[1.6.x] Fixed #21643 -- repeated execution of qs with F() + timedelta

Thanks Tim Graham for review and Tai Lee for the additional test to prove
this was a regression in 1.6.

Backport of 7f2485b4d1 and 8137215973 from master

1 files changed, 14 insertions, 0 deletions

diff --git a/tests/expressions_regress/tests.py b/tests/expressions_regress/tests.py
index ddb2c83b4f..a9737f433d 100644
--- a/tests/expressions_regress/tests.py
+++ b/tests/expressions_regress/tests.py
@@ -259,6 +259,20 @@ class FTimeDeltaTests(TestCase):
         self.days_long.append(e4.completed-e4.assigned)
         self.expnames = [e.name for e in Experiment.objects.all()]
 
+    def test_multiple_query_compilation(self):
+        # Ticket #21643
+        queryset = Experiment.objects.filter(end__lt=F('start') + datetime.timedelta(hours=1))
+        q1 = str(queryset.query)
+        q2 = str(queryset.query)
+        self.assertEqual(q1, q2)
+
+    def test_query_clone(self):
+        # Ticket #21643
+        qs = Experiment.objects.filter(end__lt=F('start') + datetime.timedelta(hours=1))
+        qs2 = qs.all()
+        list(qs)
+        list(qs2)
+
     def test_delta_add(self):
         for i in range(len(self.deltas)):
             delta = self.deltas[i]