
 			Count(Value(1)),
 			group_by='zoo.name',
 		),
+		'stat_total_magic_number': Stat(
+			Sum('magic_number'),
+			annotations=['magic_number'],
+		),
+		'stat_total_magic_number_times_hunderd': Stat(
+			Sum('magic_number')*100,
+			annotations=['magic_number'],
+		),
 	}