Refs #30060, Refs #34217 -- Made SchemaEditor not generate SQL for CheckConstraint if not supported.

The new logic mirrors the logic in SchemaEditor._delete_check_sql()
added in 68ef274bc505cd44f305c03cbf84cf08826200a8.

Thanks Tim Graham for the report.

2 files changed, 24 insertions, 5 deletions

diff --git a/django/db/backends/base/schema.py b/django/db/backends/base/schema.py
index 070211f6d2..db7e4c69c4 100644
--- a/django/db/backends/base/schema.py
+++ b/django/db/backends/base/schema.py
@@ -1726,6 +1726,8 @@ class BaseDatabaseSchemaEditor:
         }
 
     def _create_check_sql(self, model, name, check):
+        if not self.connection.features.supports_table_check_constraints:
+            return None
         return Statement(
             self.sql_create_check,
             table=Table(model._meta.db_table, self.quote_name),
diff --git a/tests/migrations/test_operations.py b/tests/migrations/test_operations.py
index 2f97659046..df12ff428d 100644
--- a/tests/migrations/test_operations.py
+++ b/tests/migrations/test_operations.py
@@ -3555,7 +3555,6 @@ class OperationTests(OperationTestBase):
         self.assertIndexNotExists(table_name, ["pink", "weight"])
         self.assertUniqueConstraintExists(table_name, ["pink", "weight"])
 
-    @skipUnlessDBFeature("supports_table_check_constraints")
     def test_add_constraint(self):
         project_state = self.set_up_test_model("test_addconstraint")
         gt_check = models.Q(pink__gt=2)
@@ -3581,11 +3580,20 @@ class OperationTests(OperationTestBase):
         Pony = new_state.apps.get_model("test_addconstraint", "Pony")
         self.assertEqual(len(Pony._meta.constraints), 1)
         # Test the database alteration
-        with connection.schema_editor() as editor:
+        with (
+            CaptureQueriesContext(connection) as ctx,
+            connection.schema_editor() as editor,
+        ):
             gt_operation.database_forwards(
                 "test_addconstraint", editor, project_state, new_state
             )
-        with self.assertRaises(IntegrityError), transaction.atomic():
+        if connection.features.supports_table_check_constraints:
+            with self.assertRaises(IntegrityError), transaction.atomic():
+                Pony.objects.create(pink=1, weight=1.0)
+        else:
+            self.assertIs(
+                any("CHECK" in query["sql"] for query in ctx.captured_queries), False
+            )
             Pony.objects.create(pink=1, weight=1.0)
         # Add another one.
         lt_check = models.Q(pink__lt=100)
@@ -3600,11 +3608,20 @@ class OperationTests(OperationTestBase):
         )
         Pony = new_state.apps.get_model("test_addconstraint", "Pony")
         self.assertEqual(len(Pony._meta.constraints), 2)
-        with connection.schema_editor() as editor:
+        with (
+            CaptureQueriesContext(connection) as ctx,
+            connection.schema_editor() as editor,
+        ):
             lt_operation.database_forwards(
                 "test_addconstraint", editor, project_state, new_state
             )
-        with self.assertRaises(IntegrityError), transaction.atomic():
+        if connection.features.supports_table_check_constraints:
+            with self.assertRaises(IntegrityError), transaction.atomic():
+                Pony.objects.create(pink=100, weight=1.0)
+        else:
+            self.assertIs(
+                any("CHECK" in query["sql"] for query in ctx.captured_queries), False
+            )
             Pony.objects.create(pink=100, weight=1.0)
         # Test reversal
         with connection.schema_editor() as editor: