From b1ff2418f5d9bb9e964b7274107ce2c7104c65e0 Mon Sep 17 00:00:00 2001
From: ar0ne <camtbitakou@yandex.ru>
Date: Tue, 26 Dec 2023 22:55:51 +0530
Subject: [PATCH] added option to generate empty migration file

---
 aerich/__init__.py    |  4 ++--
 aerich/migrate.py     |  8 ++++++--
 tests/test_migrate.py | 17 ++++++++++++++++-
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/aerich/__init__.py b/aerich/__init__.py
index 3ad1e91..f3e045c 100644
--- a/aerich/__init__.py
+++ b/aerich/__init__.py
@@ -123,8 +123,8 @@ class Command:
         inspect = cls(connection, tables)
         return await inspect.inspect()
 
-    async def migrate(self, name: str = "update"):
-        return await Migrate.migrate(name)
+    async def migrate(self, name: str = "update", empty: bool = False) -> str:
+        return await Migrate.migrate(name, empty)
 
     async def init_db(self, safe: bool):
         location = self.location
diff --git a/aerich/migrate.py b/aerich/migrate.py
index 0d691d5..e5c3cec 100644
--- a/aerich/migrate.py
+++ b/aerich/migrate.py
@@ -130,12 +130,16 @@ class Migrate:
         return version
 
     @classmethod
-    async def migrate(cls, name) -> str:
+    async def migrate(cls, name: str, empty: bool) -> str:
         """
         diff old models and new models to generate diff content
-        :param name:
+        :param name: str name for migration
+        :param empty: bool if True generates empty migration
         :return:
         """
+        if empty:
+            return await cls._generate_diff_py(name)
+
         new_version_content = get_models_describe(cls.app)
         cls.diff_models(cls._last_version_content, new_version_content)
         cls.diff_models(new_version_content, cls._last_version_content, False)
diff --git a/tests/test_migrate.py b/tests/test_migrate.py
index 94353d3..c3cca03 100644
--- a/tests/test_migrate.py
+++ b/tests/test_migrate.py
@@ -1,3 +1,6 @@
+import tempfile
+from pathlib import Path
+
 import pytest
 from pytest_mock import MockerFixture
 
@@ -5,7 +8,7 @@ from aerich.ddl.mysql import MysqlDDL
 from aerich.ddl.postgres import PostgresDDL
 from aerich.ddl.sqlite import SqliteDDL
 from aerich.exceptions import NotSupportError
-from aerich.migrate import Migrate
+from aerich.migrate import MIGRATE_TEMPLATE, Migrate
 from aerich.utils import get_models_describe
 
 old_models_describe = {
@@ -966,3 +969,15 @@ def test_sort_all_version_files(mocker):
         "10_datetime_update.py",
         "11_datetime_update.py",
     ]
+
+async def test_empty_migration(mocker) -> None:
+    mocker.patch("os.listdir", return_value=[])
+    Migrate.app = "foo"
+    expected_content = MIGRATE_TEMPLATE.format(upgrade_sql=";", downgrade_sql=";")
+    with tempfile.TemporaryDirectory() as temp_dir:
+        Migrate.migrate_location = temp_dir
+
+        migration_file = await Migrate.migrate("update", True)
+
+        with open(Path(temp_dir, migration_file), "r") as f:
+            assert f.read() == expected_content