Fix create/drop indexes in every migration (#377)

* Add `__eq__` method for `Index`instances

* tests: add Index test case

* refactor: compare index instances before set hash and eq func to class

* fix: sort fields when generating index hash

* docs: update changlog

* fix style issue

* refactor: use CustomIndex instead of postgres special HashIndex

* Check tortoise version before patch Index

* Add comment

* Add comment for why > work

---------

Co-authored-by: dbf <somnium@riseup.net>

CHANGELOG.md

@@ -16,6 +16,7 @@
 - Fix configuration file reading error when containing Chinese characters. (#286)
 - sqlite: failed to create/drop index. (#302)
 - PostgreSQL: Cannot drop constraint after deleting or rename FK on a model. (#378)
+- Fix create/drop indexes in every migration. (#377)
 - Sort m2m fields before comparing them with diff. (#271)
 
 #### Changed

aerich/migrate.py

@@ -1,4 +1,5 @@
-import hashlib
+from __future__ import annotations
+
 import importlib
 import os
 from datetime import datetime
@@ -6,6 +7,7 @@ from pathlib import Path
 from typing import Dict, Iterable, List, Optional, Set, Tuple, Type, Union, cast
 
 import asyncclick as click
+import tortoise
 from dictdiffer import diff
 from tortoise import BaseDBAsyncClient, Model, Tortoise
 from tortoise.exceptions import OperationalError
@@ -202,21 +204,25 @@ class Migrate:
 
     @classmethod
     def _handle_indexes(cls, model: Type[Model], indexes: List[Union[Tuple[str], Index]]) -> list:
-        ret: list = []
+        if tortoise.__version__ > "0.22.2":
+            # The min version of tortoise is '0.11.0', so we can compare it by a `>`,
+            # tortoise>0.22.2 have __eq__/__hash__ with Index class since 313ee76.
+            return indexes
+        if index_classes := set(index.__class__ for index in indexes if isinstance(index, Index)):
+            # Leave magic patch here to compare with older version of tortoise-orm
+            # TODO: limit tortoise>0.22.2 in pyproject.toml and remove this function when v0.9.0 released
+            for index_cls in index_classes:
+                if index_cls(fields=("id",)) != index_cls(fields=("id",)):
 
-        def index_hash(self) -> str:
-            h = hashlib.new("MD5", usedforsecurity=False)  # type:ignore[call-arg]
-            h.update(
-                self.index_name(cls.ddl.schema_generator, model).encode()
-                + self.__class__.__name__.encode()
-            )
-            return h.hexdigest()
+                    def _hash(self) -> int:
+                        return hash((tuple(sorted(self.fields)), self.name, self.expressions))
 
-        for index in indexes:
-            if isinstance(index, Index):
-                index.__hash__ = index_hash  # type:ignore[method-assign,assignment]
-            ret.append(index)
-        return ret
+                    def _eq(self, other) -> bool:
+                        return type(self) is type(other) and self.__dict__ == other.__dict__
+
+                    setattr(index_cls, "__hash__", _hash)
+                    setattr(index_cls, "__eq__", _eq)
+        return indexes
 
     @classmethod
     def _get_indexes(cls, model, model_describe: dict) -> Set[Union[Index, Tuple[str, ...]]]:

tests/indexes.py

@@ -0,0 +1,7 @@
+from tortoise.indexes import Index
+
+
+class CustomIndex(Index):
+    def __init__(self, *args, **kw) -> None:
+        super().__init__(*args, **kw)
+        self._foo = ""

tests/models.py

@@ -3,6 +3,9 @@ import uuid
 from enum import IntEnum
 
 from tortoise import Model, fields
+from tortoise.indexes import Index
+
+from tests.indexes import CustomIndex
 
 
 class ProductType(IntEnum):
@@ -33,6 +36,10 @@ class User(Model):
 
     products: fields.ManyToManyRelation["Product"]
 
+    class Meta:
+        # reverse indexes elements
+        indexes = [CustomIndex(fields=("is_superuser",)), Index(fields=("username", "is_active"))]
+
 
 class Email(Model):
     email_id = fields.IntField(primary_key=True)

tests/old_models.py

@@ -2,6 +2,9 @@ import datetime
 from enum import IntEnum
 
 from tortoise import Model, fields
+from tortoise.indexes import Index
+
+from tests.indexes import CustomIndex
 
 
 class ProductType(IntEnum):
@@ -31,6 +34,9 @@ class User(Model):
     intro = fields.TextField(default="")
     longitude = fields.DecimalField(max_digits=12, decimal_places=9)
 
+    class Meta:
+        indexes = [Index(fields=("username", "is_active")), CustomIndex(fields=("is_superuser",))]
+
 
 class Email(Model):
     email = fields.CharField(max_length=200)

tests/test_migrate.py

@@ -3,6 +3,7 @@ from pathlib import Path
 import pytest
 import tortoise
 from pytest_mock import MockerFixture
+from tortoise.indexes import Index
 
 from aerich.ddl.mysql import MysqlDDL
 from aerich.ddl.postgres import PostgresDDL
@@ -10,6 +11,7 @@ from aerich.ddl.sqlite import SqliteDDL
 from aerich.exceptions import NotSupportError
 from aerich.migrate import MIGRATE_TEMPLATE, Migrate
 from aerich.utils import get_models_describe
+from tests.indexes import CustomIndex
 
 # tortoise-orm>=0.21 changes IntField constraints
 # from {"ge": 1, "le": 2147483647} to {"ge": -2147483648, "le": 2147483647}
@@ -608,7 +610,7 @@ old_models_describe = {
         "description": None,
         "docstring": None,
         "unique_together": [],
-        "indexes": [],
+        "indexes": [Index(fields=("username", "is_active")), CustomIndex(fields=("is_superuser",))],
         "pk_field": {
             "name": "id",
             "field_type": "IntField",