fixes #12, #154 : disabling native json support

django_redshift_backend/base.py

@@ -10,6 +10,7 @@
 import re
 import uuid
 import logging
+import json
 
 import django
 from django.utils import timezone
@@ -53,6 +54,7 @@ class DatabaseFeatures(BasePGDatabaseFeatures):
     supports_column_check_constraints = False
     can_distinct_on_fields = False
     allows_group_by_selected_pks = False
+    has_native_json_field = False  # Redshift doesn't support JSONField.
     has_native_uuid_field = False
     supports_aggregate_filter_clause = False
     supports_combined_alters = False  # since django-1.8
@@ -166,6 +168,10 @@ def prepare_join_on_clause(self, lhs_table, lhs_field, rhs_table, rhs_field):
 
         return lhs_expr, rhs_expr
 
+    # copy from djang 4.2 base/operations.py
+    def adapt_json_value(self, value, encoder):
+        return json.dumps(value, cls=encoder)
+
 
 def _get_type_default(field):
     internal_type = field.get_internal_type()
@@ -1124,6 +1130,9 @@ def remove_field(self, model, field):
 redshift_data_types = {
     "AutoField": "integer identity(1, 1)",
     "BigAutoField": "bigint identity(1, 1)",
+    # Redshift doesn't support JSONField.
+    # https://docs.aws.amazon.com/redshift/latest/dg/federated-data-types.html
+    "JSONField": "varchar",
     "TextField": "varchar(max)",  # text must be varchar(max)
     "UUIDField": "varchar(36)",  # redshift doesn't support uuid fields
     "BinaryField": "varbyte(%(max_length)s)",

tests/test_migrations.py

@@ -583,3 +583,30 @@ def test_foreign_key_to_non_id(self):
             '''ALTER TABLE "test_pony" ADD CONSTRAINT "test_pony_remote_e347b432_uniq" UNIQUE ("remote");''',
             '''ALTER TABLE "test_rider" ADD CONSTRAINT "test_rider_pony_remote_id_269d66d9_fk_test_pony_remote" FOREIGN KEY ("pony_remote_id") REFERENCES "test_pony" ("remote");'''
         ], sqls)
+
+    @postgres_fixture()
+    def test_add_json(self):
+        from django_redshift_backend.base import DatabaseWrapper
+
+        new_state = self.set_up_test_model('test')
+        operations = [
+            migrations.AddField(
+                model_name='Pony',
+                name='structure',
+                field=models.JSONField(
+                    verbose_name='json data',
+                    null=False,
+                    default={"key1": "value", "key2": 1},
+                ),
+            ),
+        ]
+
+        with self.collect_sql() as sqls:
+            self.apply_operations('test', new_state, operations)
+
+        data_type = DatabaseWrapper.data_types['JSONField']
+        default = """DEFAULT '{"key1": "value", "key2": 1}'"""
+
+        self.assertEqual([
+            f'''ALTER TABLE "test_pony" ADD COLUMN "structure" {data_type} {default} NOT NULL;''',
+        ], sqls)