[5.1.x] Fixed #35638 -- Updated validate_constraints to consider db_default.

Backport of 509763c79952cde02d9f5b584af4278bdbed77b2 from main.

3 files changed, 11 insertions, 2 deletions

diff --git a/tests/postgres_tests/migrations/0002_create_test_models.py b/tests/postgres_tests/migrations/0002_create_test_models.py
index 5538b436ad..188f79607d 100644
--- a/tests/postgres_tests/migrations/0002_create_test_models.py
+++ b/tests/postgres_tests/migrations/0002_create_test_models.py
@@ -434,7 +434,7 @@ class Migration(migrations.Migration):
                         primary_key=True,
                     ),
                 ),
-                ("ints", IntegerRangeField(null=True, blank=True)),
+                ("ints", IntegerRangeField(null=True, blank=True, db_default=(5, 10))),
                 ("bigints", BigIntegerRangeField(null=True, blank=True)),
                 ("decimals", DecimalRangeField(null=True, blank=True)),
                 ("timestamps", DateTimeRangeField(null=True, blank=True)),
diff --git a/tests/postgres_tests/models.py b/tests/postgres_tests/models.py
index a97894e327..e3118bc590 100644
--- a/tests/postgres_tests/models.py
+++ b/tests/postgres_tests/models.py
@@ -130,7 +130,7 @@ class LineSavedSearch(PostgreSQLModel):
 
 
 class RangesModel(PostgreSQLModel):
-    ints = IntegerRangeField(blank=True, null=True)
+    ints = IntegerRangeField(blank=True, null=True, db_default=(5, 10))
     bigints = BigIntegerRangeField(blank=True, null=True)
     decimals = DecimalRangeField(blank=True, null=True)
     timestamps = DateTimeRangeField(blank=True, null=True)
diff --git a/tests/postgres_tests/test_constraints.py b/tests/postgres_tests/test_constraints.py
index 3cc76cdcfe..9a572c9bf2 100644
--- a/tests/postgres_tests/test_constraints.py
+++ b/tests/postgres_tests/test_constraints.py
@@ -1238,3 +1238,12 @@ class ExclusionConstraintTests(PostgreSQLTestCase):
             constraint_name,
             self.get_constraints(ModelWithExclusionConstraint._meta.db_table),
         )
+
+    def test_database_default(self):
+        constraint = ExclusionConstraint(
+            name="ints_equal", expressions=[("ints", RangeOperators.EQUAL)]
+        )
+        RangesModel.objects.create()
+        msg = "Constraint “ints_equal” is violated."
+        with self.assertRaisesMessage(ValidationError, msg):
+            constraint.validate(RangesModel, RangesModel())