fix sqlmigrate with idempotent mode

CHANGES.md

@@ -4,6 +4,7 @@
   - changed `ADD COLUMN DEFAULT NULL` to safe operation for code default
   - changed `ADD COLUMN DEFAULT NOT NULL` to safe operation for `db_default` in django 5.0+
   - added `ZERO_DOWNTIME_MIGRATIONS_KEEP_DEFAULT` settings and changed `ADD COLUMN DEFAULT NOT NULL` with this settings to safe operation for django<5.0
+  - fixed sqlmigrate in idempotent mode
   - updated unsafe migrations links to documentation
   - updated patched code to latest django version
   - improved README

django_zero_downtime_migrations/backends/postgres/schema.py

@@ -495,7 +495,11 @@ def __init__(self, connection, collect_sql=False, atomic=True):
             settings, "ZERO_DOWNTIME_MIGRATIONS_FLEXIBLE_STATEMENT_TIMEOUT", False)
         self.RAISE_FOR_UNSAFE = getattr(settings, "ZERO_DOWNTIME_MIGRATIONS_RAISE_FOR_UNSAFE", False)
         self.DEFERRED_SQL = getattr(settings, "ZERO_DOWNTIME_MIGRATIONS_DEFERRED_SQL", True)
-        self.IDEMPOTENT_SQL = getattr(settings, "ZERO_DOWNTIME_MIGRATIONS_IDEMPOTENT_SQL", False)
+        self.IDEMPOTENT_SQL = (
+            getattr(settings, "ZERO_DOWNTIME_MIGRATIONS_IDEMPOTENT_SQL", False)
+            if not collect_sql else
+            False  # disable idempotent mode for sqlmigrate
+        )
         self.KEEP_DEFAULT = getattr(settings, "ZERO_DOWNTIME_MIGRATIONS_KEEP_DEFAULT", False)
         if django.VERSION[:2] >= (5, 0) and hasattr(settings, 'ZERO_DOWNTIME_MIGRATIONS_KEEP_DEFAULT'):
             warnings.warn(

tests/integration/test_migrations.py

@@ -1,4 +1,7 @@
+import os
+
 import django
+from django.apps import apps
 from django.conf import settings
 from django.core.management import call_command
 from django.db import connection
@@ -16,6 +19,17 @@
 )
 
 
+@pytest.mark.django_db(transaction=True)
+@modify_settings(INSTALLED_APPS={"append": "tests.apps.good_flow_app"})
+@override_settings(ZERO_DOWNTIME_MIGRATIONS_RAISE_FOR_UNSAFE=True,
+                   ZERO_DOWNTIME_MIGRATIONS_IDEMPOTENT_SQL=True)
+def test_sqlmigrate_with_idempotent_mode():
+    app_config = apps.get_app_config("good_flow_app")
+    for migration in os.listdir(os.path.join(app_config.path, "migrations")):
+        if not migration.startswith("_") and migration.endswith(".py"):
+            call_command("sqlmigrate", "good_flow_app", migration[:4])
+
+
 @pytest.mark.django_db(transaction=True)
 @modify_settings(INSTALLED_APPS={"append": "tests.apps.good_flow_alter_table_with_same_db_table"})
 @override_settings(ZERO_DOWNTIME_MIGRATIONS_RAISE_FOR_UNSAFE=True)