Yii 2 getOldAttribute() method not working in afterSave - activerecord

Question

I have a model and I want to take an old the value of that model's field after save, I was using getOldAttribute() method and it always returns the latest value?
Code sample
class User extends ActiveRecord
{
public function fields()
{
return [
'id',
'name',
'email' //old value: example#example.com
];
}
}
class UserService extends BaseService
{
/**
* Current user have email is `test#test.com`
*/
public function update(User $user)
{
//before save
$oldEmailBeforSave = $user->getOldAttribute('email'); //work fine and value is `example#example.com`
//handle update user
$this->saveEntity($user)
//after save
$oldEmailAfterSave = $user->getOldAttribute('email'); //not work and value is `test#test.com`
}
}

Answer 1

According to the docs you can use the second parameter of the afterSave( $insert, $changedAttributes) which holds the old values of the attributes that were changed and were saved.
Your code should look like below if you want to get the email fields old value if it was changed
public function afterSave( $insert, $changedAttributes ){
parent::afterSave();
if(!$insert){
$oldEmail = $changedAttributes['email'];
//do something here with the old email value
}
}

Answer 2

When you save new attribute, it is no longer "old". getOldAttribute() represents state from database and allows you to compare whether and how attribute was changed between find() and save(). After calling save(), old attributes are refreshed, so getOldAttribute() will return the same as getAttribute().
If you want to access old state of object, you need to clone it and use these methods on clone - $cloned will represent state of object before calling save():
public function update(User $user)
{
//before save
$oldEmailBeforSave = $user->getOldAttribute('email'); // `example#example.com`
$cloned = clone $user;
//handle update user
$this->saveEntity($user)
//after save
$oldEmailAfterSave = $user->getOldAttribute('email'); // `test#test.com`
$oldEmailAfterSave = $cloned->getOldAttribute('email'); // `example#example.com`
}