Allow choices to contains optgroups in DateRangeFilter (#1621)

django_filters/filters.py

@@ -1,5 +1,6 @@
 from collections import OrderedDict
 from datetime import timedelta
+from itertools import chain
 
 from django import forms
 from django.core.validators import MaxValueValidator
@@ -478,7 +479,15 @@ def __init__(self, choices=None, filters=None, *args, **kwargs):
         if filters is not None:
             self.filters = filters
 
-        unique = set([x[0] for x in self.choices]) ^ set(self.filters)
+        all_choices = list(
+            chain.from_iterable(
+                [subchoice[0] for subchoice in choice[1]]
+                if isinstance(choice[1], (list, tuple))  # This is an optgroup
+                else [choice[0]]
+                for choice in self.choices
+            )
+        )
+        unique = set(all_choices) ^ set(self.filters)
         assert not unique, (
             "Keys must be present in both 'choices' and 'filters'. Missing keys: "
             "'%s'" % ", ".join(sorted(unique))

tests/test_filters.py

@@ -1100,6 +1100,11 @@ def test_choices_and_filters_mismatch(self):
         with self.assertRaisesMessage(AssertionError, msg):
             DateRangeFilter(choices=[("a", "a")], filters={"b": None})
 
+    def test_choices_with_optgroups_dont_mistmatch(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: