fix: mysql drop unique index migrate error

aerich/ddl/mysql/__init__.py

@@ -1,7 +1,12 @@
+from typing import TYPE_CHECKING, List, Type
+
 from tortoise.backends.mysql.schema_generator import MySQLSchemaGenerator
 
 from aerich.ddl import BaseDDL
 
+if TYPE_CHECKING:
+    from tortoise import Model  # noqa:F401
+
 
 class MysqlDDL(BaseDDL):
     schema_generator_cls = MySQLSchemaGenerator
@@ -30,3 +35,29 @@ class MysqlDDL(BaseDDL):
     )
     _MODIFY_COLUMN_TEMPLATE = "ALTER TABLE `{table_name}` MODIFY COLUMN {column}"
     _RENAME_TABLE_TEMPLATE = "ALTER TABLE `{old_table_name}` RENAME TO `{new_table_name}`"
+
+    def _index_name(self, unique: bool, model: "Type[Model]", field_names: List[str]) -> str:
+        if unique:
+            if len(field_names) == 1:
+                # Example: `email = CharField(max_length=50, unique=True)`
+                # Generate schema: `"email" VARCHAR(10) NOT NULL UNIQUE`
+                # Unique index key is the same as field name: `email`
+                return field_names[0]
+            index_prefix = "uid"
+        else:
+            index_prefix = "idx"
+        return self.schema_generator._generate_index_name(index_prefix, model, field_names)
+
+    def add_index(self, model: "Type[Model]", field_names: List[str], unique=False) -> str:
+        return self._ADD_INDEX_TEMPLATE.format(
+            unique="UNIQUE " if unique else "",
+            index_name=self._index_name(unique, model, field_names),
+            table_name=model._meta.db_table,
+            column_names=", ".join(self.schema_generator.quote(f) for f in field_names),
+        )
+
+    def drop_index(self, model: "Type[Model]", field_names: List[str], unique=False) -> str:
+        return self._DROP_INDEX_TEMPLATE.format(
+            index_name=self._index_name(unique, model, field_names),
+            table_name=model._meta.db_table,
+        )

aerich/migrate.py

@@ -477,12 +477,13 @@ def diff_models(cls, old_models: Dict[str, dict], new_models: Dict[str, dict], u
                         _, option, old_new = change
                         if option == "indexed":
                             # change index
-                            unique = new_data_field.get("unique")
                             if old_new[0] is False and old_new[1] is True:
+                                unique = new_data_field.get("unique")
                                 cls._add_operator(
                                     cls._add_index(model, (field_name,), unique), upgrade, True
                                 )
                             else:
+                                unique = old_data_field.get("unique")
                                 cls._add_operator(
                                     cls._drop_index(model, (field_name,), unique), upgrade, True
                                 )

tests/test_ddl.py

@@ -151,9 +151,7 @@ def test_add_index():
     index_u = Migrate.ddl.add_index(Category, ["name"], True)
     if isinstance(Migrate.ddl, MysqlDDL):
         assert index == "ALTER TABLE `category` ADD INDEX `idx_category_name_8b0cb9` (`name`)"
-        assert (
-            index_u == "ALTER TABLE `category` ADD UNIQUE INDEX `uid_category_name_8b0cb9` (`name`)"
-        )
+        assert index_u == "ALTER TABLE `category` ADD UNIQUE INDEX `name` (`name`)"
     elif isinstance(Migrate.ddl, PostgresDDL):
         assert index == 'CREATE INDEX "idx_category_name_8b0cb9" ON "category" ("name")'
         assert index_u == 'CREATE UNIQUE INDEX "uid_category_name_8b0cb9" ON "category" ("name")'
@@ -169,7 +167,7 @@ def test_drop_index():
     ret_u = Migrate.ddl.drop_index(Category, ["name"], True)
     if isinstance(Migrate.ddl, MysqlDDL):
         assert ret == "ALTER TABLE `category` DROP INDEX `idx_category_name_8b0cb9`"
-        assert ret_u == "ALTER TABLE `category` DROP INDEX `uid_category_name_8b0cb9`"
+        assert ret_u == "ALTER TABLE `category` DROP INDEX `name`"
     elif isinstance(Migrate.ddl, PostgresDDL):
         assert ret == 'DROP INDEX "idx_category_name_8b0cb9"'
         assert ret_u == 'DROP INDEX "uid_category_name_8b0cb9"'

tests/test_migrate.py

@@ -44,8 +44,8 @@
                 "python_type": "str",
                 "generated": False,
                 "nullable": False,
-                "unique": False,
-                "indexed": False,
+                "unique": True,
+                "indexed": True,
                 "default": None,
                 "description": None,
                 "docstring": None,
@@ -786,7 +786,8 @@ def test_migrate(mocker: MockerFixture):
     - drop field: User.avatar
     - add index: Email.email
     - add many to many: Email.users
-    - remove unique: User.username
+    - remove unique: Category.slug
+    - add unique: User.username
     - change column: length User.password
     - add unique_together: (name,type) of Product
     - alter default: Config.status
@@ -806,6 +807,7 @@ def test_migrate(mocker: MockerFixture):
     Migrate._merge_operators()
     if isinstance(Migrate.ddl, MysqlDDL):
         expected_upgrade_operators = {
+            "ALTER TABLE `category` DROP INDEX `slug`",
             "ALTER TABLE `category` MODIFY COLUMN `name` VARCHAR(200)",
             "ALTER TABLE `category` MODIFY COLUMN `slug` VARCHAR(100) NOT NULL",
             "ALTER TABLE `config` ADD `user_id` INT NOT NULL  COMMENT 'User'",
@@ -830,14 +832,15 @@ def test_migrate(mocker: MockerFixture):
             "ALTER TABLE `user` MODIFY COLUMN `is_active` BOOL NOT NULL  COMMENT 'Is Active' DEFAULT 1",
             "ALTER TABLE `user` MODIFY COLUMN `is_superuser` BOOL NOT NULL  COMMENT 'Is SuperUser' DEFAULT 0",
             "ALTER TABLE `user` MODIFY COLUMN `longitude` DECIMAL(10,8) NOT NULL",
-            "ALTER TABLE `user` ADD UNIQUE INDEX `uid_user_usernam_9987ab` (`username`)",
+            "ALTER TABLE `user` ADD UNIQUE INDEX `username` (`username`)",
             "CREATE TABLE `email_user` (\n    `email_id` INT NOT NULL REFERENCES `email` (`email_id`) ON DELETE CASCADE,\n    `user_id` INT NOT NULL REFERENCES `user` (`id`) ON DELETE CASCADE\n) CHARACTER SET utf8mb4",
             "CREATE TABLE IF NOT EXISTS `newmodel` (\n    `id` INT NOT NULL PRIMARY KEY AUTO_INCREMENT,\n    `name` VARCHAR(50) NOT NULL\n) CHARACTER SET utf8mb4",
             "ALTER TABLE `category` MODIFY COLUMN `created_at` DATETIME(6) NOT NULL  DEFAULT CURRENT_TIMESTAMP(6)",
             "ALTER TABLE `product` MODIFY COLUMN `body` LONGTEXT NOT NULL",
             "ALTER TABLE `email` MODIFY COLUMN `is_primary` BOOL NOT NULL  DEFAULT 0",
         }
         expected_downgrade_operators = {
+            "ALTER TABLE `category` ADD UNIQUE INDEX `slug` (`slug`)",
             "ALTER TABLE `category` MODIFY COLUMN `name` VARCHAR(200) NOT NULL",
             "ALTER TABLE `category` MODIFY COLUMN `slug` VARCHAR(200) NOT NULL",
             "ALTER TABLE `config` DROP COLUMN `user_id`",
@@ -853,7 +856,7 @@ def test_migrate(mocker: MockerFixture):
             "ALTER TABLE `product` DROP INDEX `uid_product_name_869427`",
             "ALTER TABLE `product` ALTER COLUMN `view_num` DROP DEFAULT",
             "ALTER TABLE `user` ADD `avatar` VARCHAR(200) NOT NULL  DEFAULT ''",
-            "ALTER TABLE `user` DROP INDEX `idx_user_usernam_9987ab`",
+            "ALTER TABLE `user` DROP INDEX `username`",
             "ALTER TABLE `user` MODIFY COLUMN `password` VARCHAR(200) NOT NULL",
             "DROP TABLE IF EXISTS `email_user`",
             "DROP TABLE IF EXISTS `newmodel`",
@@ -877,6 +880,7 @@ def test_migrate(mocker: MockerFixture):
 
     elif isinstance(Migrate.ddl, PostgresDDL):
         expected_upgrade_operators = {
+            'DROP INDEX "uid_category_slug_e9bcff"',
             'ALTER TABLE "category" ALTER COLUMN "name" DROP NOT NULL',
             'ALTER TABLE "category" ALTER COLUMN "slug" TYPE VARCHAR(100) USING "slug"::VARCHAR(100)',
             'ALTER TABLE "category" ALTER COLUMN "created_at" TYPE TIMESTAMPTZ USING "created_at"::TIMESTAMPTZ',
@@ -909,6 +913,7 @@ def test_migrate(mocker: MockerFixture):
             'CREATE UNIQUE INDEX "uid_user_usernam_9987ab" ON "user" ("username")',
         }
         expected_downgrade_operators = {
+            'CREATE UNIQUE INDEX "uid_category_slug_e9bcff" ON "category" ("slug")',
             'ALTER TABLE "category" ALTER COLUMN "name" SET NOT NULL',
             'ALTER TABLE "category" ALTER COLUMN "slug" TYPE VARCHAR(200) USING "slug"::VARCHAR(200)',
             'ALTER TABLE "category" ALTER COLUMN "created_at" TYPE TIMESTAMPTZ USING "created_at"::TIMESTAMPTZ',
@@ -935,7 +940,7 @@ def test_migrate(mocker: MockerFixture):
             'ALTER TABLE "product" ALTER COLUMN "body" TYPE TEXT USING "body"::TEXT',
             'DROP INDEX "idx_product_name_869427"',
             'DROP INDEX "idx_email_email_4a1a33"',
-            'DROP INDEX "idx_user_usernam_9987ab"',
+            'DROP INDEX "uid_user_usernam_9987ab"',
             'DROP INDEX "uid_product_name_869427"',
             'DROP TABLE IF EXISTS "email_user"',
             'DROP TABLE IF EXISTS "newmodel"',