Cause error: Error: Cannot access trait constant self::CONTROL_FLASH_MESSAGE directly

[zeleznypa]

Last change on this line cause an error.

di/src/DI/DependencyChecker.php

Line 182 in f9ca71d

? is_object($tmp = $param->getDefaultValue()) ? ['object' => $tmp::class] : ['value' => $tmp]

Previous code works well

? is_object($tmp = Reflection::getParameterDefaultValue($param)) ? ['object' => $tmp::class] : ['value' => $tmp]

---

When I have a Presenter that use trait that contains the following code:

<?php

declare(strict_types=1);

namespace Interitty\FlashMessageControl;

use Nette\ComponentModel\IComponent as ComponentInterface;

use function assert;

trait FlashMessageControlHelperTrait
{
    /** All available control name constants */
    public const CONTROL_FLASH_MESSAGE = 'flashMessage';

    /**
     * Componentby name getter
     *
     * @param bool $throw Throw exception if component doesn't exist?
     * @return ComponentInterface|null
     */
    abstract public function getComponent(string $name, bool $throw = true): ?ComponentInterface;

    /**
     * FlashMessage control getter
     *
     * @param string $name [OPTIONAL]
     * @return FlashMessageControl
     */
    public function getComponentFlashMessage(string $name = self::CONTROL_FLASH_MESSAGE): FlashMessageControl
    {
        $control = $this->getComponent($name);
        assert($control instanceof FlashMessageControl);
        return $control;
    }
}

[dg]

Could you please report this as a PHP bug as well? That ReflectionParameter::getDefaultValue() crashes in this situation?

[zeleznypa]

The old version with ReflectionParameter::getDefaultValue() works well in the same situation

[dg]

So where's the problem?

[zeleznypa]

The problem is in the new version, where the code $param->getDefaultValue()) is used and cause the "Error: Cannot access trait constant self::CONTROL_FLASH_MESSAGE directly"

[dg]

So ReflectionParameter::getDefaultValue() isn't working so well, is it?

[zeleznypa]

ReflectionParameter::getDefaultValue() works well
$param->getDefaultValue() cause the "Error: Cannot access trait constant self::CONTROL_FLASH_MESSAGE directly"

Nette\DI 3.2.0 works well
Nette\DI 3.2.2 cause the "Error: Cannot access trait constant self::CONTROL_FLASH_MESSAGE directly"

[zeleznypa]

It is really strange, because when I tried to isolate the root cause in the 3v4l.org, it works also with the $param->getDefaultValue().

[dg]

What is the difference between ReflectionParameter::getDefaultValue() and $param->getDefaultValue() ????

[zeleznypa]

Sorry my fault :(

I was reporting and speaking about \Nette\Utils\Reflection::getParameterDefaultValue($param)

But you are speaking about \ReflectionParameter::getDefaultValue()

[mabar]

It is really strange, because when I tried to isolate the root cause in the 3v4l.org, it works also with the $param->getDefaultValue().

It happens only when $method is got from the trait reflection instead of the class reflection https://3v4l.org/s8ofg#v8.3.7
PHP (mostly) requires traits analysed in context of the class where the trait is used. And it makes sense in this case - constant could be defined by the class using the trait, not by the trait itself - https://3v4l.org/V4RNt#v8.3.7

(Interesting side-note: PHP allows to redefine constant value if it is defined by interface and overriden by a class or a trait, but constant value defined by a trait can't be redefined by a class, PHP would throw fatal error for that - https://3v4l.org/oYmEW#v8.3.7)

[zeleznypa]

Great point @mabar. When I debug/try/catch/parse and then debug the situation that happening in my code, the $method when it crashed return the Trait as a result for ->getDeclaringClass().

The previous mechanism was safe, because it was parsing the constant value different way than current version, that try to access the trait constant directly.

So the \Nette\Utils\Reflection::getParameterDefaultValue() still have some place and should not be deprecated, because it can parse default value also for methods from trait?

[dg]

And that brings us back to whether you could report this as a bug on PHP, because it should work.

[zeleznypa]

@dg Im not sure with that.

A) I have never report a bug to PHP. Where should I do that?

B) I think, that it is not a bug of PHP.

You cant call PHP Trait::CONST, so you cant ask for Reflection on trait and getDefaultParameter, that (from my point of view) do the same.

When you call the reflection on the class that use the trait, it works.

What do you think?