From 1213ef2b182261ee690eba484ac7a929ff4707c9 Mon Sep 17 00:00:00 2001
From: Tim Graham <timograham@gmail.com>
Date: Sat, 18 Jun 2016 10:33:37 -0400
Subject: [PATCH] [1.10.x] Refs #15667 -- Fixed crash when indexing
 RadioFieldRenderer with ModelChoiceIterator.

Regression in 86573861a95e5a47dc7ff906443117d75b73dca1
---
 django/forms/widgets.py    | 2 +-
 tests/model_forms/tests.py | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/django/forms/widgets.py b/django/forms/widgets.py
index ab9794a1e78..604a6a401a0 100644
--- a/django/forms/widgets.py
+++ b/django/forms/widgets.py
@@ -693,7 +693,7 @@ class ChoiceFieldRenderer(object):
         self.choices = choices
 
     def __getitem__(self, idx):
-        choice = self.choices[idx]  # Let the IndexError propagate
+        choice = list(self.choices)[idx]  # Let the IndexError propagate
         return self.choice_input_class(self.name, self.value, self.attrs.copy(), choice, idx)
 
     def __str__(self):
diff --git a/tests/model_forms/tests.py b/tests/model_forms/tests.py
index 37ae5089ae4..29472359c26 100644
--- a/tests/model_forms/tests.py
+++ b/tests/model_forms/tests.py
@@ -1573,6 +1573,13 @@ class ModelChoiceFieldTests(TestCase):
         with self.assertNumQueries(1):
             template.render(Context({'field': field}))
 
+    def test_modelchoicefield_index_renderer(self):
+        field = forms.ModelChoiceField(Category.objects.all(), widget=forms.RadioSelect)
+        self.assertEqual(
+            str(field.widget.get_renderer('foo', [])[0]),
+            '<label><input name="foo" type="radio" value="" /> ---------</label>'
+        )
+
 
 class ModelMultipleChoiceFieldTests(TestCase):
     def setUp(self):