From 69ce0cafa153e515dfc18c5318e8a71360d939fd Mon Sep 17 00:00:00 2001
From: Waket Zheng <waketzheng@gmail.com>
Date: Wed, 18 Dec 2024 00:13:19 +0800
Subject: [PATCH] fix: intermediate table for m2m relation not created (#394)

* fix: intermediate table for m2m relation not created

* Add unittest

* docs: update changelog
---
 CHANGELOG.md                 |  1 +
 aerich/migrate.py            |  6 +++---
 tests/test_sqlite_migrate.py | 31 +++++++++++++++++++++++++++++++
 3 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 85e5e65..5029231 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 ### [0.8.1](Unreleased)
 
 #### Fixed
+- fix: intermediate table for m2m relation not created. (#394)
 - Migrate add m2m field with custom through generate duplicated table. (#393)
 - Migrate drop the wrong m2m field when model have multi m2m fields. (#376)
 - KeyError raised when removing or renaming an existing model (#386)
diff --git a/aerich/migrate.py b/aerich/migrate.py
index 11d7b03..a24b72f 100644
--- a/aerich/migrate.py
+++ b/aerich/migrate.py
@@ -237,8 +237,8 @@ class Migrate:
     def _handle_m2m_fields(
         cls, old_model_describe: Dict, new_model_describe: Dict, model, new_models, upgrade=True
     ) -> None:
-        old_m2m_fields = cast(List[dict], old_model_describe.get("m2m_fields"))
-        new_m2m_fields = cast(List[dict], new_model_describe.get("m2m_fields"))
+        old_m2m_fields = cast(List[dict], old_model_describe.get("m2m_fields", []))
+        new_m2m_fields = cast(List[dict], new_model_describe.get("m2m_fields", []))
         new_tables: Dict[str, dict] = {field["table"]: field for field in new_models.values()}
         for action, option, change in get_dict_diff_by_key(old_m2m_fields, new_m2m_fields):
             if (option and option[-1] == "nullable") or change[0][0] == "db_constraint":
@@ -298,10 +298,10 @@ class Migrate:
 
         for new_model_str, new_model_describe in new_models.items():
             model = cls._get_model(new_model_describe["name"].split(".")[1])
-
             if new_model_str not in old_models:
                 if upgrade:
                     cls._add_operator(cls.add_model(model), upgrade)
+                    cls._handle_m2m_fields({}, new_model_describe, model, new_models, upgrade)
                 else:
                     # we can't find origin model when downgrade, so skip
                     pass
diff --git a/tests/test_sqlite_migrate.py b/tests/test_sqlite_migrate.py
index 9f525eb..01b9582 100644
--- a/tests/test_sqlite_migrate.py
+++ b/tests/test_sqlite_migrate.py
@@ -142,6 +142,16 @@ async def test_m2m_with_custom_through() -> None:
     await foo.groups.add(group)
     foo_group = await FooGroup.get(foo=foo, group=group)
     assert not foo_group.is_active
+
+
+@pytest.mark.asyncio
+async def test_add_m2m_field_after_init_db() -> None:
+    from models import Group
+    name = "5_" + uuid.uuid4().hex
+    foo = await Foo.create(name=name)
+    group = await Group.create(name=name+"1")
+    await foo.groups.add(group)
+    assert (await group.users.all().first()) == foo
 """
 
 
@@ -271,3 +281,24 @@ class FooGroup(Model):
         assert "foo_group" in migration_file_1.read_text()
         r = run_shell("pytest _test.py::test_m2m_with_custom_through")
         assert r.returncode == 0
+
+        # add m2m field after init-db
+        new = """
+    groups = fields.ManyToManyField("models.Group", through="foo_group", related_name="users")
+
+class Group(Model):
+    name = fields.CharField(max_length=60)
+        """
+        if db_file.exists():
+            db_file.unlink()
+        if migrations_dir.exists():
+            shutil.rmtree(migrations_dir)
+        models_py.write_text(MODELS)
+        run_aerich("aerich init-db")
+        models_py.write_text(MODELS + new)
+        run_aerich("aerich migrate")
+        run_aerich("aerich upgrade")
+        migration_file_1 = list(migrations_dir.glob("1_*.py"))[0]
+        assert "foo_group" in migration_file_1.read_text()
+        r = run_shell("pytest _test.py::test_add_m2m_field_after_init_db")
+        assert r.returncode == 0