Undefined method in traits

[Vrtak-CZ]

Example code:

trait MyTrait
{
  public function foo()
  {
    return $this->bar();
  }
}

Call to an undefined method MyTrait::bar().

[ondrejmirtes]

This actually points out problem in your code 😊 If you use the trait in a
class without the bar method, the trait code will crash.

Correct solution is to define the bar method in the trait as abstract so
the trait can be used only in classes that define the bar method.

I want to write an article about this - we have several traits used by
presenters and controls, so I had to define methods like flashMessage and
redirect as abstract in the traits so they can be used only by the right
classes.

On Friday, 22 July 2016, Patrik Votoček notifications@github.com wrote:

Example code:

trait MyTrait{ public function foo() { return $this->bar(); }}

Call to an undefined method MyTrait::bar().

—
You are receiving this because you are subscribed to this thread.
Reply to this email directly, view it on GitHub
#9, or mute the thread
https://github.com/notifications/unsubscribe-auth/AAGZuEcPh1Hy8qWkWNrKWyR09r_wRbdmks5qYBn3gaJpZM4JSXFl
.

Ondřej Mirtes

[Vrtak-CZ]

Thank you. I know it's a bad idea to ignore not implemented methods in traits. It's first time when I use traits in my project.

Abstract function is a good idea. I'll try it.

[JanTvrdik]

@ondrejmirtes imho using abstract methods in traits is more hack than a solution because it does not actually enforce existence of the method with the same signature. You would need sth like https://docs.hhvm.com/hack/other-features/trait-and-interface-requirements

[ondrejmirtes]

@JanTvrdik I didn't know the signature isn't enforced (https://3v4l.org/YHMU0) but I still think the approach with abstract methods in traits is better than nothing at all...