Jam_Model::changed() always returns TRUE after Jam_Model::set() is called

[yanev]

All fields on which the set method has been invoked are marked as changed no matter that the field content hasn't changed at all. Example:
// $post contains an array of fields => values which have same values with
// the values of the model e.g $model->name == $post['name']

$model = Jam::find('model', 1);
$model->set($post);
$model->changed('name'); // returns TRUE, but the expected behavior is FALSE
$model->name !== $post['name'] // returns FALSE which is correct

[hkdobrev]

👍

[ivank]

Its setup this way because "changed" works for associations too, but it would be quite bad for performance to load the old record every time you want to check for a changed model, and fixing it only for fields will make the behavior inconsistent - what do you think about this?

[hkdobrev]

@ivank I remember how the Jam_Model::set() method was working before (perhaps even before having Jam_Validated class). The set method had three parameters: $key, $value and $force.

Every time something called set it compared the new value and the original value of the field unless $force was set to TRUE.

This way only actually changed fields were added to changed.

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fixing it only for fields will make the behavior inconsistent - what do you think about this?

I don't think this should work for associations. IMHO it is OK to be inconsistent in this case if it is well explained in the documentation and the PHPDoc.

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The main issue it will resolve is with model_before_save and model_after_save events in the behaviors. ATM many behaviors check if a field is changed and then update a cache field or something like that. Right now a lot of additional queries are executed when a form is submitted, because the behaviors think a field is changed every time when a form containing the field is submitted.

[hkdobrev]

The Eloquent ORM does not keep the changed (a.k.a. dirty) array of attributes. It is always generating it on the fly.

And every time you read the changed array it checks if the current and original values are different.

Eloquent::isDirty()

So I think we could check it just once on set and it will be quite nice :)

[hkdobrev]

@ivank Have we actually changed the way Jam sets fields? If we did this should be closed.