Resolvable magic getters

[Sam Mousa]

Currently we have 2 kinds of magic getters:

1. Simple (implemented in yii\base\Component)
2. ActiveQuery (implemented in yii\db\BaseActiveRecord)

I propose replacing (2) with a generic implementation for resolvable getters. Resolvable getters would be defined as anything that describes an operation that you might want to change before executing.
When using it as a magic getter it would then get resolved with the default settings.
This is 100% analogous to how it currently works for ActiveQueryInterface.

public function __get($name) 
{
    ...
    if (array_key_exists($this->_resolved, $name)) {
        return $this->name;
    }

        $getter = 'get' . $name;
        if (method_exists($this, $getter)) {
            // read property, e.g. getName()
            $value = $this->$getter();
        } else {
            // behavior property
            $this->ensureBehaviors();
            foreach ($this->_behaviors as $behavior) {
                if ($behavior->canGetProperty($name)) {
                    $result = $behavior->$name;
                    break;
                }
            }
        }
        return $this->resolve($name, $result);
}

/**
* Allows child classes who override __get to reuse the resolving part.
*/
protected function resolve(string $name, $resolvable) 
{
    if ($resolvable instanceof Resolvable) {
        $this->_resolved[$name] = $resolvable = $resolvable->resolve($name, $this);
    }
    return $resolvable;
}

Note in the above example error handling is missing (unknown or write-only properties). But the idea is clear.
BaseActiveRecord should then be changed to use this generic approach.

[Alexander Makarov]

What's the problem you're trying to solve?

[Sam Mousa]

Clean up the AR implementation, also laying the groundwork for other kinds of resolvable properties, like virtual fields.
They can benefit from this, as would any cache-able property.

[Alexander Makarov]

That's pretty low-level and general concept that should be properly described in the guide. Hard to get it from reading phpdoc of PR. I see it as refactoring + more extension points. Correct?

[Sam Mousa]

That's correct

[Alexander Makarov]

Magic setters were removed altogether. Closing.