Fix default function when migrate

.gitignore

@@ -146,3 +146,4 @@ aerich.ini
 src
 .vscode
 .DS_Store
+.python-version

aerich/ddl/__init__.py

@@ -4,6 +4,8 @@ from typing import List, Type
 from tortoise import BaseDBAsyncClient, Model
 from tortoise.backends.base.schema_generator import BaseSchemaGenerator
 
+from aerich.utils import is_default_function
+
 
 class BaseDDL:
     schema_generator_cls: Type[BaseSchemaGenerator] = BaseSchemaGenerator
@@ -76,7 +78,7 @@ class BaseDDL:
         auto_now_add = field_describe.get("auto_now_add", False)
         auto_now = field_describe.get("auto_now", False)
         if default is not None or auto_now_add:
-            if field_describe.get("field_type") in ["UUIDField", "TextField", "JSONField"]:
+            if field_describe.get("field_type") in ["UUIDField", "TextField", "JSONField"] or is_default_function(default):
                 default = ""
             else:
                 try:

aerich/migrate.py

@@ -1,4 +1,5 @@
 import os
+import re
 from datetime import datetime
 from pathlib import Path
 from typing import Dict, List, Optional, Tuple, Type
@@ -10,7 +11,12 @@ from tortoise.exceptions import OperationalError
 
 from aerich.ddl import BaseDDL
 from aerich.models import MAX_VERSION_LENGTH, Aerich
-from aerich.utils import get_app_connection, get_models_describe, write_version_file
+from aerich.utils import (
+    get_app_connection,
+    get_models_describe,
+    is_default_function,
+    write_version_file,
+)
 
 
 class Migrate:
@@ -394,8 +400,13 @@ class Migrate:
                             # continue since repeated with others
                             continue
                         elif option == "default":
-                            # change column default
-                            cls._add_operator(cls._alter_default(model, new_data_field), upgrade)
+                            if not (
+                                is_default_function(old_new[0]) or is_default_function(old_new[1])
+                            ):
+                                # change column default
+                                cls._add_operator(
+                                    cls._alter_default(model, new_data_field), upgrade
+                                )
                         elif option == "unique":
                             # because indexed include it
                             pass

aerich/utils.py

@@ -1,4 +1,5 @@
 import importlib
+import re
 from typing import Dict
 
 from click import BadOptionUsage, Context
@@ -121,3 +122,7 @@ def get_models_describe(app: str) -> Dict:
         describe = model.describe()
         ret[describe.get("name")] = describe
     return ret
+
+
+def is_default_function(string: str):
+    return re.match(r"^<function.+>$", str(string or ""))

tests/models.py

@@ -1,4 +1,5 @@
 import datetime
+import uuid
 from enum import IntEnum
 
 from tortoise import Model, fields
@@ -38,9 +39,13 @@ class Email(Model):
     users = fields.ManyToManyField("models.User")
 
 
+def default_name():
+    return uuid.uuid4()
+
+
 class Category(Model):
     slug = fields.CharField(max_length=100)
-    name = fields.CharField(max_length=200, null=True)
+    name = fields.CharField(max_length=200, null=True, default=default_name)
     user = fields.ForeignKeyField("models.User", description="User")
     created_at = fields.DatetimeField(auto_now_add=True)