Question

I am using Reflection against the following class:

class Constant {
    const CONSTANT = 3;
    public $test1 = 'CONSTANT';
    public $test2 = CONSTANT;
}

When using ReflectionClass::getDefaultProperties(); I get the following notice:

PHP Notice: Use of undefined constant CONSTANT - assumed 'CONSTANT'

on this line of code:

$defaultValues = $reflectionClass->getDefaultProperties();

First, I wonder why I get the notice here (I mean, I can’t anticipate/avoid the notice even though the code is 100% correct)?

And second, when using var_export($defaultValues[3]), it outputs 'CONSTANT' which is normal because it has been casted to string.

So, how can I output CONSTANT instead of 'CONSTANT' for $test2 and still output a quote-delimited string for $test1?

Edit: I get CONSTANT for both cases ($test1 and $test2) but because of that I can’t differentiate between them. I want to be able to know: that is a string, or that is the name of a constant.

Answer 1

why I get the notice here?

because you mean self::CONSTANT but tried to use global CONSTANT, e.g. your code assumes

const CONSTANT = 3;              // global constant

class Constant {
    const CONSTANT = 3;          // class constant
    public $test1 = 'CONSTANT';
    public $test2 = CONSTANT;    // refers to global constant
}

but you wanted to do this:

class Constant {
    const CONSTANT = 3;
    public $test1 = 'CONSTANT';
    public $test2 = self::CONSTANT; // self indicated class scope
}

With the latter, this

$reflectionClass = new ReflectionClass('Constant');
var_dump( $reflectionClass->getDefaultProperties() );

will give

array(2) {
  ["test1"]=>
  string(8) "CONSTANT"
  ["test2"]=>
  int(3)
}

Is there a way to get ["test2"] => self::CONSTANT via Reflection? No. The Reflection API will evaluate the constant. If you want self::CONSTANT you’d have to try some of the 3rd party static reflection APIs.

And obviously, if you want 'CONSTANT', write "'CONSTANT'".

Regarding EDIT:

I get CONSTANT for both cases ($test1 and $test2) but because of that I can’t differentiate between them. I want to be able to know: that is a string, or that is the name of a constant.

$foo = CONSTANT means assign the constant value to the foo property. It does not mean assign the constant itself. By assigning the value to a property, it no longer is a constant value. It’s mutable. The “name of a constant” is represented as a string. You can use ReflectionClass::hasConstant to check whether that string happens to also be the name of a defined constant in the class or use defined for global constants.