refactor: prepare to decouple the "model migration" package and "models" package (#38533)

Migrations should never use model structs directly, because the model
structs can be different in different releases. e.g. if one migration uses
"User" model, it works in the early releases, then one day, when the
User model changes, the migration breaks because it will use the
new (incorrect) User model, it should only use the old User model.

The same to "modules/structs".

---------

Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: delvh <dev.lh@web.de>

modelmigration/v1_11/v110.go

@@ -0,0 +1,30 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package v1_11
+
+import (
+	"gitea.dev/modelmigration/base"
+
+	"xorm.io/xorm/schemas"
+)
+
+func ChangeReviewContentToText(x base.EngineMigration) error {
+	switch x.Dialect().URI().DBType {
+	case schemas.MYSQL:
+		_, err := x.Exec("ALTER TABLE review MODIFY COLUMN content TEXT")
+		return err
+	case schemas.ORACLE:
+		_, err := x.Exec("ALTER TABLE review MODIFY content TEXT")
+		return err
+	case schemas.MSSQL:
+		_, err := x.Exec("ALTER TABLE review ALTER COLUMN content TEXT")
+		return err
+	case schemas.POSTGRES:
+		_, err := x.Exec("ALTER TABLE review ALTER COLUMN content TYPE TEXT")
+		return err
+	default:
+		// SQLite doesn't support ALTER COLUMN, and it seem to already make String to _TEXT_ default so no migration needed
+		return nil
+	}
+}