[4.1.x] Fixed #34205 -- Fixed Meta.constraints validation crash with ArrayField and __len lookup.

Regression in 88fc9e2826044110b7b22577a227f122fe9c1fb5 that began
manifesting in Django 4.1.

Backport of c5ed884eabf3b2b67581c55bf6c87e721f69157f from main.

1 files changed, 10 insertions, 0 deletions

diff --git a/tests/postgres_tests/test_constraints.py b/tests/postgres_tests/test_constraints.py
index 74c07e4fab..a45aed153d 100644
--- a/tests/postgres_tests/test_constraints.py
+++ b/tests/postgres_tests/test_constraints.py
@@ -67,6 +67,16 @@ class SchemaTests(PostgreSQLTestCase):
             RangesModel.objects.create(ints=(20, 50))
         RangesModel.objects.create(ints=(10, 30))
 
+    def test_check_constraint_array_length(self):
+        constraint = CheckConstraint(
+            check=Q(field__len=1),
+            name="array_length",
+        )
+        msg = f"Constraint “{constraint.name}” is violated."
+        with self.assertRaisesMessage(ValidationError, msg):
+            constraint.validate(IntegerArrayModel, IntegerArrayModel())
+        constraint.validate(IntegerArrayModel, IntegerArrayModel(field=[1]))
+
     def test_check_constraint_daterange_contains(self):
         constraint_name = "dates_contains"
         self.assertNotIn(