Refs #27236 -- Added generic mechanism to handle the deprecation of migration operations.

3 files changed, 137 insertions, 14 deletions

diff --git a/tests/check_framework/test_migrations.py b/tests/check_framework/test_migrations.py
new file mode 100644
index 0000000000..0b00690e77
--- /dev/null
+++ b/tests/check_framework/test_migrations.py
@@ -0,0 +1,101 @@
+from django.core import checks
+from django.db import migrations
+from django.db.migrations.operations.base import Operation
+from django.test import TestCase
+
+
+class DeprecatedMigrationOperationTests(TestCase):
+    def test_default_operation(self):
+        class MyOperation(Operation):
+            system_check_deprecated_details = {}
+
+        my_operation = MyOperation()
+
+        class Migration(migrations.Migration):
+            operations = [my_operation]
+
+        self.assertEqual(
+            Migration("name", "app_label").check(),
+            [
+                checks.Warning(
+                    msg="MyOperation has been deprecated.",
+                    obj=my_operation,
+                    id="migrations.WXXX",
+                )
+            ],
+        )
+
+    def test_user_specified_details(self):
+        class MyOperation(Operation):
+            system_check_deprecated_details = {
+                "msg": "This operation is deprecated and will be removed soon.",
+                "hint": "Use something else.",
+                "id": "migrations.W999",
+            }
+
+        my_operation = MyOperation()
+
+        class Migration(migrations.Migration):
+            operations = [my_operation]
+
+        self.assertEqual(
+            Migration("name", "app_label").check(),
+            [
+                checks.Warning(
+                    msg="This operation is deprecated and will be removed soon.",
+                    obj=my_operation,
+                    hint="Use something else.",
+                    id="migrations.W999",
+                )
+            ],
+        )
+
+
+class RemovedMigrationOperationTests(TestCase):
+    def test_default_operation(self):
+        class MyOperation(Operation):
+            system_check_removed_details = {}
+
+        my_operation = MyOperation()
+
+        class Migration(migrations.Migration):
+            operations = [my_operation]
+
+        self.assertEqual(
+            Migration("name", "app_label").check(),
+            [
+                checks.Error(
+                    msg=(
+                        "MyOperation has been removed except for support in historical "
+                        "migrations."
+                    ),
+                    obj=my_operation,
+                    id="migrations.EXXX",
+                )
+            ],
+        )
+
+    def test_user_specified_details(self):
+        class MyOperation(Operation):
+            system_check_removed_details = {
+                "msg": "Support for this operation is gone.",
+                "hint": "Use something else.",
+                "id": "migrations.E999",
+            }
+
+        my_operation = MyOperation()
+
+        class Migration(migrations.Migration):
+            operations = [my_operation]
+
+        self.assertEqual(
+            Migration("name", "app_label").check(),
+            [
+                checks.Error(
+                    msg="Support for this operation is gone.",
+                    obj=my_operation,
+                    hint="Use something else.",
+                    id="migrations.E999",
+                )
+            ],
+        )
diff --git a/tests/db_functions/migrations/0001_setup_extensions.py b/tests/db_functions/migrations/0001_setup_extensions.py
index 0289055499..5909a96eb8 100644
--- a/tests/db_functions/migrations/0001_setup_extensions.py
+++ b/tests/db_functions/migrations/0001_setup_extensions.py
@@ -1,11 +1,22 @@
-from unittest import mock
-
 from django.db import migrations
+from django.db.migrations.operations.base import Operation
+
+
+class DummyOperation(Operation):
+    def state_forwards(self, app_label, state):
+        pass
+
+    def database_forwards(self, app_label, schema_editor, from_state, to_state):
+        pass
+
+    def database_backwards(self, app_label, schema_editor, from_state, to_state):
+        pass
+
 
 try:
     from django.contrib.postgres.operations import CryptoExtension
 except ImportError:
-    CryptoExtension = mock.Mock()
+    CryptoExtension = DummyOperation
 
 
 class Migration(migrations.Migration):
diff --git a/tests/postgres_tests/migrations/0001_setup_extensions.py b/tests/postgres_tests/migrations/0001_setup_extensions.py
index 090abf9649..3edeff7b82 100644
--- a/tests/postgres_tests/migrations/0001_setup_extensions.py
+++ b/tests/postgres_tests/migrations/0001_setup_extensions.py
@@ -1,6 +1,17 @@
-from unittest import mock
-
 from django.db import connection, migrations
+from django.db.migrations.operations.base import Operation
+
+
+class DummyOperation(Operation):
+    def state_forwards(self, app_label, state):
+        pass
+
+    def database_forwards(self, app_label, schema_editor, from_state, to_state):
+        pass
+
+    def database_backwards(self, app_label, schema_editor, from_state, to_state):
+        pass
+
 
 try:
     from django.contrib.postgres.operations import (
@@ -15,14 +26,14 @@ try:
         UnaccentExtension,
     )
 except ImportError:
-    BloomExtension = mock.Mock()
-    BtreeGinExtension = mock.Mock()
-    BtreeGistExtension = mock.Mock()
-    CITextExtension = mock.Mock()
-    CreateExtension = mock.Mock()
-    HStoreExtension = mock.Mock()
-    TrigramExtension = mock.Mock()
-    UnaccentExtension = mock.Mock()
+    BloomExtension = DummyOperation
+    BtreeGinExtension = DummyOperation
+    BtreeGistExtension = DummyOperation
+    CITextExtension = DummyOperation
+    CreateExtension = DummyOperation
+    HStoreExtension = DummyOperation
+    TrigramExtension = DummyOperation
+    UnaccentExtension = DummyOperation
     needs_crypto_extension = False
 else:
     needs_crypto_extension = (
@@ -41,7 +52,7 @@ class Migration(migrations.Migration):
         # dash in its name.
         CreateExtension("uuid-ossp"),
         # CryptoExtension is required for RandomUUID() on PostgreSQL < 13.
-        CryptoExtension() if needs_crypto_extension else mock.Mock(),
+        CryptoExtension() if needs_crypto_extension else DummyOperation(),
         HStoreExtension(),
         TrigramExtension(),
         UnaccentExtension(),