Fix grouped choices as dict

django_filters/filters.py

@@ -30,6 +30,14 @@
 )
 from .utils import get_model_field, label_for_filter
 
+try:
+    from django.utils.choices import BaseChoiceIterator, normalize_choices
+except ImportError:
+    DJANGO_50 = False
+else:
+    DJANGO_50 = True
+
+
 __all__ = [
     "AllValuesFilter",
     "AllValuesMultipleFilter",
@@ -479,6 +487,12 @@ def __init__(self, choices=None, filters=None, *args, **kwargs):
         if filters is not None:
             self.filters = filters
 
+        if isinstance(self.choices, dict):
+            if DJANGO_50:
+                self.choices = normalize_choices(self.choices)
+            else:
+                assert not DJANGO_50, "Django 5.0 or later is required for dict choices"
+
         all_choices = list(
             chain.from_iterable(
                 [subchoice[0] for subchoice in choice[1]]

tests/test_filters.py

@@ -1105,6 +1105,11 @@ def test_choices_with_optgroups_dont_mistmatch(self):
             choices=[("group", ("a", "a")), ("b", "b")], filters={"a": None, "b": None}
         )
 
+    def test_grouped_choices_as_dictionary(self):
+        DateRangeFilter(
+            choices={"group": {"a": "a", "b": "b"}}, filters={"a": None, "b": None}
+        )
+
     def test_filtering_for_this_year(self):
         qs = mock.Mock(spec=["filter"])
         with mock.patch("django_filters.filters.now") as mock_now: