Gorm Create duplicate index when AutoMigrate table schema

GORM Playground Link

https://github.com/go-gorm/playground/pull/1

Description

reproduce

package main

import (
    "gorm.io/driver/mysql"
    "gorm.io/gorm"
)

type User struct {
    gorm.Model
    Code string `gorm:"unique;comment:my code;"`
}

type User2 struct {
    gorm.Model
    Code string `gorm:"unique;comment:my code2;default:hello"`
}

func main() {
    dsn := "root:@tcp(127.0.0.1:3306)/test?charset=utf8mb4&parseTime=True&loc=Local"
    db, err := gorm.Open(mysql.Open(dsn), &gorm.Config{})
    mustBeNil(err)

    db.Migrator().DropTable(&User{})
    err = db.AutoMigrate(&User{})
    mustBeNil(err)

    err = db.Table("users").AutoMigrate(&User2{})
    mustBeNil(err)
}

func mustBeNil(err error) {
    if err != nil {
        panic(err)
    }
}

After running this code, the final table schema will be:

***************************[ 1. row ]***************************
Table        | users
Create Table | CREATE TABLE `users` (
  `id` bigint unsigned NOT NULL AUTO_INCREMENT,
  `created_at` datetime(3) DEFAULT NULL,
  `updated_at` datetime(3) DEFAULT NULL,
  `deleted_at` datetime(3) DEFAULT NULL,
  `code` varchar(191) DEFAULT 'hello' COMMENT 'my code2',
  PRIMARY KEY (`id`),
  UNIQUE KEY `code` (`code`),
  UNIQUE KEY `code_2` (`code`),
  KEY `idx_users_deleted_at` (`deleted_at`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci

As you can see, there are 2 same unique index on the column code. I expected only 1 unique index on column code.

Comment From: github-actions[bot]

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